Mild photochemical tethering of [RuCl2(η6-arene)P?] complexes with P -stereogenic 2-biphenylylphosphines

Article

pubs.acs.org/Organometallics

6

Mild Photochemical Tethering of [RuCl (η ‑arene)P*] Complexes with

2

P‑Stereogenic 2‑Biphenylylphosphines

Miquel Navarro, Diego Vidal, Pau Clavero, Arnald Grabulosa,* and Guillermo Muller

̀ ̀

Departament de Química Inorganica, Universitat de Barcelona, Martí i Franques, 1-11, E-08028, Barcelona, Spain

*

S Supporting Information

ABSTRACT: The synthesis of enantiopure P-stereogenic

diarylphosphines PArPhR (Ar = 9-phenanthryl (a), 1-naphthyl

(

−

b), and 2-biphenylyl (c)) with an aryl group at the β (3; R =

CH CH (2-naphthyl)) or γ position (2; R = −CH Si(Me )-

2

6

CH Ph)) is described. Treatment of 2a with [RuCl (η -p-

2

6

cymene)] (Dim1) has led to complex [RuCl (η -p-cymene)-

2

(

κP-2a)] (4a). Attempts to displace the p-cymene substituent

by the pendant aryl group of the phosphine have failed.

6

Reaction of the ligands with [RuCl (η -methyl benzoate)]

2

6

(

Dim2) has furnished complexes [RuCl (η -methyl benzoate)-

2

κP-P*)] 6 and 7 (6a−c, P* = 2a−c; 7a−b, P* = 3a−b). The methyl benzoate of 6a and 6b has been successfully replaced by

6

the phenyl ring of the arm of the phosphine, yielding complexes [RuCl (κP-η -phenyl)-P*] (5a and 5b). Unexpectedly, complex

2

6

c has led to tethered [RuCl (κP-η -phenyl)-P(2-biphenylyl)PhR] complex (9c), where the coordinated phenyl ring belongs to

2

the 2-biphenylyl group. Reaction of P(2-biphenylyl)PhR (R = OMe, Me, i-Pr, and Fc (ferrocenyl)) with Dim2 has given

6

complexes [RuCl (η -methyl benzoate)(κP-P(2-biphenylyl)PhR)] (10c−13c). The replacement of methyl benzoate by the

2

phenyl ring of the 2-biphenylyl of the phosphine can be performed at room temperature in the presence of light, giving tethered

6

complexes [RuCl (κP-η -phenyl)-P(2-biphenylyl)PhR] (14c−17c). Phosphines bearing a substituted 2-biphenylyl group

2

(

PArPhR; d (Ar = 2-p-terphenylyl; R = OMe, Me, i-Pr), e (Ar = 2-m-terphenylyl; R = OMe, i-Pr), f (Ar = 2-(1′-naphthyl)phenyl;

R = OMe, i-Pr), and g (Ar = 2-(2′-naphthyl)phenyl; R = OMe, i-Pr) have been prepared. Phosphines f are present as a mixture of

atropisomers. The corresponding Ru complexes have been prepared and subjected to tethering. Tethered complexes with

phosphines d are single species in solution, whereas the rest of the phosphines give diastereomeric mixtures with little

stereoselection. All complexes have been evaluated in Ru-catalyzed hydrogen transfer of acetophenone in i-PrOH as a solvent

6

obtaining full conversions and up to 47% ee using precursor [RuCl (κP-η -phenyl)-P*] (26f, P* = P(2-(1′-naphthyl)phenyl)-

2

(

OMe)Ph.

INTRODUCTION

coordinated ligand, where A is the σ-donor atom. Many

■

5

6

5b

7

8

n

systems based on N, C (carbene), O, S, As, but especially

Half-sandwich organometallic complexes having an η -coordi-

nated (usually, n = 5, 6) aromatic carbocycle to a Ru(II) atom

9

on P as donor atoms are currently known. The chelate eﬀect of

the tether makes the complexes more rigid and less labile

compared to nontethered counterparts, which can be advanta-

geous in terms of stability and beneﬁcial in the stereo-

discrimination processes of asymmetric catalysis. In addition,

the multidentate nature of the ligand raises the typically rather

low isomerization barriers of racemization of stereogenic Ru

atoms.

^f^o^r^m^a^v^e^r^y^l^a^r^g^e^f^a^mⁱ^l^y^o^f^r^u^t^h^eⁿⁱ^u^m^c^o^m^p^o^uⁿ^d^s^t^h^a^t^a^r^e1

intensively studied for their applications in catalysis,

2

3

biomedicine, and supramolecular chemistry. Nowadays,

their structure, often described as pseudotetrahedral “three-

legged piano-stool”, their preparation methods, and their

chemistry are all very well developed. An advantage of this

type of complexes is that each of the four ligands can be

modiﬁed in quite an independent way, opening up the synthesis

of a myriad of neutral and cationic complexes. When chiral

complexes are sought, such as those aimed to be employed in

asymmetric catalysis, stereogenic elements can be introduced in

the ligands but also in the Ru center, which becomes

stereogenic if all four ligands are diﬀerent.

Our previously reported work in the area involved the

6

preparation of [RuCl (η -p-cymene)(κP)] complexes with

2

10

optically pure P-stereogenic diaryl phosphines. We also

prepared analogous complexes with more basic P-stereogenic

trialkyl phosphines, and some of them were subjected to

tethering by substitution of the p-cymene fragment by an

incoming aryl group present in the phosphine, aﬀording

An interesting subset of Ru-arene compounds is that of

complexes containing the π-coordinated neutral arene group

stemming from one of the σ-coordinated ligands. These are

usually called tethered complexes and can also be viewed as

having a polydentate (most often tetradentate) κA-η -

6

9r,11

complexes of the type [RuCl (κP-η -phenyl)-P*].

All of

2

4

Received: January 8, 2015

Published: February 26, 2015

6

©

2015 American Chemical Society

973

DOI: 10.1021/acs.organomet.5b00018

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Scheme 1. Preparation of Phosphines 2 and 3

Scheme 2. Preparation of 4a and Unsuccessful Tethering To Obtain 5a

these Ru precursors were used in transfer hydrogenation (TH)

reactions with good activities and moderate enantioselectivities

in some cases.

To have the whole picture, we then reasoned that it would be

interesting the design of less basic P-stereogenic diaryl

phosphines to explore the possible formation of tethered Ru

complexes and the evaluation of their catalytic potential in TH.

With phosphines bearing a 2-biphenylyl substituent, a mild,

light-activated tethering process has been uncovered. The

results of these studies are presented in this work.

further. The phosphine-boranes were characterized by the usual

techniques. As expected, a single resonance can be found at the

31

15−20 ppm region in the P NMR spectra. The signal is broad

due to the coupling with the boron nuclei. In the aliphatic

1

region of H NMR spectra, phosphine-boranes 2′ feature two

singlets at around 0 ppm, corresponding to the two

diastereotopic methyl groups of the dimethylsilyl fragment.

Interestingly, in compound 2′c, the six protons appear as a

singlet. The four protons of the two methylene bridges in 2′ are

all potentially diﬀerent in the NMR, each one coupling to the

other geminal proton and to the P atom in the case of the

P(CH Si(CH ) CH ) protons. That gives rise to a pattern that

RESULTS AND DISCUSSION

2

3 2

2

■

can be analyzed as two triplets for the P(CH Si(CH ) CH )

2

3 2

2

Phosphines with a Pending Aryl Group. The desired

ligands, bearing an aryl group at the β or γ position with respect

to the P atom, were conveniently prepared from the previously

protons and two doublets with a pronounced roof eﬀect for

13

1

P(CH Si(CH ) CH ) protons. In C{ H} NMR, a doublet at

2

3 2

2

12

around 10 ppm with a coupling constant of approximately 25

Hz can be assigned to the P(CH Si(CH ) CH ), whereas three

reported optically pure methylphosphine-boranes 1a−c, by

deprotonation with s-BuLi and quenching of the formed

carbanionic species with the suitable electrophiles at low

2

3 2

2

more doublets at the aliphatic region with small coupling

constants (<4 Hz) account for the other three nonaromatic

carbon atoms. Phosphine-boranes 3′ feature a complex, second-

9

r,11,12b,13

temperature (Scheme 1).

Carbanions derived from 1 reacted well with both

chlorobenzyldimethylsilane and with 2-(bromomethyl)-

naphthalene to furnish phosphine-boranes 2′ and 3′,

respectively, in good yields. It was found, however, that both

types of phosphine-boranes were invariably unpuriﬁed with a

certain amount of the starting methylphosphine-borane,

regardless of the excess of s-BuLi and/or electrophile employed.

Compounds 2′ are of an oily nature and had to be puriﬁed by

column chromatography, whereas 3′a and 3′b are solids and

could be obtained pure after recrystallization. In contrast,

compound 3′c is a pasty solid that could not be obtained pure

by neither column chromatography nor recrystallization despite

many attempts, and therefore, its synthesis was not pursued

1

order H spectra at 2.5−3 ppm for the four aliphatic protons of

the ethylene bridge. In the ¹³C{ H} NMR, a doublet with a

large P−C coupling constant of 35 Hz at 28 ppm and a small

doublet (3′a) or a singlet (3′b) can be assigned to the

1

PCH CH and PCH CH carbon atoms, respectively.

2 2 2 2

Deboronation of 2′ and 3′ in neat morpholine under

12b

standard conditions for this type of ligand was carried out

straightforwardly, yielding phosphines 2 and 3, respectively, as

air-sensitive oils or semisolids in good yields. The success of the

deboronation reaction was apparent in the ³¹P{ H} spectra,

which consists of singlets appearing below −25 ppm, with a

strong deshielding compared to the phosphine-boranes, as

1

9

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Scheme 3. Preparation of Complexes 6 and 5

expected. H and ¹³C{ H} NMR are also consistent with the

1

reduction from Ru(III) to Ru(II) would aromatize the diene to

5c,15

structure of the free ligands. In contrast to phosphine-boranes

a phenyl ring, as reported by several authors

on the

1

3

′, in the H NMR spectra, the four aliphatic protons of the

preparation of tethered complexes based on dinitrogenated

ligands. The synthesis of the ligand, however, would be

challenging as the chlorosilane precursor with the methyl-

cyclohexadiene group is not easily obtainable.

ethylene bridge of phosphines 3 appear separated in two

multiplets, accounting for two protons each.

Ru-η -Arene Complexes. Study of the Tethering

6

Process. Phosphine 2a was chosen to perform the initial

Another strategy would be changing the relatively electron-

rich p-cymene fragment by a more electron-poor arene to be

displaced by the incoming phenyl group from the ligand. This

method has indeed been used by several groups

when thermal displacement of the p-cymene fragment failed. In

complexation and tethering studies with Ru. Therefore,

1

0a

following previously published research,

mononuclear

5

a,9b,e,i,l,n,16

complex 4a was easily obtained by splitting the Ru-p-cymene

dimer Dim1 with 2a in dichloromethane at room temperature

(

Scheme 2).

these studies, alkyl benzoates are commonly used as a more

labile η -coordinated arene. Therefore, the methyl benzoate Ru

6

Complex 4a is an orange solid, which was characterized by

the usual techniques, conﬁrming the identity of the compound.

dimer, Dim2, was prepared from methyl 2,5-cyclohexadiene-

1

13

1

17

9i

For example, in the aliphatic region of the H and C{ H}

NMR, apart from the peaks corresponding to the phosphine

fragment, four peaks can be assigned to the isopropyl and

methyl groups of the p-cymene fragment and four CH

resonances can be found due to the coordinated arene ring.

Complex 4a was subjected to several sets of experimental

conditions with the objective of intramolecularly substituting

the p-cymene ring by the phenyl ring of the silylated arm of the

phosphine, to have access to tethered complex 5a, which is

analogous to previously reported complexes with trialkylphos-

carboxylate, according to literature procedures. From this

dimer, the three mononuclear complexes 6a−6c were prepared

(Scheme 3).

The preparation was analogous to the p-cymene counterparts

but with dimer Dim2. Indeed, this dimer had an advantage over

Dim1: its very low solubility in dichloromethane made the

puriﬁcation of complexes very easy by removing any excess of

dimer by a simple ﬁltration. For this reason, an excess of dimer

was usually employed, a method that furnished the desired

complexes as brown solids in moderate yields after puriﬁcation

by recrystallization. In contrast to Dim2, complexes 6 are very

soluble in common organic solvents such as dichloromethane

or THF but insoluble in pentane or hexane. The character-

ization data fully support the proposed structures of 6.

9

r

phines. The ﬁrst experiments were carried out by heating a

chlorobenzene solution of 4a at 130 °C for several hours under

a nitrogen atmosphere, as typically described in the

9

a,c,r,14

literature.

The solution turned dark green, and after

1

13

1

evaporation of the solvent, a muddy dark residue could be

isolated, whose ³¹P NMR and H NMR were extremely broad

and uninformative, probably due to the presence of Ru(0) and/

or Ru(III) species. Several attempts of varying the temperature

Accordingly, H and C{ H} NMR spectra show, apart from

the peaks corresponding to the phosphine moiety, 5 distinct H

1

13

1

(4−7 ppm region) and C C{ H} (80−100 ppm) resonances,

corresponding to the 5 CH groups of the coordinated methyl

benzoate ring. A singlet for the methyl group of the arene

(

rt−130 °C) and/or the reaction time (2−24 h) were equally

1

13

1

unsuccessful since either decomposition or starting complex 4a

was invariably found. The same lack of success was found upon

changing the solvent to 1,2-dichloroethane (bp 84 °C), THF

appeared at 4 and 53 ppm in the H and C{ H} spectra,

respectively. Additionally, a strong sharp band at 1728 cm⁻in

the IR spectra is very diagnostic of the CO stretching of the

carbonyl from the ester group.

1

(

bp 66 °C), or 1,4-dioxane (bp 101 °C). The results show that

probably complex 4a is simply not robust enough to withstand

the harsh conditions usually employed to force the tethering to

take place. This is likely due to the diarylic nature of phosphine

The tethering reaction of complex 6a was attempted using

dichloromethane/THF at 120 °C in an autoclave, following the

9b,e

conditions described in the literature.

(Scheme 3). Gratify-

2

a, in contrast to the trialkyl phosphines used in previous

ingly, complex 5a could be successfully obtained as an orange

powder after recrystallization. IR conﬁrmed the decoordination

of the methyl benzoate ring since no carbonylic CO

9r

reports, which bear stronger Ru−P bonds.

A few attempts to obtain 5a directly from ligand 2a and

RuCl ·xH O in ethanol, inspired by a recent paper by Yu, Liu,

and co-workers were carried out. Once again, decomposition

or no reaction was found depending on the conditions used.

At this point, it became clear that, to succeed in the synthesis

of 5a, another strategy had to be used. A literature search

suggested two possibilities. The ﬁrst one would be the synthesis

of a ligand similar to 2a but bearing a 1,3- or 1,4-cyclohexadiene

group instead of the tethering phenyl group. With such a

−1

stretching band at around 1730 cm could be observed. In

3

2

9

p

31

1

P{ H} NMR, a downﬁeld shift of ca. 8 ppm from 5a (δ = 23.8

ppm) compared to 6a (δ = 32.0 ppm) was observed, in

9

r,18

1

accordance with the formation of a chelate.

The H NMR

spectrum of 5a shows the presence of 5 protons in the

6

coordinated η -arene region, displaced upﬁeld compared to 6a.

Starting from 6b, complex 5b could be easily obtained using the

same method and shows very similar spectroscopic features. In

contrast, complex 6c did not lead to the corresponding 5c

ligand, complex 5a should be accessible from RuCl since the

3

9

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complex but a diﬀerent product that will be discussed later. For

complex 5a, crystals of suﬃcient quality to perform X-ray

diﬀraction studies could be grown from dichloromethane/

hexane. A representation of the crystal structure of 5a is shown

in Scheme 4.

These data shows that the strain created by the “claw eﬀect” of

9

b,r,11

the arene-phosphorus ligand

is rather limited with a bridge

of three atoms, as observed in previously reported com-

9a,c−e,i,l,n,r,19

pounds.

After the successful preparation of 5a and 5b, complexes 7a

and 7b were prepared from Dim2 and phosphines 3a and 3b,

respectively, with the aim of obtaining the corresponding

tethered complexes 8 (Scheme 5). These complexes are

interesting because, in principle, they could be present as a

mixture of two diastereomers depending on the face of the 2-

naphthyl group coordinated to the Ru atom, but interestingly,

with certain trialkylphosphines related to the phosphines

Scheme 4. ORTEP Representation (Thermal Ellipsoids

Drawn at 50% Probability Level, H Atoms Removed for

Clarity) of One of the Crystallographically Independent

a

Molecules of 5a

11

discussed here, only one isomer was found.

Complexes 7 exhibited the expected characterization data.

1

The only remarkable feature is that, in H NMR, all four H

atoms of the ethylene bridge of the phosphine appeared

separated as broad multiplets, in contrast to the phosphine-

boranes 3′ and free ligands 3, in which they were severely

overlapped.

Complexes 7 were subjected to the same conditions as those

of 6 (Scheme 3), but unfortunately, not even a trace of

complexes 8 could be spotted in the NMR spectra of the

isolated crude solids. Decomposition products and/or starting

complexes 7 were invariably observed under diﬀerent

conditions. This shows that, in the tethering process, the

6

important factor is not only the leaving ability of the η -

coordinated arene but the incoming arene also plays an

important role.

a

Distances (Å) and angles (deg): Ru(1A)−Cl(1A), 2.394(4);

Ru(1A)−Cl(2A), 2.429(3); Ru(1A)−P(1A), 2.357(3); P(1A)−C-

The reaction of complex 6c under the reaction conditions

employed to obtain complexes 5a and 5b led to a dark brown

solid, which did not result from the tethering of 6c by the

silylated arm of the phosphine, forming compound 5c as

expected, but from the tethering by the phenyl ring of the 2-

biphenylyl substituent of the phosphine, yielding complex 9c

(Scheme 6).

(

1

10A), 1.807(13); P(1A)−C(11A), 1.830(11); P(1A)−C(17A),

.839(13); C(6A)−C(7A), 1.552(19); C(7A)−Si(1A), 1.885(13);

C(10A)−Si(1A), 1.932(12); Ru(1A)−C , 2.209; Ru(1A)−

center , 1.720; P(1A)−Ru(1A)−Cl(1A), 90.52(13); P(1A)−Ru-

arene,mean

arene

(

1A)−Cl(2A), 86.66(12); Cl(1A)−Ru(1A)−Cl(2A), 87.35(13); P-

1A)−C(10A)−Si(1A), 117.9(6); C(10A)−Si(1A)−C(7A), 111.9(6);

C(6A)−C(7A)−Si(1A), 119.9(9); C(6A)−C(7A)−Si(1A)−C(10A),

4

7.17; P(1A)−C(10A)−Si(1A)−C(7A), 3.14.

1

IR and H NMR spectra of the brown powder indicated that

decoordination of the methyl benzoate had taken place and that

another phenyl ring of the phosphine had coordinated to the

Ru center, as 5 resonances were present in the coordinated

Complex 5a adopts the ordinary “three-legged piano-stool”

6

pseudotetrahedral geometry of the [Ru(η -arene)L ] com-

3

1

plexes, with the Ru atom in a distorted octahedral environment.

arene region (5−7 ppm) of the H NMR spectrum. Although

The structure conﬁrms the expected S absolute conﬁguration

these spectral features agree with the formation of complex 5c,

the chemical shifts and shapes of the 5 protons of the

coordinated aryl were very diﬀerent from those of 5a and 5b

(Scheme 7).

6

(

as free ligand) of 2a. The Ru atom is η -coordinated to the

phenyl ring of the tethering arm of the phosphine, which acts as

1

6

tetradentate κ -η ligand. The distances of chlorine atoms to the

mean plane deﬁned by the carbon atoms of the coordinated

arene are very similar (3.167 and 3.164 Å for Cl(1) and Cl(2),

respectively), and the P(1) lies 3.104 Å below that plane,

whereas the benzylic carbon atom C(7A) is almost coplanar to

that plane, being placed only 0.056 Å below it. The angle

between this plane and the C(6A)−C(7A) bond is only 2°.

31

1

P{ H} chemical shifts of 5a and 5b (+32 and +30.8 ppm,

respectively) were strongly shifted upﬁeld compared to that

observed in 9c (+50.7 ppm), pointing to that the compound

had a very diﬀerent structure, possibly containing a more

18

1

13

1

strained ruthenacycle than in 5. In addition, H and C{ H}

NMR showed the presence of peaks in the aliphatic region

Scheme 5. Preparation of Complexes 7 and Their Unsuccessful Tethering Reaction

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Scheme 6. Tethering of 6c To Furnish 9c and not 5c

1

6

Scheme 7. H NMR Spectra (η -Coordinated Arene Region)

Scheme 8. ORTEP Representation (Thermal Ellipsoids

of Complexes 5a (Top), 5b (Middle), and 9c (Bottom)

Drawn at 50% Probability Level, H Atoms Removed for

Clarity) of 9c

a

Distances (Å) and angles (deg): Ru(1)−Cl(1), 2.3922(17); Ru(1)−

assignable to the uncoordinated silylated arm of the phosphine

and the integration ﬁtted with the presence of the entire

phosphine ligand ruling out any decomposition of the ligand.

All of these data, along with the results of microanalysis, were

consistent with the proposed structure of 9c. The deﬁnitive

proof that the tethering had occurred by coordination of the

phenyl ring of the 2-biphenylyl substituent of the phosphine

instead of the phenyl ring of the silylated arm came from the

crystal structure of 9c, determined by X-ray diﬀraction (Scheme

Cl(2), 2.3935(16); Ru(1)−P(1), 2.3136(18); P(1)−C(12), 1.826(6);

P(1)−C(13), 1.801(7); P(1)−C(19), 1.811(6); C(6)−C(7),

1.529(7); C(7)−C(12), 1.385(10); C(19)−Si(1), 1.895(6); Ru(1)−

C

, 2.182; Ru(1)−center , 1.679; P(1)−Ru(1)−Cl(1),

arene,mean

arene

89.23(6); P(1)−Ru(1)−Cl(2), 91.03(6); Cl(1)−Ru(1)−Cl(2),

8

1

7.36(7); P(1)−C(12)−C(7), 115.9(5); C(6)−C(7)−C(12),

18.9(5); P(1)−C(12)−C(7)−C(6), 6.3(9).

2

0a,21b,23

Binap

Ru complexes under acidic conditions. Faller

9h,j,m

8

).

and co-workers

described the coordination of 2-bipheny-

6

The structure contains the Ru atom in a pseudotetrahedral

lyldicyclohexylphosphine and related ligands in a κP-η -phenyl

fashion to the [RuCl ] fragment by treatment of [RuCl (η -

benzene) ] with the ligand in DMF at 100 °C, explored the

resolution of the chiral complexes obtained, and used some of

the complexes in asymmetric Diels−Alder reactions. Similarly,

Mikami and co-workers prepared, also by thermally induced

substitution of an η -benzene ring, a few chiral tethered Ru

6

geometry with the coordinated two chlorine atoms, the

2

6

phosphorus atom, and the η -coordinated terminal phenyl

2 2

ring of the 2-biphenylyl substituent of the phosphine, which has

the S absolute conﬁguration as a free ligand, as expected. The

two phenyl rings of the 2-biphenylyl substituent are forced to

be approximately perpendicular to allow the coordination of the

terminal one. In contrast to 5a, the distances from the mean

plane deﬁned by the coordinated arene C atoms to the Cl

atoms (3.212 and 3.153 Å for Cl(1) and Cl(2), respectively)

are much longer than the distance from the plane to the P atom

20e

6

complexes bearing a 2′-substituted 2-biphenylyl phosphine

2

0f

using a chiral diamine. Wehmschulte and co-workers

described achiral tethered Ru complexes with m-terphenylyl-

phosphines, prepared again by thermally induced substitution

of an η -p-cymene fragment. Finally, a recent paper of

Ackermann and co-workers on Ru-catalyzed hydroarylation

of methylenecyclopropanes described the preparation of

6

(

2.820 Å), whereas C(7) lies 0.267 Å below that plane. The

9q

angle between this plane and the C(6)−C(7) bond is 10°. This

shows a signiﬁcant “claw eﬀect” exerted by the li-

gand.

9

b,e,g,h,j,m,o−r,11,16a,b,20

6

24

[RuCl (κP-η -X-Phos)] by heating a mixture of the X-Phos

2

The coordination of the phenyl group of the 2-biphenylyl

substituent of a phosphine in Ru complexes is rare, but not

unprecedented in the literature. It was ﬁrst reported by

ligand and [RuCl (COD)] at 120 °C for 24 h. To the best of

2 n

our knowledge, however, the present paper is the ﬁrst to

describe this kind of tethering with a P-stereogenic ligand.

During the characterization of 6c, it was found that multiple

20a,21

Pregosin and co-workers

chiral diphosphine MeO-Biphep cooordinated in a κP-η -

with Ru complexes bearing the

6

13

31

peaks appeared in the C NMR spectrum and the P NMR

spectrum showed that 9c was spontaneously being formed.

Indeed, it was found that, when an NMR tube containing 6c

phenyl mode and later by the same group with complexes

2

0a,22

derived from decomposition of MeO-Biphep

and

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Scheme 9. Preparation of Nontethered (6c, 10c−13c) and Tethered (9c, 14c−17c) Complexes

−4

Figure 1. (Left) UV−vis spectral changes observed on irradiation of a 2.5 × 10 M dichloromethane solution of compound 13c at 365 nm (blue,

initial; red, 20 min; black, 60 min). (Right) Time-resolved ³¹P{ H} NMR spectral changes observed on irradiation of a 1.0 × 10

1

−2

M

dichloromethane solution of compound 11c at 365 nm.

dissolved in CDCl was left unattended in the laboratory for

complexes exposed to a conventional desk lamp for 4 h. During

3

several days, it evolved to give 9c quantitatively. Interestingly,

the reaction did not take place in the absence of light.

Therefore, much milder experimental conditions to obtain 9c,

consisting of stirring a solution of 6c in dichloromethane for 4

h with irradiation with a conventional desk lamp, were

successfully applied. This contrasts with the rather harsh

conditions described in the literature for the preparation of

related compounds, as described in the preceding paragraph.

Ru Complexes with Phosphines Bearing an Unsub-

stituted 2-Biphenylyl Fragment. It seems clear that the 2-

biphenylyl substituent of the phosphine is very prone to

tethering. Therefore, we carried out a study with a series of

phosphines bearing unsubstituted and substituted 2-biphenylyl

groups. The ﬁrst series of complexes studied were those with

phosphines containing an unsubstituted 2-biphenylyl group.

Hence, previously reported enantiopure phosphines P(2-

this period, the initial orange solutions of 10c−13c gradually

turned darker, indicating the formation of the tethered

complexes, which were isolated as dark brown solids after a

single recrystallization to remove the methyl benzoate formed.

The identity of the new complexes 14c−17c was supported by

the data from the usual characterization techniques. IR

spectroscopy showed the disappearance of the carbonyl band,

proving the decoordination of the methyl benzoate fragment. A

strong downﬁeld shift (20−30 ppm) of the P{ H} resonances

is observed going from complexes 10c−13c to their tethered

counterparts 14c−17c. The rest of the data agree with the

proposed structures.

31

1

To gain further insight in the tethering reaction, the light-

driven process was examined in more detail for complexes 11c

and 13c (Figure 1).

Figure 1 shows the evolution of the UV−vis spectrum of a

solution of 13c recorded irradiating at the maximum observed

for this complex (365 nm) during 1 h as well as the evolution of

1

2b,25

12b

biphenylyl)PhR (R = OMe,

Me,

i-Pr , and

2

5b

ferrocenyl ) were reacted with Dim2, aﬀording the expected

complexes 10c−13c, and their tethering reaction was studied

31

1

the P{ H} spectrum of 11c also under irradiation. From these

data, it is clear that the changes observed in the spectra

correspond to the neat tethering of the phosphine ligand in 11c

and 13c onto the Ru center to produce the corresponding

tethered complexes 15c and 17c respectively. A screening of

the excitation energy needed for the tethering processes was

performed by conducting the experiment of Figure 1 (left) at

diﬀerent wavelengths for complex 11c. The use of narrowband

ﬁlters up to 580 nm produced, in all cases, the appearance of

the tethered complex 15c with the same time scale (Figure 2);

only the use of a ﬁlter for λ > 850 nm proved to be eﬀective for

the suppression of the photochemically activated tethering

processes.

(

Scheme 9).

The characterization data of 10c−13c clearly conﬁrmed their

structure. As expected, a strong absorption around 1727−1731

−1

cm assignable to the carbonyl group appears in the IR

1

spectra. In H NMR spectra, apart from the peaks of the

phosphine part, a singlet accounting for the COOMe group and

6

5

CH resonances in the coordinated η -arene region can be

seen for all compounds. For complex 13c, the peaks of the

ferrocenyl group appear as a broad signal at 3.70 ppm

integrating 5 H, accounting for the unsubstituted Cp ring,

and four singlets scattered between 4 and 6.5 ppm,

corresponding to the substituted Cp ring.

The tethering reaction for all complexes was found to be

complete after stirring a dichloromethane solution of the

Finally, complex 10c′, with the same phosphinite ligand as

6

10c but having an η -coordinated p-cymene instead of methyl

9

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Scheme 11. Preparation of Aryl Bromides ArBr(d−g)

Figure 2. Time-resolved absorbance changes at 366 nm observed on

irradiation at 2.5 × 10⁻⁴M dichloromethane solution of compound

1

1c at diﬀerent wavelengths.

benzoate, was prepared to study the eﬀect of the leaving η⁶-

arene in the tethering reaction. The complex was subjected to

the same reaction conditions used to tether 10c. It was found

that the tethering reaction to produce 14c took place but rather

slowly because, after 24 h of irradiation, the reaction mixture

still contained around 10% of unreacted 10c′. As expected,

methyl benzoate complexes suﬀer the tether reaction much

faster than p-cymene counterparts because the former fragment

is a much better leaving group.

Phosphines with a Substituted 2-Biphenylyl Frag-

ment. It seems clear that, with the Ru systems presented here,

the tethering reaction is general when the phosphine contains

an unsubstituted 2-biphenylyl group. It was deemed interesting

to study whether the same happens with phosphines bearing a

substituted 2-biphenylyl group. To this end, four families of

ligands of such a class were selected (Scheme 10).

type PArPhR (Ar = 2-p-terphenylyl (d), 2-m-terphenylyl (e), 2-

(

1′-naphthyl)phenyl (f), and 2-(2′-naphthyl)phenyl (g); R =

OMe, Me, i-Pr) (Scheme 12).

Most of the reactions worked smoothly under the conditions

10b

described to prepare phosphines d,

but in some steps

experimentation was needed in order to optimize the yields and

minimize undesired side reactions for some of the compounds.

Thus, lithiation of ArBre by n-BuLi was found troublesome,

giving incomplete conversions despite changing the temper-

ature (−78 to −20 °C) and solvent (Et O, THF), and for this

2

reason, aminophosphine-borane 19e was found to be invariably

25b

unpuriﬁed by the butyl-containing aminophosphine-borane,

Scheme 10. Substituted 2-Biphenylyl-Containing Phosphines

which was very diﬃcult to remove. For this reason, a slight

excess of ArBre had to be used to be able to obtain 19e as a

single compound after column chromatography puriﬁcation.

The same impurity was found in the synthesis of the

aminophosphine-boranes 19f and 19g, but in this case,

increasing the temperature of the lithiation from −78 to −25

°

C was enough to avoid the formation of the unwanted butyl-

containing aminophosphine-borane. The methanolysis step

worked well for 19e, but in the case of 19f and 19g, an excess of

sulfuric acid and an extended reaction time were needed to

achieve full conversion of the starting aminophosphine-boranes.

Finally, an excess of the isopropyllithium and strict control of

temperature and time were required in order to obtain

phosphine-boranes 23e−g as pure compounds. The ﬁnal

phosphine-boranes as well as the intermediates were fully

characterized by the usual techniques, conﬁrming their

structure.

Phosphines containing the 2-p-terphenylyl group (d; R =

OMe, Me, i-Pr) were recently described by us, whereas the

rest of the ligands are reported here for the ﬁrst time. The

10b

ligands were prepared using the Juge−

́

Stephan method-

in which the bulky aryl group is introduced at the

1

0b,26

ology,

P atom via an organolithium reagent, which is, in turn, prepared

by metalation with n-BuLi of the corresponding aryl bromide

precursor. These precursors were prepared by Suzuki−Miyaura

couplings (Scheme 11).

The family of compounds containing the 2-(1′-naphthyl)-

phenyl fragment (19f, 20f, 21f, 23f, and 25f) deserve further

comment because all of them are present as mixtures of two

isomers in solution according to NMR. The two isomers are

probably diastereomers arising from restricted rotation of the

naphthyl-phenyl fragment. Interestingly, the proportion of the

isomers changed depending on the intermediate; it ranged from

1:1 for phosphinites 20f and 21f to 1:3 for aminophosphine-

borane 19f. This kind of diastereomeric mixtures have a recent

All aryl bromides were prepared by coupling 2-bromoiodo-

benzene with the appropriate (and commercially available)

10b,27

arylboronic acid, following modiﬁed literature methods.

The synthesis and characterization of ArBre is included in the

experimental part since details have not been reported

2

7b

previously.

The Juge−

́

Stephan method is based on chemo- and

28

stereoselective substitution reactions starting from oxazaphos-

pholidine-borane 18, easily prepared from commercially

available (−)-ephedrine, followed by a deprotection step in

literature precedent when Mohar and Stephan studied a few

related o-biarylphosphine-boranes. To gain further insight into

this issue, the crystal structure of phosphine-borane 23f was

obtained by X-ray diﬀraction methods (Scheme 13).

2

6

neat amine. In this work, we prepared nine phosphines of the

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Scheme 12. Juge−

Article

́

Stephan Method To Prepare the Substituted Biphenylyl-Containing Phosphines

Scheme 13. ORTEP Representation (Thermal Ellipsoids

Drawn at 50% Probability Level, H Atoms Removed for

Clarity) of One of the Crystallographically Independent

phenyl substituent of the phosphine. The three crystallo-

graphically diﬀerent molecules in the unit cell have the same

orientation of the 2-(1′-naphthyl)phenyl fragment, and hence,

a

Molecules of 23f

only one stereoisomer is present in the crystal, as conﬁrmed by

1

H NMR in CDCl . The observed isomer corresponds to the

3

major one found in the solution of bulk 23f, in which the

isomeric ratio is 1:1.6. To study the epimerization process, a

monocrystal of 23f was dissolved in C D and left standing for

6

2

4 h with no changes being observed. The NMR tube was then

heated to 60 °C, and the progress of the reaction was

1

monitored by recording H NMR spectra at intervals of 2 h

(

see the Supporting Information). It was found that, initially,

only one compound was present, but after 2 h, a 1:2.3 ratio of

diastereomers was found, whose ratio slightly changed to reach

a constant value of 1:2 after 10 h. The results show that the

epimerization process does not happen at room temperature,

but is relatively fast at 60 °C. The obtained thermodynamic 1:2

isomeric ratio is slightly higher than the 1:1.6 ratio from bulk

2

3f resulting from synthesis. Semiempirical calculations (PM3

a

level; see the Supporting Information) on the energy proﬁle of

this compound as a function of the phenyl-naphthyl torsion

angle revealed two very similar energy minima with a

interconversion barrier higher than 100 kJ/mol, which is not

accessible at room temperature, in accordance with the

experimental results.

Distances (Å) and angles (deg): P(1A)−B(1A), 1.899(8); P(1A)−

C(1A), 1.824(6); P(1A)−C(17A), 1.808(7); P(1A)−C(23A),

1

.838(6); C(6A)−C(7A), 1.4863(10); B(1A)−P(1A)−C(1A),

12.1(3); B(1A)−P(1A)−C(17A), 110.1(3); B(1A)−P(1A)−C-

(

23A), 111.6(3); C(1A)−C(6A)−C(7A)−C(16A), 71.04.

Ru Complexes with Phosphines Bearing a Substituted

-Biphenylyl Fragment. With the ligands in hand, we started

The unit cell of 23f contains three crystallographically

2

diﬀerent molecules with very similar geometric parameters, and

consequently, only one of them is shown in the ﬁgure. The

crystal structure conﬁrms that the absolute conﬁguration of the

P atom is S as expected. The distances and angles are in the

by studying the coordination to Ru and subsequent tethering of

the obtained complexes of phosphines d, containing the 2-p-

terphenylyl fragment (Scheme 14).

Complexes 26d−28d could be obtained by the splitting

reaction of Dim2 with the suitable ligand in the form of stable

orange solids. The characterization data proved their identity

and purity. Suitable crystals for X-ray diﬀraction could be

10b,12,29

usual range for similar compounds.

The phenyl and

naphthyl rings of the 2-(1′-naphthyl)phenyl group of the

phosphine are deviated 19° from perpendicularity. There is a π-

stacking interaction between the naphthyl group and the other

Scheme 14. Preparation of Ru Complexes with Phosphines Containing a 2-p-Terphenylyl Fragment

9

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Scheme 15. ORTEP Representations (Thermal Ellipsoids Drawn at 50% Probability Level, H Atoms Removed for Clarity) of

a

2

6d (left) and 27d (right)

a

Distances (Å) and angles (deg) for 26d: Ru(1)−Cl(1), 2.3958(6); Ru(1)−Cl(2), 2.3856(6); Ru(1)−P(1), 2.3226(6); P(1)−C(9), 1.798(2);

, 2.193; Ru(1)−center

P(1)−C(15), 1.833(2); P(1)−O(3), 1.6094(17); C(16)−C(21), 1.494(3); C(24)−C(25), 1.478(4); Ru(1)−C

1

Cl(2), 2.4007(15); Ru(1)−P(1), 2.3658(18); P(1)−C(9), 1.811(6); P(1)−C(10), 1.818(6); P(1)−C(16), 1.843(6); C(21)−C(22), 1.499(8);

C(25)−C(28), 1.483(8); Ru(1)−C

Ru(1)−Cl(2), 90.09(5).

,

arene

arene,mean

.701; P(1)−Ru(1)−Cl(1), 86.98(2); P(1)−Ru(1)−Cl(2), 90.91(2); Cl(1)−Ru(1)−Cl(2), 90.74(3). For 27d: Ru(1)−Cl(1), 2.4037(16); Ru(1)−

, 2.199; Ru(1)−center , 1.688; P(1)−Ru(1)−Cl(1), 85.90(6); P(1)−Ru(1)−Cl(2), 82.35(5); Cl(1)−

arene,mean

arene

obtained for 26d and 27d. The molecular structures of these

two compounds are represented in Scheme 15.

diagnostic peaks were four doublets appearing at the 4.8−6.5

6

ppm region, assignable to the expected four η -coordinated CH

In contrast to the relatively large number of reported

groups of the tethering central phenyl ring of the 2-p-

terphenylyl fragment of the phosphine.

The structure of 31d could be obtained by single-crystal X-

ray diﬀraction methods. The molecular structure of this

complex is represented in Scheme 16.

6

structures of complexes of the type [RuCl (η -p-cymene)P] (P

2

9

b,p,r,10,30

=

monophosphorus ligand),

to the best of our

knowledge, there is none of any analogous complex with

methyl benzoate as a coordinated arene. The structure of

6

9b

[

RuCl (η -ethyl benzoate)] is known and also of its complex

2

6

2

RuCl(η -ethyl benzoate)(κ -triphos)]PF , with a dicoordi-

nated triphosphine ligand. The most similar structure to 26d

and 27d was reported in an early paper of Salvadori and co-

6

Scheme 16. ORTEP Representation (Thermal Ellipsoids

Drawn at 50% Probability Level, H Atoms Removed for

31

a

Clarity) of 31d

3

2

6

workers, who described the structure of [RuCl (η -arene)P]

2

(

arene = methyl-o-toluate, P = (+)-neomenthyldiphenyl-

phosphine). Complexes 26d and 27d adopt the ordinary

three-legged piano-stool” pseudotetrahedral geometry of the

“

[

6

Ru(η -arene)L ] complexes, with the Ru atom in a distorted

3

octahedral environment. The structures conﬁrm the expected R

and S absolute conﬁgurations (as free ligands) of 21d and 24d,

respectively. An interesting feature of the structures of

complexes 26d and 27d is that the carboxylate fragment is

located directly over the two Cl atoms and exactly opposite to

the position of the phosphine, probably for steric reasons. For

26d, the two Cl atoms and the P atoms are approximately at

the same distance (3.083, 3.053, and 3.099 Å) from the mean

plane deﬁned by the coordinated C atoms of the arene ring. In

contrast, in 27d, the distances Cl−arene (3.126 and 3.029 Å for

Cl(1) and Cl(2), respectively) are much shorter than the

P(1)−arene (3.306 Å). The structure of 27d can be

conveniently compared to the parent compound with the

a

Distances (Å) and angles (deg): Ru(1)−Cl(1), 2.4007(7); Ru(1)−

Cl(2), 2.4067(8); Ru(1)−P(1), 2.3497(7); P(1)−C(18), 1.839(3);

P(1)−C(19), 1.834(3); P(1)−C(25), 1.853(3); C(6)−C(7),

1.489(4); C(10)−C(13), 1.498(4); C(13)−C(18), 1.391(5);

10b

same ligand but with p-cymene as coordinated arene, 27d′.

Ru(1)−C

, 2.209; Ru(1)−center , 1.689; P(1)−Ru(1)−

arene,mean

arene

Interestingly, the structural parameters are very similar for both

Cl(1), 89.64(3); P(1)−Ru(1)−Cl(2), 95.63(3); Cl(1)−Ru(1)−

Cl(2), 86.61(3); P(1)−C(18)−C(13), 116.6(2); C(10)−C(13)−

C(18), 117.9(3); P(1)−C(18)−C(13)−C(10), 1.3(4).

9

b

compounds, and therefore, it is not possible to aﬃrm that

methyl benzoate is a more labile arene compared to p-cymene

in Ru(II) complexes comparing only the crystal structures.

The tethering reaction of 26d−28d under the usual

conditions took place without any remarkable problem, yielding

the corresponding tethered complexes 29d−31d as reddish

solids after 4 h of reaction time. The disappearance of the C

O stretching band in the IR spectra and the large downﬁeld

6

The structure shows the η -coordination of the middle ring

of the 2-p-terphenylyl arm of the phosphine as expected. The

structure clearly reveals the “claw eﬀect” of the η -arene−P

ligand, in parallel to 9c.

Å below the plane deﬁned by the C atoms of the coordinated

arene ring in comparison to only 0.072 Å for C(6) while P(1) is

6

9b,r,11

Therefore, C(13) is located 0.237

3

1

shift (22−34 ppm) of the P{ H} NMR signal conﬁrmed the

1

success of the reactions. In the H and NMR spectra, the most

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Scheme 17. Preparation of Ru Complexes with Phosphines Containing a 2-m-Terphenylyl Fragment

Scheme 18. Preparation of Ru Complexes with Phosphines Containing a 2-(1′-Naphthyl)phenyl Fragment

Scheme 19. Preparation of Ru Complexes with Phosphines Containing a 2-(2′-Naphthyl)phenyl Fragment

pushed approximately 0.286 Å closer to that plane compared to

the Cl atoms. The angle between this plane and the C(10)−

C(13) bond is 9°. In the 2-p-terphenylyl group, the bridging

phenyl ring and the coordinated one are approximately

perpendicular, as found in 9c.

complexes 26e and 28e, this reaction is only slightly

stereoselective in the case of complex 31e.

We next studied systems with ligands 21f and 25f, with the

phosphine bearing the 2-(1′-naphthyl)phenyl arm (Scheme

18).

The same coordination and tethering studies were then

performed with 2-m-terphenylyl-containing phosphines 21e

and 25e (Scheme 17).

Orange complexes 26e and 28e were obtained straightfor-

wardly following the standard coordination procedure. Their

characterization conﬁrmed the expected structure, showing

unremarkable spectroscopic features. The tethering reaction of

The free ligands were present as mixtures of two

atropisomers, as discussed before; whose ratios were 1:1 and

1:1.2 for compounds 21f and 25f, respectively. Upon

coordination, untethered orange complexes 26f and 28f were

also present as isomeric mixtures with approximate 1:1.2 and

1:2.0 isomeric ratios, respectively. The tethered complexes 29f

and 31f were prepared under the standard conditions. Unlike

the red to brown color of all other Ru complexes described in

this paper, 29f was purple and in solution had an unexpected

26e and 28e aﬀorded complexes 29e and 31e, respectively, as

dark red solids. The most interesting feature of these

compounds is that they were found to be present as a mixture

of two isomers in solution according to NMR. Hence, two

peaks separated by less than 1 ppm were observed in the

6

sensitivity toward oxygen. This may be due to a weaker η -

coordination of the naphthyl group compared the phenyl

9k

group in combination of the lower basicity of the phosphinite

ligand. This compound is present as a mixture of two isomers in

solution, in an approximate 1:1.2 ratio. As expected, two sets of

3

1

P{ H} spectra and two sets of four signals (a singlet, two

6

doublets, and a triplet) could be observed in the η -arene

coordination region of the H spectra. The number and

1

6

1

three signals in the η -arene coordination region of the H

multiplicities pattern of each set ﬁts well with the meta

substitution of the coordinated phenyl ring of the phosphine.

The two isomers arise from the nonsymmetric nature of the 2-

m-terphenylyl arm of the phosphine, which originates a

stereogenic plane upon tethering. Integration of NMR peaks

showed that the isomeric ratios were approximately 1:1 and

spectra of 29f and 31f were found.

Finally, we carried out the same kind of study with ligands

21g and 25g, with the phosphine bearing the 2-(2′-naphthyl)-

phenyl fragment (Scheme 19).

Complexes 26g and 28g, obtained by the standard method,

were present as single species in solution according to NMR.

The molecular structure of 26g could be obtained by single-

crystal X-ray diﬀraction methods (Scheme 20).

1

:1.3 for compounds 29e and 31e, respectively. These ratios

show that, despite the mild conditions required to tether

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1

0

Scheme 20. ORTEP Representation (Thermal Ellipsoids

Drawn at 50% Probability Level, H Atoms Removed for

Clarity) of 26g

up to 45% ee were reached at reﬂux of isopropanol, whereas

with trialkylphosphines prepared by the Evans method, up to

59% ee could be attained at 40 °C. In the studies with

a

9r

trialkylphosphines, it was found that, when the reactions were

carried out at 40 °C, tethering increased the activity of the

precursors probably due to their higher robustness and the

tendency to mainly form a monohydride species after

activation. The enantioselectivity did not improve in the

tethered complexes and was moderate only when the arm of

the phosphine contained a bulky aryl group.

To further study the factors aﬀecting activity and selectivity

in asymmetric transfer hydrogenation, the new Ru complexes

described in this paper were employed as catalytic precursors in

the reduction of acetophenone (Scheme 21).

a

Scheme 21. Ru-Catalyzed Transfer Hydrogenation of

Acetophenone

Distances (Å) and angles (deg): Ru(1)−Cl(1), 2.4016(9); Ru(1)−

Cl(2), 2.3930(9); Ru(1)−P(1), 2.3246(9); P(1)−C(9), 1.834(4);

P(1)−C(25), 1.815(4); P(1)−O(3), 1.607(3); C(14)−C(15),

1

Ru(1)−Cl(1), 93.20(3); P(1)−Ru(1)−Cl(2), 86.84(3); Cl(1)−

Ru(1)−Cl(2), 89.29(3); C(9)−C(14)−C(15)−C(16), 118.1(4).

.498(5); Ru(1)−C

, 2.199; Ru(1)−center , 1.703; P(1)−

arene,mean

arene

The structure conﬁrms the identity of the complex and the R

absolute conﬁguration of phosphinite 21g. It is very similar to

the structures of 26d and 27d, with the carboxylate group of

the coordinated arene located over the two Cl atoms and in a

trans relative position to the phosphinite ligand. The phenyl

and the 2-naphthyl groups of the phosphinite ligand form an

angle of 118°.

Transfer hydrogenation experiments were carried out in

reﬂuxing (82 °C) isopropanol, which acted both as a hydrogen

donor and a solvent in the presence of 0.5% of Ru precursor

and 2.5% of potassium tert-butoxide as base. The catalytic

precursors were activated for 15 min prior to the introduction

of the substrate acetophenone to generate the catalytically

9

r,38

The tethering reaction of 26g and 28g was also successful,

aﬀording complexes 29g and 31g, respectively, as brown solids.

Once again, the duplication of peaks seen in NMR showed that,

in solution, they were present as a mixture of two isomers with

ratios of 1:1.6 and 1:1 for 29g and 31g, respectively.

active ruthenium hydride species.

The obtained results at

selected times are given in Table 1, while the full table of results

can be found in the Supporting Information.

In order to discuss the eﬀect of tethering on the catalytic

performance with the other precursors, it is important to know

3

1

6

Interestingly, the P{ H} chemical shift diﬀerence between

the two isomers of each compound were considerably larger

than those observed for the previous isomeric mixtures, being 3

ppm for 29g and more than 10 ppm in the case of 31g. In the

if the tethering of η -methyl benzoate complexes takes place

under catalytic conditions. Therefore, precursor 11c (δ =

P

+21.8 ppm) was suspended in isopropanol (in the absence of

potassium tert-butoxide) and heated to 82 °C for 1 h protected

1

H, two sets of three signals (a singlet and two doublets) could

from light, leading to tethered complex 15c (δ = +42.9 ppm)

P

6

31

1

be observed in the η -arene coordination region, which ﬁts with

according to P{ H} NMR spectroscopy. This means that it is

possible that catalysts, which are hydridic Ru species formed

after activation with potassium tert-butoxide, also suﬀer the

tethering reaction.

the expected structure.

Transfer Hydrogenation. The Ru-catalyzed enantioselec-

tive reduction of ketones to alcohols under transfer hydro-

genation conditions, and hence avoiding the manipulation of

To get some insight into the species formed in the activation

gaseous H , is one of the most actively studied reactions in

step, p-cymene complex 11c′ (δ = +21.3 ppm) was treated

2

P

1a,33

enantioselective catalysis for the past decades.

As a result,

with 5 equiv of potassium tert-butoxide in reﬂuxing isopropanol

highly active systems with very high enantioselectivities have

for 15 min. No trace of starting material could be observed in

5

c,15a,b,16c,33b,34

6

31

1

been developed.

Typically, the catalytic precur-

the P{ H} NMR spectrum, which showed a major broad peak

1

sors are Ru(II)-η -arene complexes with chiral polydentate

nitrogen ligands, sometimes combined with chiral or achiral

phosphorus-based ligands. Recently, some of these systems

incorporate tethered ligands, which have led to improved

at +41.8 ppm. H NMR spectrum of the hydride region showed

two doublets at −9.79 (J = 52.8 Hz) and −9.13 (J = 44.8 Hz),

which collapsed into two singlets upon phosphorus decoupling.

3

8,39

These data ﬁt well

with the formation of the monohydride

5

c,15a,b,16c,34g,h,35

6

performances in some cases.

complex [RuClH(η -p-cymene)(P(2-biphenylyl)MePh)],

present as a pair of diastereomers due to the generation of a

stereogenic Ru atom. In addition to this product, two doublets

of doublets at −7.85 (J = 56.8, 11.4 Hz) and −8.01 (J = 58.0,

Complexes of the type [RuCl (η -arene)P] (P = mono-

2

phosphorus ligand) furnish also catalytically active systems, but

they have been scarcely used in the reaction despite their

straightforward synthesis and ease of manipulation. There are

literature examples of transfer hydrogenation reactions using

1

7.2 Hz) were also observed in the H NMR spectrum, which

collapsed to two doublets still having the small coupling

3

6

37

this kind of precursors with either p-cymene or benzene as

constants upon phosphorus decoupling. This species could

6

η -coordinated arene. While these studies used precursors

correspond to [RuH (η -p-cymene)(P(2-biphenylyl)MePh)], a

2

based on achiral phosphines, we focused on similar systems but

using chiral P-stereogenic ligands. With diarylphosphines

compound with two diastereotopic hydride ligands.

The same experiment was carried out with complex methyl

prepared by the Juge−

́

Stephan method, full conversions and

benzoate complex 11c (δ = +21.7 ppm). In this case, the

P

9

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Table 1. Hydrogen Transfer of Acetophenone with Ru Precursors

a

b

c

entry

precursor

conversion (1 h)/%

conversion (3 h)/%

ee/%

<5

1

2

3

4

5

6

7

8

9

6a

44

28

64

29

40

25

39

82

45

13

56

40

36

64

25

44

89

80

36

21

9

72

62

94

57

76

60

79

97

85

58

82

71

68

84

46

96

>99

70

56

29

42

29

69

29

47

35

95

70

65

85

62

97

38

97

34

66

51

57

33

6b

6c

23 (R)

<5

5a

5b

<5

7a

<5

7b

<5

9c

18 (R)

15 (R)

7 (R)

26 (R)

10 (R)

22 (R)

45 (R)

<5

10c

10c′

11c

11c′

12c

12c′

13c

14c

15c

16c

17c

26d

26d′

27d

27d′

28d

28d′

29d

30d

31d

26e

28e

29e

31e

26f

28f

29f

31f

26g

28g

29g

31g

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

1

0a

d

22 (R)

20 (R)

22 (S)

<5

1

0b

<5

16

11

45

12

25

13

73

33

31

59

33

73

10

76

14

32

22

27

28

<5

12 (R)

10 (S)

<5

16 (R)

10 (S)

13 (R)

8 (S)

<5

47 (S)

<5

42 (S)

<5

16 (R)

<5

10 (R)

a

Catalytic conditions: Ru complex (0.02 mmol) and t-BuOK (0.1 mmol) dissolved in 25 mL of i-PrOH and activated at 82 °C during 15 min before

b

c

adding acetophenone (4.0 mmol). Conversion of starting acetophenone. Enantiomeric excess at the highest conversion (see the Supporting

Information). The absolute conﬁguration was erroneously reported to be S in ref 10a.

d

probable monohydride species could be detected both in the

benzoate lead to faster catalysts compared to those with p-

cymene (entries 11 vs 12, 20 vs 21, and 24 vs 25), although the

ligand P(2-biphenylyl)(i-Pr)Ph is an exception (entries 13 vs

14).

In the case of precursors with phosphines containing a 2-

biphenylyl or 2-terphenylyl moiety (entries 3, and 8−32), for

each ligand, the tethered complex is usually slightly faster

compared to the untethered counterpart. In contrast, very

similar rates are found for both types of complexes in the case

of precursors based on 2-(naphthyl)phenyl-containing phos-

phines (entries 33−40).

The enantioselectivities are, in general, low or very low, with

some exceptions (entries 3, 8, 14, 33, and 35). In case of

induction, phosphinites with an R absolute conﬁguration as free

ligands give 1-phenylethanol enriched in the S enantiomer,

whereas phosphines, with an S absolute conﬁguration, give

3

1

P{ H} NMR spectrum (δ = +40.0 ppm) and in the H NMR

P

spectrum of the hydride region, which showed two doublets at

−

9.06 (J = 52.8 Hz) and −9.13 (J = 42.8 Hz) that collapsed

into singlets upon phosphorus decoupling. No evidence of

dihydride species could be detected.

All the precursors were active in the reaction, reaching almost

complete conversions after 24 h (see the Supporting

Information). In spite of this, notable diﬀerences in rates

were found when analyzing the conversions at shorter reaction

times. Although there is not a general pattern, some tendencies

can be uncovered comparing the same ligand in the diﬀerent

complexes or the same kind of complexes with diﬀerent ligands.

Comparison of the results with pairs of untethered

precursors with the same ligand but diﬀerent coordinated

arene shows that, in general, complexes bearing methyl

9

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Organometallics

Article

more (R)-1-phenylethanol. In Table 1, the enantioselectivities

are only given at the highest conversion for each precursor (see

the Supporting Information). It has been observed that, in most

cases, the ee values decrease over time, being around 5% higher

at 1 h of reaction time than the values of the table. In the case

of methyl benzoate precursors, this fact could be explained

because of the ongoing tethering of the precursor during the

catalysis, leading to the tethered complex, which is usually less

enantioselective.

EXPERIMENTAL SECTION

■

General Data. All compounds were prepared under a puriﬁed

nitrogen atmosphere using standard Schlenk and vacuum-line

techniques. The solvents were puriﬁed by a Puresolve (Innovative

4

0

Technologies) solvent puriﬁcation system or by standard procedures

1

13

1

31

1

and kept under nitrogen. H, C{ H}, and P{ H}, and HSQC

1

13

H− C NMR spectra were recorded using a Varian Mercury 400

MHz and Varian Inova 300 MHz spectrometers using CDCl₃as

solvent unless otherwise speciﬁed. Chemical shifts are reported

downﬁeld from standards. The protons of the BH of phosphine-

3

The interpretation and rationalization of the catalytic results

in relation to the catalytic precursor employed is complicated

boranes group appeared in the aliphatic region of the spectra as very

broad bands and have not been assigned. IR spectra were recorded

with a ThermoNicolet avatar 330 spectrometer in KBr, and the main

absorption bands are expressed in cm . Mass analyses were carried

out at the Servei d’Espectrometria de Masses de la Universitat de

Barcelona, using an Agilent Technologies LC/MSD-TOF instrument.

Optical rotations were measured with a PerkinElmer 241MC

polarimeter at 23 °C using a sodium lamp at the sodium D-line

wavelength (589.592 nm). The solvent and the concentration (g/100

mL) for each compound are indicated in parentheses. Elemental

6

due to the simultaneous tethering of the η -methyl benzoate

−

1

complexes during the catalytic runs. In spite of this, in general,

the enantioselectivity tends to be slightly higher with the

untethered complexes.

CONCLUSIONS

■

In this paper, a series of optically pure P-stereogenic

diarylphosphine ligands designed to form tethered Ru

complexes have been described. Their preparation following

́

analyses (C, H, N) were performed at the Centres Cientiﬁcs i

Tecnologics (CCiT) of the Universitat de Barcelona. Transfer

̀

hydrogenation reactions were analyzed by GC in a Hewlett-Packard

5890 Series II chromatograph, equipped with a chiral Chiraldex DM

capillary column (30 m long and 0.25 mm of diameter) with He as a

carrier gas and a FID detector. UV−vis spectra were recorded in an

deprotonation of optically pure methylphosphine-boranes and

6

their coordination to [RuCl (η -arene)] units have been carried

2

out smoothly. The diaryl nature of the phosphines has

complicated the thermal displacement of the aryl group to

form the tethered complexes, in contrast to related

−

4

HP 8452A spectrophotometer of 2.5 × 10 M dichloromethane

−1

solutions of the complexes. λ are expressed in nm and ε in M

max

−1

cm . Photochemistry experiments were performed using a MNAAX-

9r

1

2b

12

trialkylphosphines. Indeed, it has been impossible to displace

the p-cymene fragment by the incoming aryl group of the

phosphine under a variety of conditions, which forced us to

move to the more labile methyl benzoate fragment. With this

303 collimated xenon light source. Phosphine-boranes 1a,

1b,

12b

1

2b

26

25a

12b

1c,

18, P(2-biphenylyl)PhR (R = OMe, Me,

i-Pr , and

2

5b

10b

10b,27a

Fc ), 21d,

24d,

and 25d;

aryl bromides ArBrd,

2

7b

27c

27d

9i

ArBre,

ArBrf , and ArBrg

and Ru precursor Dim2 were

prepared as described elsewhere, whereas other reagents were used as

received from commercial suppliers.

modiﬁcation, the synthesis of the expected tethered complexes

6

5

a,b from η -methyl benzoate complexes 6a,b has been

(

S)-(9-Phenanthryl)phenyl(3-phenyl-2,2-dimethyl-2-

accomplished, but the tethering of complexes 7a,b has not

been successful under similar conditions.

silapropyl)phosphine-borane, 2′a. Phosphine-borane 1a (314 mg,

1 mmol) was dissolved in 5 mL of THF, and the solution was cooled

down to −78 °C. sec-Butyllithium (1 mL of a 1.3 M solution, 1.3

mmol) was added by syringe, and the mixture was stirred for 2 h at

Unexpectedly, it has been found that, with phosphine 2c,

with a 2-biphenylyl substituent, the tethering reaction is very

much favored by the phenyl ring of this substituent, taking

place at room temperature in the presence of light. It has been

found that this reaction is very general with phosphines with

unsubstituted (c), monosubstituted (d, e), and even fused (f, g)

−

78 °C. After this time, benzylchlorodimethylsilane (0.235 mL, 1.3

mmol) was rapidly added by syringe and the mixture was left to slowly

reach room temperature. The hydrolysis was carried out by carefully

adding HCl 1 M. Most of the THF was removed under vacuum, the

resulting mixture was extracted with dichloromethane (3 × 20 mL),

and the combined organic phases were washed with water, dried with

anhydrous Na SO , and ﬁltered. Removal of all volatiles under vacuum

2

-biphenylyl groups. In the case of nonsymmetrically

substituted 2-biphenylyl fragments (e, f, g), the reaction yields

a pair of diastereomers due to the formation of a stereogenic

plane upon tethering. For the systems studied here, the

stereoselectivity of the tethering reaction is very low.

The Ru complexes described here have been used as

precursors in Ru-catalyzed transfer hydrogenation of acetophe-

none, giving full conversions to the reduction product (1-

phenylethanol) after several hours at reﬂux of isopropanol (82

2

4

left a white residue, which was puriﬁed by column chromatography

ﬂash SiO , hexane:ethyl acetate 95:5), to yield the title product as a

(

2

colorless oil. Yield: 381 mg (63%).

1

H NMR (400.1 MHz): −0.25 (s, 3H), −0.12 (s, 3H), 1.76 (t,

²J

= 13.6, 1H), 1.97 (t, J , J = 16, 13.6, 1H), 2.04 (d, J

2

=

PH+HH

PH

HH

2

13.6, 1H), 2.09 (d, J = 13.6, 1H), 6.90 (d, J = 7.2, 2H), 7.06 (t, J =

HH

7.4, 1H), 7.17 (t, J = 7.6, 2H), 7.34−7.42 (m, 4H), 7.57−7.62 (m,

3

H), 7.69 (t, J = 7.5, 1H), 7.78 (t, J = 7.5, 1H), 7.87 (d, J = 8.0, 1H),

.01 (d, J = 8.0, 1H), 8.54 (d, J = 16.0, 1H), 8.68−8.74 (m, 2H).

8

°

C). The fastest and the only slightly enantioselective systems

13

1

3

C{ H} NMR (101 MHz): −1.87 (d, J = 1.9, CH ), −1.72 (d, J

PC

3

PC

are those with 2-biphenylyl-containing ligands, although the

rates and enantioselectivities strongly depend on the sub-

stituents of the phosphine ligand. Only in the case of precursors

1

3

=

1

1.9, CH ), 10.9 (d, J = 25.4, CH ), 26.9 (d, J = 3.9, CH₂),

3 PC 2 PC

31

1

22.6−139.2 (C, CH, Ar). P{ H} NMR (121 MHz): +14.5 (s, br).

Anal.: calcd. for C H BPSi: C 77.92%, H 6.98%; found C 77.44%, H

30

32

26f and 29f, with the ligand P(2-(1′-naphthyl)phenyl)(OMe)-

7.38%. [α] (c = 0.75, CH Cl ): −9.8°.

D

2

Ph (21f), a moderate enantioselectivity of around 45% has been

found. The tethering of the phosphine ligand does not aﬀect in

a predictable way the catalytic properties of the precursors. It is

very likely that the tethering reaction occurs under catalytic

conditions, and since the tethered complexes are not more

selective in the transfer hydrogenation, this process does not

improve the obtained enantioselectivities.

(S)-(1-Naphthyl)phenyl(3-phenyl-2,2-dimethyl-2-silapropyl)-

phosphine-borane, 2′b. The preparation was analogous to that of

2

′a. Starting from 1b (264 mg, 1 mmol), the title product was

obtained as a colorless oil. Yield: 274 mg (64%).

1

H NMR (300.0 MHz): −0.28 (s, 3H), −0.15 (s, 3H), 1.71 (t,

2_J

2

= 13.8, 1H), 1.92 (t, J

= 16.2, 1H), 2.02 (s, 2H), 6.90 (d,

PH+HH

J = 6.9, 2H), 6.97−7.60 (m, 10H), 7.83 (d, J = 8.4, 1H), 7.88 (d, J =

8.4, 1H), 8.02 (d, J = 8.1, 1H), 8.17 (dd, J = 7.2, 1.2, 1H), 8.22 (dd, J =

9

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1

3

1

3

7

1

.2, 1.2, 1H). C{ H} NMR (101 MHz): −2.0 (d, J = 2.0, CH ),

(S)-(1-Naphthyl)phenyl(3-phenyl-2,2-dimethyl-2-silapropyl)-

phosphine, 2b. The procedure was the same as that used to prepare

2a. Starting from phosphine-borane 2′b (412 mg, 1 mmol), the title

product was isolated as a white pasty solid. Yield: 346 mg (87%).

PC

3

1

3

.8 (d, J = 1.6, CH ), 11.0 (d, J = 25.5, CH ), 26.8 (d, J = 3.7,

PC

3

PC

2

PC

3

1

CH ), 124.0−139.4 (C, CH, Ar). P{ H} NMR (121 MHz): +13.8

2

(

4

d, br, J ≈ 53). HRMS(ESI): calcd. for C H BNSiP ([M] + NH ),

26

34

4

1

30.2285; found, 430.2284. [α] (c = 1.04, CH Cl ): −22.8°.

H NMR (400.1 MHz): −0.02 (s, 3H), 0.00 (s, 3H), 1.56 (s, 2H),

D

2

(

S)-(2-Biphenylyl)phenyl(3-phenyl-2,2-dimethyl-2-

2.18 (s, 2H), 7.06−7.13 (m, 2H), 7.19 (tt, J = 7.4, 1.2, 1H), 7.29−7.33

(m, 2H), 7.36−7.40 (m, 3H), 7.55−7.61 (m, 5H), 7.72 (td, J = 6.8,

silapropyl)phosphine-borane, 2′c. The preparation was analogous

to that of 2′a. Starting from 1c (290 mg, 1 mmol), the title product

was obtained as a colorless oil. Yield: 290 mg (66%).

1

3

1

1.2, 1H), 7.93−7.97 (m, 2H), 8.69−8.73 (m, 1H). C{ H} NMR

1

(101 MHz): −2.3 (s, CH ), −2.2 (s, CH ), 12.4 (d, J = 30.0, CH ),

3

PC

2

1

2

3

31

1

H NMR (300.0 MHz): −0.17 (s, 6H), 0.96 (t, J

= 14.0, 1H),

26.5 (d, J = 4.5, CH ), 124.0−140.7 (C, CH, Ar). P{ H} NMR

PH+HH

PC

2

1

.16 (t, J

= 14.0, 1H), 2.02 (d, J = 13.6, 1H), 2.09 (d, J =

(121 MHz): −35.0 (s).

PH+HH

HH

3.6, 1H), 6.93 (d, J = 8.0, 2H), 7.04−7.31 (m, 12H), 7.34−7.40 (m,

(S)-(2-Biphenylyl)phenyl(3-phenyl-2,2-dimethyl-2-

silapropyl)phosphine, 2c. The procedure was the same as that used

to prepare 2a. Starting from phosphine-borane 2′c (438 mg, 1 mmol),

the title product was obtained as a white pasty solid. Yield: 347 mg

(82%).

13

1

H), 7.45−7.54 (m, 3H), 8.19 (ddd, J = 14.1, 6.9, 2.1, 1H). C{ H}

3

NMR (101 MHz): −2.0 (d, J = 1.7, CH ), −1.9 (d, J = 2.7,

PC

3

PC

1

3

CH ), 8.4 (d, J = 25.3, CH ), 26.8 (d, J = 3.7, CH ), 124.1−

3

PC

2

PC

2

3

1

46.6 (C, CH, Ar). P{ H} NMR (121 MHz): +16.8 (s, br).

1

4

HRMS(ESI): calcd. for C H BNSiP ([M] + NH ), 456.2442; found,

H NMR (400.1 MHz): −0.30 (d, JPH = 0.8, 3H), −0.25 (d, JPH

=

28

36

4

2

4

56.2440. [α] (c = 1.05, CH Cl ): +12.5°.

0.8, 3H), 1.19 (t, J

= 13.6, 1H), 1.23 (t, J

= 13.5, 1H),

D

2

PH+HH

2

(

S)-(2-(2-Naphthyl)ethyl)(9-phenanthryl)phenylphosphine-

1.89 (d, J = 13.5, 1H), 1.93 (d, J = 13.5, 1H), 6.87−6.90 (m,

HH

borane, 3′a. Phosphine-borane 1a (314 mg, 1 mmol) was dissolved

in 10 mL of THF and cooled down to −78 °C. sec-Butyllithium (1 mL

of a 1.3 M solution, 1.3 mmol) was added by syringe, and the mixture

was stirred for 2 h at −78 °C. In parallel, a solution of (2-

bromomethyl)naphthalene (258 mg, 1.3 mmol) in 10 mL of THF was

cooled −78 °C. The ﬁrst solution was added over the second one via

cannula, and the mixture was left to slowly reach room temperature.

The hydrolysis was carried out by carefully adding HCl 1 M. Most of

the THF was removed under vacuum, the resulting mixture was

extracted with dichloromethane (3 × 20 mL), and the combined

organic phases were washed with water, dried with anhydrous Na SO ,

2H), 7.03−7.08 (m, 1H), 7.15−7.26 (m, 10H), 7.29−7.35 (m, 3H),

13 1

7.36 (td, J = 7.3, 1.7, 1H), 7.41−7.45 (m, 1H). C{ H} NMR (101

1

MHz): −2.5 (s, CH ), −2.4 (s, CH ), 13.1 (d, J = 32.0, CH ), 26.5

3

PC

2

3

31

1

(d, J = 4.7, CH ), 123.9−147.6 (C, CH, Ar). P{ H} NMR (121

PC

2

MHz): −29.9 (s).

(S)-(2-(2-Naphthyl)ethyl)(9-phenanthryl)phenylphosphine,

3a. The procedure was the same as that used to prepare 2a. Starting

from phosphine-borane 3′a (454 mg, 1 mmol), the title product was

isolated as a white pasty solid. Yield: 400 mg (91%).

1

H NMR (400.1 MHz): 2.53−2.74 (m, 2H), 2.91−3.14 (m, 2H),

7.30−7.34 (m, 3H), 7.42−7.48 (m, 3H), 7.52−7.59 (m, 3H), 7.61−

2

4

and ﬁltered. Removal of all volatiles under vacuum left a white residue,

which was puriﬁed by column chromatography (SiO₂ﬂash,

hexane:ethyl acetate 90:10). Yield: 372 mg (82%).

H NMR (300.0 MHz): 2.76−3.11 (m, 4H), 7.19 (dd, J = 8.4, 1.8,

H), 7.36−7.50 (m, 7H), 7.60−7.84 (m, 8H), 7.98 (d, J = 8.1, 1H),

.01 (dd, J = 7.8, 1.5, 1H), 8.53 (d, J = 15.6, 1H), 8.67 (d, J = 8.0, 1H),

.71 (d, J = 8.0, 1H). C{ H} NMR (101 MHz): 27.6 (d, J = 34.6,

CH ), 29.4 (d, J = 1.5, CH ), 122.6−139.2 (C, CH, Ar). P{ H}

NMR (121 MHz): +16.8 (s, br). HRMS(ESI): calcd. for C H P (M

7.69 (m, 4H), 7.75−7.91 (m, 5H), 8.53 (ddd, J = 10.8, 6.4, 1.6, 1H),

13

1

2

8.66−8.74 (m, 2H). C{ H} NMR (101 MHz): 29.6 (d, J = 13.0,

PC

31

1

CH ), 32.5 (d, J = 18.9, CH ), 122.5−140.1 (C, CH, Ar). P{ H}

2

PC

2

1

NMR (121 MHz): −25.5 (s).

1

8

(S)-(1-Naphthyl)(2-(2-naphthyl)ethyl)phenylphosphine, 3b.

The procedure was the same as that used to prepare 2a. Starting

from phosphine-borane 3′b (404 mg, 1 mmol), the title product was

isolated as a white pasty solid. Yield: 374 mg (96%).

1

3

1

PC

31

2

1

2

PC

2

1

32

26

H NMR (400.1 MHz): 2.50−2.64 (m, 2H), 2.90−3.03 (m, 2H),

−

BH ), 441.1772; found, 441.1764. [α] (c = 0.95, CH Cl ): +37.9°.

7.31−7.52 (m, Ar, 10H), 7.60−7.63 (m, Ar, 2H), 7.74−7.84 (m, Ar,

3

D

2

13

1

(

S)-(1-Naphthyl)(2-(2-naphthyl)ethyl)phenylphosphine-bor-

ane, 3′b. The preparation was analogous to that of 3′a. Starting from

b (264 mg, 1 mmol), the title product was obtained as a white solid

after puriﬁcation by recrystallization in dichloromethane/ethanol and

washing with pentane. Yield: 307 mg (79%).

4H), 7.86−7.89 (m, Ar, 2H), 8.55−8.59 (m, Ar, 1H). C{ H} NMR

2

1

(

1

101 MHz): 29.6 (d, J = 13.1, CH ), 32.5 (d, J = 18.9, CH₂),

PC 2 PC

31

1

25.1−140.1 (C, CH, Ar). P{ H} NMR (121 MHz): −27.6 (s).

Dichloro(η -p-cymene)[(R)-(9-phenanthryl)phenyl(3-phenyl-

6

2,2-dimethyl-2-silapropyl)phosphine]ruthenium(II), 4a. Phos-

phine 2a (448 mg, 1 mmol) was dissolved in 20 mL of

dichloromethane, and Ru dimer Dim1 (245 mg, 0.4 mmol) was

added. The mixture was stirred for 1 h and brought to dryness under

vacuum. The residue was recrystallized in dichloromethane/hexane to

aﬀord the title product as a red solid. Yield: 436 mg (71%).

1

H NMR (400.1 MHz): 2.67−2.80 (m, 1H), 2.82−3.05 (m, 3H),

7

.20 (dd, J = 8.4, 1.8, 1H), 7.35−7.54 (m, 8H), 7.55−7.67 (m, 3H),

.68−7.73 (m, 2H), 7.74−7.81 (m, 1H), 7.89 (d, J = 8.1, 1H), 7.98 (d,

J = 8.2, 1H), 8.03 (d, J = 8.1, 1H), 8.15 (ddd, J = 13.8, 6.9, 1.2, 1H).

13

1

C{ H} NMR (101 MHz): 27.8 (d, J = 34.9, CH ), 29.3 (s, CH ),

24.0−138.7 (C, CH, Ar). P{ H} NMR (121 MHz): +16.0 (s, br).

HRMS(ESI): calcd. for C H BNP (M + NH ), 422.2203; found,

PC

2

3

1

3

1

H NMR (400.1 MHz): −0.70 (s, 3H), −0.24 (s, 3H), 1.03 (d, J

HH

3

2

= 7.2, 3H), 1.05 (d, J = 6.8, 3H), 1.69 (s, 3H), 1.89 (d, J = 13.4,

1H), 2.01 (d, J = 13.4, 1H), 2.04 (m, 1H), 2.65 (heptaplet, J

7.2, 1H), 2.80 (t, J

4.96 (m, 2H), 5.14 (d, J = 6.0, 1H), 7.04 (d, J = 7.2, 2H), 7.19−7.23

28

30

4

HH

2

3

4

22.2219.

(

=

HH

2

S)-(9-Phenanthryl)phenyl(3-phenyl-2,2-dimethyl-2-

= 14.4, 1H), 4.22 (d, J = 4.4, 1H), 4.94−

PH+HH

PH

2

silapropyl)phosphine, 2a. Phosphine-borane 2′a (462 mg, 1 mmol)

was dissolved in 5 mL of morpholine, and the solution was stirred at

room temperature for 14 h. Excess morpholine was removed under

vacuum, and the gummy residue was puriﬁed by column

chromatography (Al O , toluene) to yield the title product as a

PH

(m, 3H), 7.29−7.35 (m, 4H), 7.43 (t, J = 7.6, 1H), 7.60 (d, J = 6.8,

1H), 7.62−7.70 (m, 3H), 7.80 (td, J = 7.4, 1.2, 1H), 7.86 (d, J = 12.8,

1H), 8.24 (d, J = 8.0, 1H), 8.76 (t, J = 9.0, 2H). ¹³C{ H} NMR (101

MHz): −2.0 (s, CH ), −1.6 (s, CH ), 14.5 (s, br, CH ), 17.7 (s, CH ),

1

2

3

2

3

1

dense, colorless oil. Yield: 403 mg (90%).

H NMR (400.1 MHz): −0.09 (d, J = 0.4, 3H), −0.06 (d, J

.8, 3H), 1.491 (d, J = 14.1, 1H), 1.494 (d, J = 14.1, 1H), 2.11

2

1.3 (s, CH ), 22.7 (s, CH ), 27.6 (d, J = 3.8, CH ), 30.3 (s, CH),

3 3 PC 2

1

4

=

PH

82.6 (s, CH), 88.4 (s, CH), 88.5 (s, CH), 92.0 (s, CH), 95.3 (s, C),

2

31

1

0

(

6

7

PH PH

107.1 (s, CH) 122.7−140.0 (C, CH, Ar). P{ H} NMR (121 MHz):

s, 2H), 6.96−6.99 (m, 2H), 7.08 (tt, J = 7.02, 1.2, 1H), 7.20 (t, J =

+

21.9 (s). Anal.: calcd. for C H Cl PRuSi: C 63.65%, H 5.74%;

40 43 2

.5, 2H), 7.24−7.27 (m, 3H), 7.50−7.54 (m, 3H), 7.59−7.63 (m, 2H),

.67 (td, J = 7.2, 1.6, 1H), 7.87 (dd, J = 7.6, 1.6, 1H), 7.89 (d, J = 5.6,

H), 8.54 (ddd, J = 8.0, 4.8, 1.2, 1H), 8.66 (d, J = 10.0, 1H), 8.69 (d, J

found C 61.95%, H 6.26%.

6

Dichloro(η -methyl benzoate)[(R)-(9-phenanthryl)phenyl(3-

phenyl-2,2-dimethyl-2-silapropyl)phosphine]ruthenium(II),

6a. Phosphine 2a (448 mg, 1 mmol) was dissolved in 20 mL of

dichloromethane, and Ru dimer Dim2 (247 mg, 0.4 mmol) was added.

The mixture was stirred for 1 h protected from light and ﬁltered to

remove any excess of Dim2, and the ﬁltrate was brought to dryness

1

3

1

3

=

−

4

8.0, 1H). C{ H} NMR (101 MHz): −2.17 (d, J = 2.8, CH ),

PC

3

1

3

2.11 (d, J = 3.0, CH ), 12.4 (d, J = 30.7, CH ), 26.5 (d, J =

PC

3

PC

2

PC

3

1

.6, CH ), 122.5−140.0 (C, CH, Ar). P{ H} NMR (121 MHz):

2

−

32.9 (s).

9

86

DOI: 10.1021/acs.organomet.5b00018

Organometallics 2015, 34, 973−994

Organometallics

Article

6

under vacuum. The residue was recrystallized in dichloromethane/

Dichloro(η -methyl benzoate)[(R)-(1-naphthyl)(2-(2-

naphthyl)ethyl)phenylphosphine]ruthenium(II), 7b. The proce-

dure was the same as that used to prepare 6a. Starting from phosphine

3b (390 mg, 1 mmol), the title product was obtained as a brownish

solid. Yield: 399 mg (70%).

hexane to aﬀord the title product as a brown solid. Yield: 400 mg

(65%).

IR (ν): 3073, 2948, 2878, 1728 (CO), 1492, 1433, 1291, 1269,

1

110, 830, 769, 751. H NMR (400.1 MHz): −0.59 (s, 3H), −0.25 (s,

1

2

IR (ν): 3073, 2951, 1728 (CO), 1433, 1270, 1110, 771. H NMR

3

H), 1.82 (d, J = 13.5, 1H), 1.99 (d, J = 13.5, 1H), 2.24 (dd,

HH HH

2

(300.0 MHz): 2.47 (s, br, 1H), 2.87 (m, br, 1H), 3.04 (m, br, 1H),

J , J = 15.5, 11.7, 1H), 2.83 (t, J = 15.0, 1H), 3.97 (s, 3H),

PH

HH

PH+HH

3

.38 (m, 1H), 3.87 (s, 3H), 4.54 (m, br, 1H), 5.21−5.25 (m, 2H), 6.19

4

5

7

8

.06 (t, br, J = 5.4, 1H), 5.14 (td, J = 6.6, 0.9, 1H), 5.50 (t, J = 5.7, 1H),

.92 (t, J = 4.5, 1H), 6.52 (d, J = 6.6, 1H), 7.04 (d, J = 8.0, 2H), 7.15−

.20 (m, 3H), 7.26−7.32 (m, 5H), 7.47 (td, J = 8.1, 1.2, 1H), 7.66−

.72 (m, 3H), 7.80−7.86 (m, 1H), 8.11 (d, J = 13.5, 1H), 8.31 (d, J =

(d, J = 6.0, 1H), 6.46 (d, J = 5.4, 1H), 7.22 (dd, J = 8.4, 1.8, 1H),

7

.28−7.51 (m, 7H), 7.57 (td, J = 6.9, 0.9, 1H), 7.64−7.80 (m, 6H),

.98 (d, J = 8.1, 1H), 8.09−8.17 (m, br, 2H), 8.33 (d, J = 8.7, 1H).

7

13

1

2

1

3

1

C{ H} NMR (101 MHz): 29.0 (d, J = 27.3, CH ), 30.9 (d, J

=

PC

2

PC

.1, 1H), 8.78 (t, J = 6.6, 1H). C{ H} NMR (101 MHz): −1.9 (s,

1

4.6, CH ), 53.3 (s, CH ), 83.6 (s, CH), 86.5 (m, br, CH), 90.7 (s,

CH ), −1.7 (s, CH ), 15.2 (s, br, CH ), 27.2 (d, J = 3.5, CH ), 53.2

2 3

3

2

PC

2

CH), 92.6 (s, CH), 96.9 (s, CH), 124.7−139.1 (C, CH, Ar), 164.6 (s,

(

s, OCH ), 83.2 (s, CH), 89.1 (m, CH), 90.7 (m, CH), 91.3 (s, CH),

3

31

1

31

1

CO). P{ H} NMR (121 MHz): +23.3 (s). Anal.: calcd. for

9

8.4 (m, CH), 122.7−139.4 (C, CH, Ar), 165.2 (s, CO). P{ H}

C H Cl O PRu: C 61.90%, H 4.47%; found C 60.34%, H 4.62%.

36

31

2

NMR (121 MHz): +23.8 (s). HRMS(ESI): calcd. for C H -

38 41

6

Dichloro[κP-η -(R)-(9-phenanthryl)phenyl(3-phenyl-2,2-di-

methyl-2-silapropyl)phosphine]ruthenium(II), 5a. Complex 6a

385 mg, 0.5 mmol) was dissolved in 15 mL of dichloromethane and 1

Cl NO PRuSi (M + NH ), 774.1059; found, 774.1079.

2

4

6

Dichloro(η -methyl benzoate)[(R)-(1-naphthyl)phenyl(3-

(

phenyl-2,2-dimethyl-2-silapropyl)phosphine]ruthenium(II),

mL of THF, and the solution was introduced into a stainless steel

autoclave. The temperature was raised to 120 °C, and the mixture was

left stirring for 4 h. The autoclave was opened, and the solution was

brought to dryness. The brownish residue was recrystallized in

dichloromethane/hexane, leaving the title product as a brown solid

after washing it with pentane. Yield: 197 mg (62%).₁

6

b. The procedure was the same as that used to prepare 6a. Starting

from phosphine 2b (398 mg, 1 mmol), the title product was obtained

as a brown solid. Yield: 397 mg (69%).

IR (ν): 3055, 2952, 1728 (CO), 1434, 1292, 1273, 1110, 828,

1

7

(

70, 700. H NMR (300.0 MHz): −0.55 (s, 3H), −0.36 (s, 3H), 1.74

2

d, J = 13.5, 1H), 1.87 (d, J = 13.5, 1H), 2.17 (dd, J , J

=

HH

PH

HH

2

IR (ν): 3056, 1434, 1248, 1093, 840, 808, 749. H NMR (400.1

1

7

8

5.6, 12.3, 1H), 2.69 (t, J

= 15.3, 1H), 3.96 (s, 3H), 4.04 (s, br,

PH+HH

2

MHz): 0.58 (s, br, 3H), 0.67 (s, br, 3H), 1.37 (d, J = 14.4, 1H),

HH

H), 5.11 (dt, J = 4.8, 0.9, 1H), 5.38 (t, J = 6.0, 1H), 5.91 (t, J = 4.8,

H), 6.47 (d, J = 6.3, 1H), 6.94 (d, J = 7.4, 2H), 7.10 (tt, J = 7.2, 1.5,

H), 7.20−7.25 (m, 5H), 7.30−7.36 (m, 1H), 7.36−7.43 (m, 1H),

.47−7.58 (m, 3H), 7.78 (dd, J = 7.5, 1.2, 1H), 7.95 (d, J = 8.1, 1H),

2

1

.83 (t, J

= 16.8, 1H), 1.90 (d, J = 14.4, 1H), 2.38 (t, J =

PH+HH HH

1

2.4, 1H), 3.55 (s, br, 1H), 4.42 (s, br, 1H), 5.25 (d, J = 5.2, 1H), 6.11

(

m, br, 1H), 6.19 (m, br, 1H), 7.12−7.16 (m, 2H), 7.24 (t, J = 7.6,

1

3

1

1H), 7.55 (t, J = 7.6, 1H), 7.65−7.80 (m, 4H), 7.86 (t, J = 7.6, 1H),

.08 (d, J = 8.4, 1H), 8.21 (d, J = 8.7, 1H), C{ H} NMR (101

3

8.06 (d, J = 8.0, 1H), 8.32 (d, J = 12.4, 1H), 8.76−8.84 (m, 4H).

MHz): −1.7 (d, J = 0.6, CH ), −1.6 (d, J = 1.6, CH ), 11.4 (s,

PC

3

PC

3

13

1

3

C{ H} NMR (101 MHz): 0.6 (d, J = 3.4, CH ), 1.3 (d, J = 3.6,

1

PC

3

PC

CH ), 27.0 (d, J = 3.3, CH ), 53.2 (s, CH ), 83.4 (s, CH), 88.2 (s,

2

PC

2

3

1

3

CH ), 12.4 (d, J = 16.1, CH ), 17.2 (d, J = 4.5, CH ), 80.3 (s,

3

PC

2

PC

2

br, CH), 91.0 (s, CH), 91.3 (s, CH), 98.0 (s, br, CH), 124.2−139.3

3

1

CH), 85.8 (s, CH), 89.1 (s, CH), 95.7 (d, J = 11.6, CH), 99.7 (s, CH),

(

C, CH, Ar), 165.1 (s, CO). P{ H} NMR (121 MHz): +23.5 (s).

3

1

22.8−133.4 (C, CH, Ar). P{ H} NMR (121 MHz): +32.0 (s).

Anal.: calcd. for C H Cl O PRuSi: C 57.79%, H 4.99%; found C

34

35

2

HRMS(ESI): calcd. for C H PRuSi (M − 2Cl), 549.0735; found,

30

28

5

6.91%, H 5.42%.

6

549.0746.

Dichloro(η -methyl benzoate)[(R)-(2-biphenylyl)phenyl(3-

phenyl-2,2-dimethyl-2-silapropyl)phosphine]ruthenium(II),

c. The procedure was the same as that used to prepare 6a. Starting

6

Dichloro[κP-η -(R)-(1-naphthyl)phenyl(3-phenyl-2,2-dimeth-

yl-2-silapropyl)phosphine]ruthenium(II), 5b. The procedure was

the same as that used to prepare 5a. Starting from complex 6b (360

mg, 0.5 mmol), the desired product was obtained as a brown solid.

Yield: 190 mg (67%).

6

from phosphine 2c (424 mg, 1 mmol), the title product was isolated as

a brown solid. Yield: 402 mg (67%).

IR (ν): 3053, 3021, 2950, 2893, 1728 (CO), 1492, 1434, 1293,

1

IR (ν): 3054, 2951, 2888, 1507, 1434, 1252, 1093, 840, 808, 777,

1

275, 1110, 828, 769, 700, 509, 485. H NMR (400.1 MHz): −0.30 (s,

1

6

92, 459. H NMR (300.0 MHz): 0.49 (s, br, 3H), 0.54 (s, 3H), 1.35

2

3

H), −0.26 (s, 3H), 1.44 (dd, J , J = 19.6, 13.6, 1H), 1.92 (t,

2

PH

HH

(

d, J = 14.4, 1H), 1.76 (dd, J , J = 19.5, 14.1, 1H), 1.93 (dd,

2

HH PH HH

J

= 14.5, 1H), 1.93 (d, J = 13.2, 1H), 1.97 (d, J = 13.2,

2

PH+HH

HH

J , J = 14.4, 3.0, 1H), 2.32 (dd, J , J = 14.4, 11.4, 1H), 3.45

PH

HH

PH

HH

1

6

7

H), 3.91 (s, 3H), 5.06 (t, J = 6.0, 1H), 5.08 (t, J = 7.0, 1H), 5.31 (m,

H), 6.22 (d, J = 6.0, 1H), 6.39 (d, J = 5.6, 1H), 6.88 (d, J = 7.2, 2H),

.95 (d, J = 7.1, 2H), 7.00 (t, J = 7.6, 1H), 7.06−7.25 (m, 8 H), 7.27−

.35 (m, 1H), 7.37−7.52 (m, 4H), 8.32 (dd, J = 14.4, 7.6, 1H).

(s, br, 1H), 4.49 (s, br, 1H), 5.23 (d, J = 5.1, 1H), 6.10 (t, J = 6.3, 1H),

6

.19 (t, J = 5.7, 1H), 7.09−7.18 (m, 2H), 7.20−7.25 (m, 1H), 7.45−

7

.72 (m, 5H), 7.94 (d, J = 8.1, 1H), 8.03 (dd, J = 11.4, 6.9, 1H), 8.14

13

1

(d, J = 8.6, 1H), 8.77 (d, br, J = 8.4, 1H). C{ H} NMR (101 MHz):

3

1

P{ H} NMR (121 MHz): +24.1 (s). HRMS(ESI): calcd. for

3

1

0

.2 (d, J = 3.5, CH ), 1.2 (d, J = 3.6, CH ), 12.2 (d, J = 16.6,

PC 3 PC 3 PC

C H ClPO RuSi (M − Cl), 697.1026; found, 697.1020.

3

6

37

2

CH ), 17.3 (d, J = 4.5, CH ), 80.7 (s, br, CH), 85.6 (s, CH), 89.0

2 PC 2

6

Dichloro(η -methyl benzoate)[(R)-(2-(2-naphthyl)ethyl)(9-

(

s, br, CH), 95.8 (d, J = 11.3, CH), 99.2 (s, br, CH), 123.9−133.9 (C,

phenanthryl)phenylphosphine]ruthenium(II), 7a. The procedure

was the same as that used to prepare 6a. Starting from phosphine 3a

31 1

CH, Ar). P{ H} NMR (121 MHz): +30.8 (s). Anal.: calcd. for

C H Cl PRuSi: C 54.74%, H 4.77%; found C 55.07%, H 5.26%.

26

27

2

(

440 mg, 1 mmol), the title product was isolated as a brown solid.

6

Dichloro[κP-η -(R)-(2-biphenylyl)phenyl(3-phenyl-2,2-di-

methyl-2-silapropyl)phosphine]ruthenium(II), 9c. Complex 6c

373 mg, 0.5 mmol) was dissolved in 20 mL of dichloromethane, and

Yield: 439 mg (72%).

1

IR (ν): 3053, 2950, 1729 (CO), 1434, 1293, 1274, 1109, 750. H

(

NMR (300.0 MHz): 2.53 (m, br, 1H), 2.95 (m, br, 1H), 3.10 (m, br,

the solution was stirred for 4 h exposed to the light of a conventional

desk lamp. Elimination of the solvent left a residue, which was puriﬁed

by recrystallization in dichloromethane/hexane, aﬀording the title

product as a brownish solid. Yield: 241 mg (79%).

1

H), 3.46 (m, br, 1H), 3.86 (s, 3H), 4.62 (t, J = 5.7, 1H), 5.20−5.30

(

m, 2H), 6.21 (d, J = 5.7, 1H), 6.48 (d, J = 6.0, 1H), 7.29−7.35 (m,

3

7

8

H), 7.38−7.44 (m, 3H), 7.51−7.56 (m, 2H), 7.71−7.78 (m, 7H),

.78 (td, J = 7.8, 1.2, 1H), 8.05 (d, J = 7.8, 1H), 8.41−8.48 (m, 2H),

.81 (t, J = 7.5, 2H). C{ H} NMR (101 MHz): 29.3 (d, J = 27.7,

IR (ν): 3056, 3019, 2958, 1598, 1492, 1433, 1241, 1154, 833, 818,

1

3

1

PC

768, 698, 511, 484. H NMR (400.1 MHz): −0.16 (s, 3H), −0.15 (s,

2

CH ), 31.1 (d, J = 4.5, CH ), 53.3 (s, CH ), 83.4 (m, br, CH), 87.0

3H), 1.67 (dd, J , J = 20.0, 14.0, 1H), 1.97 (d, J = 13.6, 1H),

2

PC

2

3

PH HH HH

2

(

1

+

m, br, CH), 90.8 (s, CH), 92.5 (s, CH), 97.0 (m, br, CH), 122.7−

2.22 (d, J = 13.2, 1H), 2.38 (dd, J , J = 16.5, 14.0, 1H), 4.97

HH PH HH

3

1

39.2 (C, CH, Ar), 164.7 (s, CO). P{ H} NMR (121 MHz):

(d, J = 6.0, 1H), 5.02 (d, J = 5.6, 1H), 5.70 (t, J = 5.6, 1H), 6.26 (t, J =

6.0, 1H), 6.35 (td, J = 6.4, 2.4, 1H), 6.89 (d, J = 7.0, 2H), 7.05 (tt, J =

7.6, 1.2, 1H), 7.16 (t, J = 7.0, 2H), 7.29−7.33 (m, 5H), 7.55 (tt, J = 8.8,

24.1 (s). Anal.: calcd. for C H Cl O PRu: C 64.17%, H 4.44%;

40 33 2 2

found C 63.70%, H 4.81%.

9

87

DOI: 10.1021/acs.organomet.5b00018

Organometallics 2015, 34, 973−994

Organometallics

Article

1

3

1

(

.2, 1H), 7.61−7.66 (m, 1H), 7.67−7.69 (m, 2H). C{ H} NMR

3.64 (m, 1H, M), 4.12 (m, br, 1H, m), 4.72 (s, br, 1H, m), 4.78 (m, br,

3

13

1

101 MHz): −1.6 (d, J = 2.3, CH ), −1.4 (d, J = 2.2, CH ), 11.5

d, J = 16.6, CH ), 26.8 (d, J = 3.5, CH ), 79.4 (s, CH), 80.2 (s,

1H, M), 6.81−7.92 (m, Ar, 20H, m + M). C{ H} NMR (101 MHz):

PC

3

PC

3

1

3

2

9.3 (m, CH , m), 11.0 (m, CH , M), 31.9 (d, J = 4.3, CH , M),

PC

2

PC

2

3

PC

3

2

CH), 89.6 (d, J = 15.6, CH), 94.8 (s, CH), 101.7 (d, J = 5.6, CH),

32.42 (d, J = 4.1, CH , m), 57.8 (d, J = 11.0, CH, m), 57.9 (d,

J_P_C= 10.8, CH, M), 78.7 (d, J = 0.9, CH, m), 78.9 (d, J = 1.1,

PC PC

CH, M), 124.2−145.0 (C, CH, Ar). P{ H} NMR (121 MHz): +70.6

(br, s). HRMS(ESI): calcd. for C H BNNaOP ([M] + Na),

PC 3 PC

3

1

2

3

1

09.8 (d, J = 3.0, C), 124.1−145.0 (C, CH, Ar). P{ H} NMR (121

31

1

MHz): +50.7 (s). Anal.: calcd. for C H Cl PRuSi: C 56.37%, H

28

29

2

4

.71%; found C 56.56%, H 5.17%.

-Bromo-m-terphenyl, ArBre. A Schlenk ﬂask was charged with

Pd(dba) ] (0.332 g, 0.363 mmol), PPh (0.656 g, 2.90 mmol), and 80

mL of 1,2-dimethoxyethane. The mixture was left stirring for 10 min,

and 1-bromo-2-iodobenzene (1.4 g, 5 mmol) was rapidly added. After

5 min, the mixture had become greenish and a suspension of 3-

biphenylboronic acid (1.0 g, 5 mmol) in 80 mL of aqueous 2 M

Na CO solution was added, and the biphasic mixture was brought to

reﬂux for 12 h. The mixture was cooled down to room temperature

and extracted with dichloromethane (2 × 100 mL). The combined

organic phases were washed with water, dried with anhydrous sodium

sulfate, and ﬁltered. The solvents were removed under vacuum, leaving

a yellow pasty solid, which was puriﬁed by column chromatography

32

33

2

512.2285; found, 512.2293. [α] (c = 1.0, CH Cl ) = +63.5°.

D 2 2

[

(1R,2S)-2-{[(S)-Phenyl(2-(2′-naphthyl)phenyl)phosphanyl]-

methylamino}-1-phenylpropan-1-ol-borane, 19g. The proce-

dure was the same as that used to prepare 19f. Starting from precursor

ArBrg (1.60 g, 5.7 mmol) and oxazaphospholidine-borane 18 (1.00 g,

4.0 mmol), the title product was obtained as a white foam. Yield: 1.50

g (77%).

2

3

1

2

3

1

H NMR (400.1 MHz): 0.52 (d, J = 6.8, 3H), 2.54 (d, ³J_P_H= 7.6,

2

HH

3

3H), 3.95 (m, 1H), 4.79 (d, J = 3.2, 1H), 7.11−7.30 (m, 8H),

HH

7.32−7.55 (m, 7H), 7.60−7.67 (m, 3H), 7.71−7.75 (m, 2H), 7.84 (s,

13

1

3

br, 1H). C{ H} NMR (100.6 MHz): 9.9 (d, J = 6.3, CH ), 31.7

PC

3

2

(d, J = 4.0, CH ), 58.1 (d, J = 10.0, CH), 78.6 (s, CH), 125.6−

PC

3

PC

31

1

(

SiO ﬂash, ﬁrst eluting with pure hexane and then with a 80:20

hexane:dichloromethane). The title product was obtained as a

colorless oil that solidiﬁed upon standing. Yield: 1.3 g (84%).

147.2 (C, CH, Ar). P{ H} NMR (121 MHz): +70.1 (d, br, J ≈ 73).

HRMS(ESI): calcd. for C H NOP ([M] − BH ), 476.2738; found,

2

32

30

3

476.2145. [α] (c = 0.5, CH Cl ) = +10.3°.

D 2 2

1

H NMR (400.1 MHz): 7.23 (m, 1H), 7.35−7.54 (m, 7H), 7.62−

(R)-Methoxyphenyl(2-m-terphenylyl)phosphine-borane,

20e. Compound 19e (0.550 g, 1.16 mmol) was dissolved in 80 mL of

1

3

1

7

1

.72 (m, 5H). C{ H} NMR (101 MHz): 122.6 (C), 126.3 (CH),

27.2 (2CH), 127.38 (CH), 127.41 (CH), 128.2 (CH), 128.3 (CH),

28.4 (CH), 128.77 (2CH), 128.81 (CH), 131.3 (CH), 133.2 (CH),

40.9 (2C), 141.5 (C), 142.4 (C). MS(EI): 309.9 ([M] + H), 307.7

freshly distilled methanol, concentrated H SO (0.13 mL, 0.228 g, 2.32

2 4

mmol) was carefully added, and the solution was stirred overnight.

The solvent was removed in vacuo, and the crude was puriﬁed by a

(

[M] − H).

column chromatography (ﬂash SiO , 95:5 hexane/ethyl acetate). The

2

(

1R,2S)-2-{[(S)-Phenyl(2-m-terphenylyl)phosphanyl]methyl-

title product was obtained as a bright white foam. Yield: 330 mg

(74%).

amino}-1-phenylpropan-1-ol-borane, 19e. Precursor ArBre (2.77

g, 8.96 mmol) was dissolved in 180 mL of diethyl ether in a Schlenk

ﬂask. The solution was cooled to −78 °C, and then 1.6 M n-BuLi

solution in hexanes (4.3 mL, 6.9 mmol) was added by syringe. The

resulting orange solution was stirred for 2 h, maintaining the low

temperature. At the same time, the oxazaphospholidine-borane 18

¹H NMR (400.1 MHz): 3.62 (d, ³J_P_H= 12.0, 3H), 6.96 (d, br, J =

7.6, 1H), 7.09 (t, J = 1.6, 1H), 7.13−7.60 (m, 15H), 8.13 (ddd, J =

12.8, 7.2, 2.0, 1H). ¹³C{ H} NMR (101 MHz): 53.7 (d, J = 2.3,

1

2

PC

31

1

CH ), 125.9−146.5 (C, CH, Ar). P{ H} NMR (121 MHz): +109.1

3

(d, br, J ≈ 72). HRMS(ESI): calcd. for C H BNaOP ([M] + Na),

25

24

(

1.71 g, 6.89 mmol) was dissolved in 30 mL of THF, and the solution

405.1550; found, 405.1550. [α] (c = 1, CH Cl ): −13.9°.

D

2

was cooled down to −78 °C. After 2 h, the content of the ﬁrst ﬂask

was slowly transferred to the second Schlenk ﬂask via cannula, and the

resulting mixture was stirred overnight. Around 10 mL of water was

added to the orange solution, and THF was evaporated. The orange-

red residue was extracted with dichloromethane (2 × 60 mL), and the

combined organic phases were washed with water and dried with

anhydrous sodium sulfate. The suspension was ﬁltered, and the

solvents were evaporated to dryness, leaving a pasty solid, which was

(R)-Methoxy(2-(1′-(naphthyl)phenyl))phenylphosphine-bor-

ane, 20f. Precursor 19f (1.94 g, 3.97 mmol) was dissolved in 100 mL

of freshly distilled methanol, concentrated H

7.95 mmol) was carefully added, and the solution was stirred

overnight. The day after, one more equivalent of H SO was added,

SO (0.43 mL, 0.779 g,

2

4

2

4

and the solution was again left stirring overnight. The workup

procedure was exactly the same as that followed to prepare 14e. The

title product was obtained as a bright white foam. Yield: 785 mg

(55%).

puriﬁed by column chromatography (ﬂash SiO , from 95:5 to 80:20 of

2

¹H NMR (400.1 MHz): 3.38 (d, ³JPH = 12.0, 3H), 3.49 (d, ³JPH

=

hexane/ethyl acetate). The title product was obtained as a white foam.

Yield: 3.0 g (85%).

12.0, 3H), 6.88−6.94 (m, 3H), 6.99−7.20 (m, 10H), 7.23−7.62 (m,

1

H NMR (400.1 MHz): 0.68 (d, J = 6.8, 3H), 2.57 (d, ³J = 7.6,

2

13H), 7.68−7.79 (m, 4H), 7.91 (m, 1H), 8.16−8.23 (m, 2H).

HH

PH

1

3

1

13

1

2

3

H), 3.99 (m, 1H), 4.85 (br, s, 1H), 7.10−7.73 (m, Ar, 23H). C{ H}

NMR (101 MHz): 10.0 (d, J = 6.3, CH ), 31.65 (d, J = 4.0,

CH ), 58.1 (d, J = 10.3, CH), 78.6 (s, br, CH), 125.6−147.0 (C,

CH, Ar). P{ H} NMR (121 MHz): +70.1 (br, s). HRMS(ESI):

calcd. for C H BNOP ([M] − H), 514.2465; found, 514.2471. [α]

C{ H} NMR (101 MHz): 53.58 (d, J = 2.3, CH ), 53.66 (d, J

PC

31

3

PC

3

2

1

PC

3

PC

= 2.1, CH ), 124.1−144.6 (C, CH, Ar). P{ H} NMR (162 MHz):

3

2

3

PC

+108.6 (d, br, J ≈ 89). HRMS(ESI): calcd. for C H BOP ([M] −

23 21

3

1

H), 355.1417; found, 355.1426. [α] (c = 1, CH Cl ): −41.9°.

D

2

34

D

(R)-Methoxy(2-(2′-(naphthyl)phenyl))phenylphosphine-bor-

ane, 20g. The procedure was the same as that used to prepare 20f but

starting from precursor 19g (75 mg, 0.15 mmol). The desired

phosphinite-borane was obtained as a colorless oil. Yield: 60 mg

(92%).

(c = 1.0, CH Cl ) = +65.7°.

2 2

(

1R,2S)-2-{[(S)-(2-(1′-Naphthyl)phenyl)phenylphosphanyl]-

methylamino}-1-phenylpropan-1-ol-borane, 19f. Precursor

ArBrf (1.33 g, 4.69 mmol) was dissolved in 150 mL of diethyl ether

in a Schlenk ﬂask. The solution was cooled to −78 °C, and then 1.6 M

n-BuLi solution in hexanes (2.1 mL, 3.35 mmol) was added by syringe.

The resulting orange solution was stirred for 2 h at −78 °C, warmed

up to −25 °C, left stirring at this temperature for 30 min, and recooled

to −78 °C. In parallel, precursor 18 (0.830 g, 3.35 mmol) was

dissolved in 20 mL of THF and the solution was cooled down to −78

¹H NMR (400.1 MHz): 3.54 (d, ³J_P_H= 12.0, 3H), 7.05−7.10 (m,

3H), 7.20−7.31 (m, 5H), 7.42−7.50 (m, 2H), 7.51−7.60 (m, 4H),

13

1

7.78 (m, 1H), 8.11 (ddd, J = 12.0, 7.2, 2.0, 1H). C{ H} NMR (101

2

31

1

MHz): 53.6 (d, J = 2.5, CH ), 126.0−146.5 (C, CH, Ar). P{ H}

PC

3

NMR (162 MHz): +109.0 (d, br, J ≈ 88). HRMS(ESI): calcd. for

C H OP ([M] − BH ), 343.1246; found, 343.1250. [α] (c = 1.0,

23

20

3

D

°

C. The content of the ﬁrst ﬂask was slowly transferred to the second

CH Cl ) = −8.2°.

2

Schlenk via cannula, and the resulting mixture was stirred overnight.

The workup procedure was exactly the same as that followed to

prepare 19e. Finally, compound 19f was obtained as a white foam.

Yield: 1.6 g (97%).

(S)-Isopropylphenyl(2-m-terphenylyl)phosphine-borane,

23e. Phosphinite-borane 20e (0.500 g, 1.31 mmol) was dissolved in

30 mL of diethyl ether, and the solution was cooled to −30 °C. A 0.7

i

M PrLi solution (4.67 mL, 3.27 mmol) was added by syringe, and the

1

2

3

H NMR (400.1 MHz): 0.13 (d, J = 7.2, 3H, M), 1.15 (d, J

=

mixture was stirred for 3 h before slowly warming it up to room

temperature. The solution was cooled again to −30 °C, an extra

HH

3

6

.8, 3H, m), 2.36 (d, J = 7.2, 3H, M), 2.73 (d, J = 7.2, 3H, m),

PH

9

88

DOI: 10.1021/acs.organomet.5b00018

Organometallics 2015, 34, 973−994

Organometallics

Article

i

MHz): 56.6 (d, ²J_P_C= 21.7, CH ), 126.0−146.0 (C, CH, Ar). P{ H}

31

1

equivalent of PrLi (1.87 mL, 1.31 mmol) was added, and the mixture

3

was stirred for 2 h before warming it up slowly to room temperature.

Water was added, the mixture was extracted with diethyl ether (3 × 10

mL), and the combined organic phases are washed with 20 mL of

water and dried with anhydrous sodium sulfate. After ﬁltration, the

solvent was removed in vacuo and the crude product was puriﬁed by

NMR (162 MHz): +109.1 (s).

(S)-Isopropylphenyl(2-m-terphenylyl)phosphine, 25e. The

procedure was the same as that used to prepare 2a. Starting from

phosphine-borane 23e (130 mg, 0.33 mmol), the title product was

obtained as a white pasty solid. Yield: 90 mg (72%).

1

3

column chromatography (ﬂash SiO , 95:5 hexane/ethyl acetate).

Yield: 279 mg (54%).

H NMR (400.1 MHz): 0.94 (dd, JPH, JHH = 15.2, 6.8, 3H), 1.09

2

3

(dd, JPH, JHH = 15.6, 6.8, 3H), 2.41 (septet, JHH = 6.8, 1H), 7.18−

1

3

H NMR (400.1 MHz): 1.09−1.17 (m, 6H), 2.51 (septet, J

=

7.27 (m, 5H), 7.30−7.48 (m, 11H), 7.55 (ddd, J = 7.6, 3.2, 1.2, 1H),

HH

1

3

1

2

7

.2, 1H), 6.93 (s, br, 2H), 7.09 (s, br, 3H), 7.19−7.26 (m, 4H), 7.34

7.73 (m, 1H). C{ H} NMR (101 MHz): 19.4 (d, JPC = 19.7, CH

),

3

2

1

(

m, 1H), 7.38−7.42 (m, 4H), 7.49−7.52 (m, 3H), 8.17 (m, 1H).

20.1 (d, JPC = 20.1, CH

3

), 25.5 (d, JPC = 9.8, CH), 125.6−148.9 (C,

CH, Ar). ³¹P{ H} NMR (121 MHz): −9.7 (s).

1

3

1

2

C{ H} NMR (101 MHz): 17.1 (d, J = 3.0, CH ), 17.7 (s, CH ),

PC

3

1

31

1

(S)-Isopropyl(2-(1′-(naphthyl)phenyl)phenylphosphine, 25f.

The procedure was the same as that used to prepare 2a. Starting from

phosphine-borane 23f (680 mg, 1.84 mmol), the title product was

isolated as a white pasty solid. Yield: 570 mg (58%).

H NMR (400.1 MHz): 0.83 (dd, J , J = 15.6, 6.8, 3H, M),

.88 (dd, J , J = 15.6, 6.8, 3H, m), 1.03 (dd, J , J = 15.6, 6.8,

2

2.6 ( J , J = 36.8, CH), 126.0−147.0 (C, CH, Ar). P{ H} NMR

PC

(

121 MHz): +23.6 (d, br, J ≈ 37). HRMS(ESI): calcd. for C H BNP

27

32

(

[M] + NH ), 412.2359; found, 412.2357. [α] (c = 1, CH Cl ):

4 D 2 2

−

14.5°.

1

3

(

S)-Isopropyl(2-(1′-(naphthyl)phenyl))phenylphosphine-

PH

HH

3

0

3

borane, 23f. Phosphinite-borane 20f (0.750 g, 2.1 mmol) was

PH HH PH HH

3

H, M), 1.09 (dd, J , J = 15.6, 6.8, 3H, m), 2.42 (septet, J =

HH

6.8, 1H), 2.43 (septet, J = 6.8, 1H), 6.79 (dd, J = 7.2, 1.2, 1H),

dissolved in 40 mL of diethyl ether, and the solution was cooled down

to −30 °C. A 0.7 M PrLi solution (6.0 mL, 4.21 mmol) was added by

syringe, the mixture was stirred for 6 h at low temperature, and then it

was allowed to slowly reach room temperature. The workup procedure

was exactly the same as that followed to prepare 17e. Yield: 680 mg

PH

HH

3

i

HH

6

1

2

.96−7.09 (m, 6H), 7.22−7.60 (m, 20H), 7.69 (ddd, J = 7.6, 2.8, 1.2,

13 1 2

H), 7.79−7.90 (m, 4H). C{ H} NMR (101 MHz): 19.2 (d, J

=

PC

2

0.7, CH , M), 19.46 (d, J = 20.0, CH , m), 19.8 (d, J = 20.6,

3

PC

3

PC

2

1

CH , M), 19.9 (d, J = 19.5, CH , m), 25.4 (d, J = 9.3, CH), 24.7

(d, J = 9.3, CH), 124.4−147.2 (C, CH, Ar). P{ H} NMR (121

(

88%).

3

PC

3

PC

31

1

3

H NMR (400.1 MHz): 0.97 (dd, J , J = 16.0, 7.6, 3H, m),

PC

PH

HH

3

MHz): −12.0 (s, m), −11.7 (s, M).

0

3

6

.99 (dd, J , J = 16.3, 6.3, 3H, m), 1.10 (dd, J , J = 16.8, 7.2,

PH HH PH HH

3

(S)-Isopropyl(2-(2′-(naphthyl)phenyl)phenylphosphine, 25g.

The procedure was the same as that used to prepare 2a. Starting from

phosphine-borane 23g (175 mg, 0.48 mmol), the title product was

isolated as a white pasty solid. Yield: 120 mg (71%).

H, M), 1.18 (dd, J , J = 16.8, 7.2, 3H, M), 2.08 (septet, J =

HH

PH

HH

3

.8, 1H, m), 2.76 (septet, J = 7.2, 1H, M), 6.58−8.40 (m, Ar, 32

HH

3

1

H). P{ H} NMR (162 MHz): +28.1 (s, br). HRMS(ESI): calcd. for

C H BP ([M] − H), 367.1781; found, 367.1796. [α] (c = 1,

25

D

1

3

H NMR (400.1 MHz): 0.91 (dd, J , J = 15.6, 6.8, 3H), 1.06

PH

HH

CH Cl ): −95.8°.

2

3

(

dd, J , J = 16.0, 7.2, 3H), 2.42 (septet, J = 6.8, 1H), 7.24−

PH

HH

(

S)-Isopropyl(2-(2′-(naphthyl)phenyl))phenylphosphine-

borane, 23g. The procedure was the same as that used to prepare

3f. Starting from phosphinite-borane 20g (250 mg, 0.70 mmol), the

title product was obtained as a white pasty solid. Yield: 205 mg (80%).

7

(

.29 (m, 3H), 7.32−7.39 (m, 4H), 7.40−7.49 (m, 5H), 7.66 (m, 1H),

13 1

.74 (m, 1H), 7.79 (d, J = 9.2, 1H), 7.85 (m, 1H). C{ H} NMR

2

101 MHz): 19.4 (d, J = 20.2, CH ), 19.9 (d, J = 19.7, CH ),

PC 3 PC 3

1

31

1

3

25.6 (d, J = 9.4, CH), 125.8−149.0 (C, CH, Ar). P{ H} NMR

PC

H NMR (400.1 MHz): 1.08 (dd, J , J = 15.6, 6.8, 3H), 1.09

PH

HH

3

(162 MHz): −10.5 (s).

(

dd, J , J = 16.8, 7.2, 3H), 2.41 (septet, J = 7.2, 1H), 7.05 (td,

PH HH HH

6

Dichloro(η -methyl benzoate)[(S)-(2-biphenylyl)methoxy-

J = 10.0, 2.0, 3H), 7.11 (d, J = 1.6, 1H), 7.13 (d, J = 2.0, 1H), 7.19−

phenylphosphine]ruthenium(II), 10c. The procedure was the

same as that used to prepare 6a. Starting from phosphinite (R)-(2-

biphenylyl)methoxyphenylphosphine (292 mg, 1 mmol), the title

product was obtained as a brownish solid. Yield: 402 mg (84%).

IR (ν): 3054, 2948, 2840, 1728 (CO), 1433, 1294, 1276, 1109,

7

1

.24 (m, 3H), 7.43−7.54 (m, 6H), 7.63 (m, br, 1H), 7.82 (d, J = 8.8,

1

3

1

2

H), 8.20 (m, 1H). C{ H} NMR (101 MHz): 17.2 (d, J = 2.9,

PC

2

1

CH ), 17.7 (d, J = 1.0, CH ), 22.2 (d, J = 33.7, CH), 126.2−

3

PC

3

PC

3

1

47.0 (C, CH, Ar). P{ H} NMR (162 MHz): +28.8 (d, br, J ≈ 75).

HRMS(ESI): calcd. for C H P ([M] − H), 355.1610; found,

1

3

25

24

1

030, 769, 756, 694, 525, 503. H NMR (400.1 MHz): 3.54 (d, J

=

PH

355.1608.

2.4, 3H), 3.92 (s, 3H), 4.92 (t, J = 6.0, 1H), 4.97 (t, J = 5.6, 1H), 5.46

m, 1H), 6.42 (t, J = 5.5, 1H), 6.44 (t, J = 5.5, 1H), 6.76 (s, br, 2H),

.01−7.08 (m, 3H), 7.14−7.23 (m, 3H), 7.24−7.31 (m, 1H), 7.37−

.48 (m, 4H), 8.68 (ddd, J = 14.8, 7.2, 1.6, 1H). P{ H} NMR (121

(

R)-Methoxyphenyl(2-m-terphenylyl)phosphine, 21e. The

(

procedure was the same as that used to prepare 2a. Starting from

phosphinite-borane 20e (500 mg, 1.3 mmol), the title product was

obtained as a white pasty solid. Yield: 400 mg (83%).

H NMR (400.1 MHz): 3.60 (d, J = 14.0, 3H), 7.23−7.73 (m,

7H), 7.86 (m, 1H). C{ H} NMR (101 MHz): 56.6 (d, J = 21.9,

7

31 1

MHz): +112.7 (s). Anal.: calcd. for C H Cl O PRu: C 54.01%, H

1

3

27 25

2

3

PH

4

.20%; found C 52.32%, H 4.46%.

1

3

1

2

1

6

PC

Dichloro(η -p-cymene)[(S)-(2-biphenylyl)methoxyphenyl-

3

1

CH ), 122.6−145.7 (C, CH, Ar). P{ H} NMR (121 MHz): +110.1

3

phosphine]ruthenium(II), 10c′. The procedure was the same as

that used to prepare 4a. Starting from phosphinite (R)-(2-biphenylyl)-

methoxyphenylphosphine (292 mg, 1 mmol), the title product was

obtained as an orange solid. Yield: 308 mg (63%).

(

s).

(

R)-Methoxy(2-(1′-(naphthyl)phenyl)phenylphosphine, 21f.

The procedure was the same as that used to prepare 21e. Starting

from phosphinite-borane 20f (300 mg, 0.84 mmol), the title product

was obtained as a white pasty solid. Yield: 172 mg (59%).

IR (ν): 3058, 2959, 2868, 1465, 1430, 1385, 1108, 1081, 1027, 756,

06, 525, 500. H NMR (400.1 MHz): 0.97 (d, J = 6.8, 3H), 1.04

(d, J = 7.2, 3H), 1.84 (s, 3H), 2.64 (septet, J = 6.8, 1H), 3.51 (d,

1

3

7

HH

1

3

H NMR (400.1 MHz): 3.34 (d, J = 14.0, 3H), 3.54 (d, J

=

PH

HH HH

3

1

7

4.0, 3H), 6.85−6.88 (m, 4H), 6.90−7.02 (m, 3H), 7.22−7.63 (m,

J_P_H= 12.0, 3H), 4.95 (d, J = 6.0, 1H), 5.12−5.13 (m, 2H), 5.18 (d, J =

8H), 7.73−7.80 (m, 1H), 7.80−7.83 (m, 2H), 7.86 (d, J = 8.8, 2H),

6

.8, 1H), 6.78 (s, br, 2H), 7.00−7.05 (m, 3H), 7.11−7.20 (m, 3H),

1

3

1

2

.90−7.94 (m, 2H). C{ H} NMR (101 MHz): 56.47 (d, J = 22.1,

13 1

PC

7.23 (td, J = 7.2, 1.6, 1H), 7.37−7.47 (m, 4H), 8.66 (m, 1H). C{ H}

3

1

CH ), 56.64 (d, J = 22.6, CH ), 124.6−144.0 (C, CH, Ar). P{ H}

3

NMR (101 MHz): 17.4 (s, CH ), 21.5 (s, CH ), 21.7 (s, CH ), 29.9

3

2

NMR (121 MHz): +108.4 (s), +108.5 (s).

(

s, CH), 54.4 (d, J = 3.3, CH ), 86.8 (d, J = 5.8, CH), 87.0 (d, J =

.6, CH), 91.5 (d, J = 4.3, CH), 91.8 (d, J = 4.5, CH), 96.3 (s, C),

11.2 (d, J = 1.4, C), 126.1−145.7 (C, CH, Ar). P{ H} NMR (121

MHz): +114.6 (s). Anal.: calcd. for C H Cl OPRu: C 58.20%, H

PC 3

(

R)-Methoxy(2-(2′-(naphthyl)phenyl)phenylphosphine, 21g.

6

1

31

1

The procedure was the same as that used to prepare 2a. Starting from

phosphinite-borane 20g (120 mg, 0.34 mmol), the title product was

isolated as a colorless oil. Yield: 70 mg (61%).

29

31

2

5.22%; found C 57.69%, H 5.77%.

1

3

6

H NMR (400.1 MHz): 3.52 (d, J = 14.0, 3H), 7.22−7.33 (m,

Dichloro(η -methyl benzoate)[(R)-(2-biphenylyl)methyl-

phenylphosphine]ruthenium(II), 11c. The procedure was the

same as that used to prepare 6a. Starting from (S)-(2-biphenylyl)-

PH

5

(

H), 7.37 (d, J = 9.6, 2H), 7.42−7.52 (m, 4H), 7.55 (s, br, 1H), 7.69

m, 1H), 7.80 (d, J = 8.0, 2H), 7.86 (m, 1H). ¹C{ H} NMR (101

3 1

9

89

DOI: 10.1021/acs.organomet.5b00018

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Organometallics

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3

1

methylphenylphosphine (276 mg, 1 mmol), the title product was

isolated as a reddish solid. Yield: 350 mg (73%).

P{ H} NMR (162 MHz): +110.1 (s). Anal.: calcd. for C H -

33 29

Cl O PRu: C 58.59%, H 4.32%; found C 58.67%, H 4.55%.

2

3

6

IR (ν): 3053, 2951, 1727 (CO), 1434, 1293, 1275, 1109, 896,

Dichloro(η -methyl benzoate)[(R)-methylphenyl(2-p-

terphenylyl)phosphine]ruthenium(II), 27d. The procedure was

the same as that used to prepare 6a. Starting from phosphine 24d (330

mg, 0.94 mmol), the title product was isolated as an orange solid.

Yield: 244 mg (47%).

1

2

7

3

60, 731, 703, 506, 481. H NMR (400.1 MHz): 1.64 (d, J = 11.6,

PH

H), 3.87 (s, 3H), 5.33 (t, J = 5.6, 1H), 5.36 (t, J = 5.6, 1H), 5.62 (tdt,

J = 4.8, 2.4, 0.8, 1H), 6.31 (d, J = 6.0, 1H), 6.45 (d, J = 6.0, 1H), 6.83

(

d, J = 7.2, 2H), 7.09 (t, J = 7.6, 2H), 7.16−7.28 (m, 4H), 7.29−7.34

31 1

m, 3H), 7.51−7.55 (m, 2H), 8.33−8.39 (m, 1H). P{ H} NMR

121 MHz): +22.4 (s). HRMS(ESI): calcd. for C H ClO PRu (M −

IR (ν): 3082, 2952, 1728 (CO), 1432, 1269, 1110, 895, 769, 696,

1

2

502. H NMR (400.1 MHz): 1.75 (d, JPH = 11.6, 3H), 3.87 (s, 3H),

5.32 (t, J = 6.0, 1H), 5.38 (t, J = 6.0, 1H), 5.63 (m, 1H), 6.32 (d, J =

6

1

NMR (162 MHz): +22.2 (s). HRMS(ESI): calcd. for C33

Cl NO PRu ([M] + NH ), 678.0663; found, 678.0655. UV−vis

(λmax (ε)): 360 (2400), 490 (350).

Dichloro(η -methyl benzoate)[(R)-isopropylphenyl(2-p-

terphenylyl)phosphine]ruthenium(II), 28d. The procedure was

the same as that used to prepare 6a. Starting from phosphine 25d (170

mg, 0.45 mmol), the title product was isolated as an orange solid.

Yield: 205 mg (80%).

27

25

2

Cl), 549.0318; found, 549.0324. UV−vis (λ (ε)): 360 (2400), 490

(

max

.4, 1H), 6.47 (d, J = 5.6, 1H), 6.90 (d, br, J = 7.6, 2H), 7.21−7.38 (m,

0H), 7.40−7.46 (m, 2H), 7.50−7.58 (m, 3H), 8.40 (m, 1H). P{ H}

330).

Dichloro(η -p-cymene)[(R)-(2-biphenylyl)methylphenyl-

31 1

6

phosphine]ruthenium(II), 11c′. The procedure was the same as

that used to prepare 4a. Starting from (S)-(2-biphenylyl)methyl-

phenylphosphine (276 mg, 1 mmol), the title product was obtained as

an orange solid. Yield: 324 mg (68%).

H -

33

2

4

6

IR (ν): 3051, 2962, 2927, 2870, 1585, 1465, 1435, 1386, 1271,

1

105, 1082, 1030, 894, 776, 763, 730, 697, 503. H NMR (400.1

3

2

MHz): 0.69 (d, J = 6.8, 3H), 1.04 (d, J = 6.8, 3H), 1.66 (d, J

11.2, 3H), 2.03 (s, 3H), 2.66 (septet, J = 6.8, 1H), 4.90 (d, J =

HH

PH

3

=

IR (ν): 3063, 2951, 1728 (CO), 1433, 1275, 1110, 765, 698, 526.

6

1

8

.0, 1H), 5.33 (d, J = 6.0, 1H), 5.40 (d, J = 6.8, 1H), 5.43 (d, J = 6.8,

H), 6.83 (d, J = 7.0, 2H), 7.03 (t, J = 7.6, 2H), 7.12 (tt, J = 7.2, 1.6,

H), 7.16−7.25 (m, 4H), 7.28−7.34 (m, 2H), 7.43−7.51 (m, 2H),

1

3

H NMR (400.1 MHz): 0.91 (dd, J , J = 18.0, 7.2, 3H), 1.11 (dd,

PH

HH

3

J , J = 15.2, 6.8, 3H), 2.87 (m, 1H), 3.98 (s, 3H), 5.08 (t, J = 6.0,

PH

HH

1

3

1

(

H), 5.26 (t, J = 6.0, 1H), 5.33 (m, br, 1H), 6.43 (d, J = 6.0, 1H), 6.53

d, J = 5.6, 1H), 7.17 (t, br, J = 7.0, 3H), 7.29 (t, br, J = 7.4, 2H), 7.38

d, br, J = 7.6, 4H), 7.44−7.49 (m, 4H), 7.59 (d, br, J = 6.8, 2H), 7.65

.37−8.43 (m, 1H). C{ H} NMR (101 MHz): 13.0 (d, J = 33.9,

PC

CH ), 17.3 (s, CH ), 20.3 (s, CH ), 22.4 (s, CH ), 30.0 (s, CH), 85.2

3

2

(

d, J = 4.5, CH), 87.3 (d, J = 6.9, CH), 87.4 (d, J = 3.1, CH),

PC PC PC

31

1

2

(t, br, J = 8.4, 2H), 8.14 (dd, J = 12.8, 8.0, 1H). P{ H} NMR (162

MHz): +33.5 (s). HRMS(ESI): calcd. for C H ClO PRu ([M] −

Cl), 653.0944; found, 653.0968.

Dichloro(η -methyl benzoate)[(S)-methoxyphenyl(2-m-

terphenylyl)phosphine]ruthenium(II), 26e. The procedure was

the same as that used to prepare 6a. Starting from phosphinite 21e

9

1.9 (d, J = 5.6, CH), 94.0 (s, C), 107.7 (s, C), 126.5−146.1 (C,

PC

31 1

CH, Ar). P{ H} NMR (121 MHz): +22.2 (s). Anal.: calcd. for

C H Cl PRu: C 59.80%, H 5.36%; found C 59.59%, H 5.90%. UV−

vis (λ (ε)): 368 (1700), 490 (440).

35 33

2

29

31

2

6

max

6

Dichloro(η -methyl benzoate)[(R)-(2-biphenylyl)isopropyl-

phenylphosphine]ruthenium(II), 12c. The procedure was the

same as that used to prepare 6a. Starting from (S)-(2-biphenylyl)-

isopropylphenylphosphine (304 mg, 1 mmol), the title product was

isolated as a reddish solid. Yield: 407 mg (65%).

(

200 mg, 0.54 mmol), the title product was isolated as an orange solid.

Yield: 250 mg (68%).

1

IR (ν): 3055, 1729 (CO), 1434, 1294, 1276, 1109, 760, 535. H

3

NMR (400.1 MHz): 3.63 (d, J = 12.4, 3H), 3.94 (s, 3H), 4.87 (t, J

PH

IR (ν): 3053, 2951, 2926, 2868, 1729 (CO), 1465, 1433, 1293,

275, 1109, 756, 702, 523, 495. H NMR (400.1 MHz): 0.85 (dd, J ,

PH

1

3

= 5.6, 1H), 4.94 (t, J = 5.6, 1H), 5.44 (td, J = 5.2, 3.2, 1H), 6.425 (d, J

= 6.4, 1H), 6.441 (d, J = 6.4, 1H), 7.10−7.14 (m, 5H), 7.34−7.48 (m,

1

3

^JHH = 18.4, 6.8, 3H), 1.01 (dd, J , J = 14.9, 7.2, 3H), 2.64 (m,

PH

HH

31

1

2H), 8.76 (ddd, J = 14.4, 7.2, 1.2, 1H). P{ H} NMR (162 MHz):

112.5 (s). Anal.: calcd. for C H Cl O PRu: C 58.59%, H 4.32%;

1

7

H), 3.96 (s, 3H), 5.16 (t, J = 6.0, 1H), 5.20 (t, J = 5.6, 1H), 5.36 (m,

H), 6.43 (d, J = 6.0, 1H), 6.50 (d, J = 6.0, 1H), 7.14−7.25 (m, 8H),

.31 (m, 1H), 7.40 (tt, J = 8.0, 1.6, 1H), 7.47 (tt, J = 7.2, 1.6, 1H),

+

33 29 2 3

found C 57.78%, H 4.70%.

6

Dichloro(η -methyl benzoate)[(R)-isopropylphenyl(2-m-

terphenylyl)phosphine]ruthenium(II), 28e. The procedure was

the same as that used to prepare 6a. Starting from phosphine 25e (227

mg, 0.60 mmol), the title product was isolated as an orange solid.

Yield: 230 mg (54%).

3

1

.62−7.78 (m, 2H), 8.02 (dd, J = 12.4, 7.6, 1H). P{ H} NMR (121

MHz): +34.8 (s). Anal.: calcd. for C H Cl O PRu: C 56.87%, H

29

2

4

.77%; found C 55.27%, H 5.01%.

Dichloro(η -methyl benzoate)[(R)-(2-biphenylyl)ferrocenyl-

6

phenylphosphine]ruthenium(II), 13c. The procedure was the

same as that used to prepare 6a. Starting from (S)-(2-biphenylyl)-

ferrocenylphenylphosphine (300 mg, 0.67 mmol), the title product

was isolated as a reddish solid. Yield: 334 mg (89%).

1

IR (ν): 3054, 1729 (CO), 1434, 1276, 1110, 759, 701, 526. H

3

NMR (400.1 MHz): 0.94 (dd, J , J = 17.6, 6.8, 3H), 1.14 (dd,

PH

HH

3

J , J = 15.6, 7.2, 3H), 2.88 (s, br, 1H), 3.97 (s, 3H), 5.02 (m, br,

PH

HH

1

(

9

(

H), 5.24 (t, J = 5.6, 1H), 5.30 (m, br, 1H), 6.43 (d, J = 6.0, 1H), 6.50

d, J = 6.0, 1H), 7.06−7.19 (m, 5H), 7.23 (m, 1H), 7.32−7.51 (m,

H), 7.61 (t, br, J = 9.2, 2H), 8.22 (t, br, J = 10.0, 1H). P{ H} NMR

IR (ν): 3055, 2951, 1731 (CO), 1434, 1276, 1108, 753, 700, 485.

1

H NMR (400.1 MHz): 3.70 (s, 5H), 3.89 (s, 3H), 4.17 (s, 1H), 4.40

31 1

(

s, 1H), 4.59 (s, 1H), 5.15 (t, J = 5.6, 1H), 5.22 (s, br, 1H), 5.36 (s, br,

121 MHz): +33.4 (s). Anal.: calcd. for C H Cl O PRu: C 61.05%,

35 33 2 2

1

7

2

H), 6.17 (d, J = 5.6, 1H), 6.50 (d, J = 6.0, 1H), 6.96 (t, J = 7.2, 1H),

.02 (t, J = 7.2, 2H), 7.08 (t, J = 7.2, 2H), 7.17 (t, J = 7.2, 1H), 7.22−

.30 (m, 4H), 7.38 (t, J = 7.2, 1H), 7.46 (t, J = 7.6, 1H), 7.73 (s, br,

H 4.83%; found C 59.61%, H 5.10%.

6

Dichloro(η -methyl benzoate)[(S)-methoxy(2-(1′-naphthyl)-

phenyl)phenylphosphine]ruthenium(II), 26f. The procedure

was the same as that used to prepare 6a. Starting from phosphinite

21f (172 mg, 0.50 mmol), the title product was isolated as an orange

solid. Yield: 180 mg (55%).

3

1

H). P{ H} NMR (162 MHz): +18.7 (s). HRMS(ESI): calcd. for

C H ClFeO PRu (M − Cl), 719.0137; found, 719.0143. UV−vis

36

31

2

(

λ

(ε)): 368 (2500), 460 (1150).

Dichloro(η -methyl benzoate)[(S)-methoxyphenyl(2-p-

max

6

IR (ν): 3054, 2948, 2840, 1729 (CO), 1434, 1294, 1276, 1109,

030, 768, 693, 533. H NMR (400.1 MHz): 3.06 (d, J = 12.4, 3H,

PH

terphenylyl)phosphine]ruthenium(II), 26d. The procedure was

the same as that used to prepare 6a. Starting from phosphinite 21d

1

3

1

3

m), 3.66 (d, J = 12.0, 3H, M), 3.90 (s, 3H, m), 3.95 (s, 3H, M),

4

m), 5.04 (t, J = 5.6, 1H, m), 5.35 (m, br, 2H, m + M), 6.34 (d, J = 7.2,

2

8.98 (m, 16H, M + m). P{ H} NMR (162 MHz): +109.1 (s, M),

+113.4 (s, m). Anal.: calcd. for C H Cl O PRu: C 57.24%, H 4.18%;

found C 56.27%, H 4.74%.

PH

(

200 mg, 0.54 mmol), the title product was isolated as an orange solid.

.67 (t, J = 5.6, 1H, M), 4.85 (t, J = 5.6, 1H, M), 4.88 (t, J = 5.6, 1H,

Yield: 265 mg (85%).

−1

IR (ν, cm ): 3054, 2949, 2840, 1726 (CO), 1433, 1292, 1275,

=

PH

2.4, 3H), 3.94 (s, 3H), 4.86 (t, J = 5.6, 1H), 4.96 (t, J = 5.6, 1H), 5.46

H, m + M), 6.38 (d, J = 6.0, 1H, M), 6.42 (d, J = 6.4, 1H, M), 6.61−

31 1

1

3

1

109, 1024, 766, 535, 516. H NMR (400.1 MHz): 3.63 (d, J

31

27

2

3

(

m, 1H), 6.43 (d, J = 5.8, 1H), 6.45 (d, J = 5.8, 1H), 6.80 (s, br, 2H),

6

7

.09−7.12 (m, 1H), 7.14−7.19 (m, 2H), 7.25−7.30 (m, 3H), 7.36−

.50 (m, 7H), 7.56−7.59 (m, 2H), 8.79 (ddd, J = 14.8, 7.6, 2.0, 1H).

Dichloro(η -methyl benzoate)[(R)-isopropyl(2-(1′-naphthyl)-

phenyl)phenylphosphine]ruthenium(II), 28f. The procedure was

9

90

DOI: 10.1021/acs.organomet.5b00018

Organometallics 2015, 34, 973−994

Organometallics

Article

the same as that used to prepare 6a. Starting from phosphine 25f (570

mg, 1.61 mmol), the title product was isolated as an orange solid.

Yield: 710 mg (65%).

used to prepare 9c. Starting from complex 12c (313 mg, 0.5 mmol),

the desired product was obtained as a brown solid. Yield: 211 mg

(86%).

IR (ν): 3054, 2951, 1729 (CO), 1423, 1294, 1276, 1111, 769,

IR (ν): 3056, 2976, 2958, 2923, 2860, 1434, 1274, 1245, 1110, 774,

1

3

1

3

5

1

3

22. H NMR (400.1 MHz): 0.86 (m, 3H, M), 1.05 (dd, J , J

=

749, 694, 525, 514. H NMR (400.1 MHz): 1.13 (dd, J , J = 19.6,

PH

HH

PH HH

3

6.4, 6.8, 3H, M), 1.13 (dd, J , J = 14.8, 7.2, 3H, m), 1.25 (m,

6.8, 3H), 1.29 (dd, J , J = 13.2, 7.2, 3H), 3.24 (septet, J = 7.2,

PH HH HH

PH

HH

H, m), 2.93 (s, br, 1H, M), 3.24 (s, br, 1H, m), 3.99 (s, 3H, M), 4.03

1H), 4.78 (d, J = 5.6, 1H), 5.23 (d, J = 5.6, 1H), 6.01 (t, J = 5.6, 1H),

(

6

s, 3H, m), 5.02 (t, J = 6.0, 1H, m), 5.18 (t, J = 5.6, 1H, M), 5.42 (t, J =

.0, 1H, m), 6.31 (d, J = 6.0, 1H, M), 6.45 (d, J = 6.4, 1H, m), 6.48 (d,

J = 6.0, 1H, M), 6.56 (d, J = 6.0, 1H, m), 6.66 (br, m + M), 6.85−8.52

6.06 (t, J = 6.0, 1H), 6.39 (m, br, 1H), 7.32−7.38 (m, 5H), 7.63−7.72

13

1

(m, 3H), 7.76 (t, J = 7.2, 1H). C{ H} NMR (101 MHz): 18.0 (d,

2

1

J_P_C= 7.3, CH ), 18.5 (d, J = 3.1, CH ), 25.4 (d, J = 25.8, CH),

3

PC

3

PC

3

1

(

m, Ar, 26H). P{ H} NMR (162 MHz): +30.2 (s, M), 33.7 (s, m).

77.76 (s, CH), 77.80 (s, CH), 88.3 (d, J = 15.4, CH), 97.6 (d, J = 2.1,

CH), 101.1 (d, J = 3.1, CH), 110.1 (d, J = 2.7, C), 127.5−146.1 (C,

CH, Ar). ³¹P{ H} NMR (121 MHz): +66.7 (s). Anal.: calcd. for

C H Cl PRu: C 52.95%, H 4.44%; found C 50.48%, H 4.46%.

Anal.: calcd. for C H Cl O PRu: C 59.82%, H 4.72%; found C

5

33

31

2

1

9.05%, H 5.05%.

6

Dichloro(η -methyl benzoate)[(S)-methoxy(2-(2′-naphthyl)-

2

1

21

2

6

phenyl)phenylphosphine]ruthenium(II), 26g. The procedure

was the same as that used to prepare 6a. Starting from phosphinite

2

Dichloro[κP-η -(R)-(2-biphenylyl)ferrocenylphenyl-

phosphine]ruthenium(II), 17c. The procedure was the same as that

used to prepare 9c. Starting from complex 13c (173 mg, 0.23 mmol),

the desired product was obtained as a reddish solid. Yield: 140 mg

(99%).

1g (125 mg, 0.36 mmol), the title product was isolated as an orange

solid. Yield: 106 mg (90%).

IR (ν): 3054, 2947, 2840, 1726 (CO), 1435, 1294, 1275, 1109,

1

3

1

3

=

2

7

(

028, 767, 554, 527, 504. H NMR (400.1 MHz): 3.58 (d, J = 12.0,

IR (ν): 3075, 2955, 2924, 1435, 1163, 1105, 1027, 824, 691, 542,

PH

1

H), 3.91 (s, 3H), 4.89 (t, J = 5.6, 1H), 4.93 (t, J = 6.0, 1H), 5.43 (dt, J

5.6, 3.2, 1H), 6.42 (d, J = 6.8, 2H), 6.94 (s, br, 1H), 7.03 (td, J = 7.6,

493. H NMR (400.1 MHz): 4.01 (s, 1H), 4.21 (s, 5H), 4.33 (s, 1H),

4.50 (s, 1H), 4.71 (s, 1H), 4.95 (d, J = 5.6, 1H), 5.23 (d, J = 5.2, 1H),

5.87 (t, J = 5.6, 1H), 6.08 (t, J = 6.0, 1H), 6.27 (s, br, 1H), 7.37−7.40

.8, 2H), 7.09−7.21 (m, 3H), 7.30−7.38 (m, 2H), 7.41−7.55 (m, 6H),

3

1

13

1

.79 (d, J = 7.6, 1H), 8.77 (ddd, J = 14.8, 7.2, 2.0, 1H). P{ H} NMR

(m, 3H), 7.55−7.63 (m, 6H). C{ H} (101 MHz): 69.4 (d, J = 7.7,

CH), 70.3 (s, CH), 72.3 (d, J = 8.4, CH), 73.7 (d, J = 7.0, CH), 75.0

(d, J = 13.5, CH), 80.6 (s, CH), 81.6 (s, CH), 90.4 (d, J = 15.5, CH),

96.5 (d, J = 2.9, CH), 99.1 (d, J = 4.2, CH), 109.7 (d, J = 3.2, CH),

162 MHz): +112.3 (s). Anal.: calcd. for C H Cl O PRu: C 57.24%,

31 27 2 3

H 4.18%; found C 56.93%, H 4.29%.

6

Dichloro(η -methyl benzoate)[(R)-isopropyl(2-(2′-naphthyl)-

phenyl)phenylphosphine]ruthenium(II), 28g. The procedure was

the same as that used to prepare 6a. Starting from phosphine 25g (100

mg, 0.28 mmol), the title product was isolated as a brownish solid.

Yield: 120 mg (80%).

31

1

126.9−148.4 (C, CH, Ar). P{ H} NMR (162 MHz): +36.8 (s).

HRMS(ESI): calcd. for C H ClFePRu ([M] − Cl), 582.9613; found,

28

23

582.9619. UV−vis (λ (ε)): 380 (2700), 460 (1100).

max

6

Dichloro[κP-η -(S)-methoxyphenyl(2-p-terphenylyl)-

IR (ν): 3054, 2951, 2925, 2869, 1731 (CO), 1632, 1434, 1294,

276, 1110, 769, 700, 525. H NMR (400.1 MHz): 0.89 (dd, J , J

PH HH

phosphine]ruthenium(II), 29d. The procedure was the same as that

used to prepare 9c. Starting from complex 26d (147 mg, 0.21 mmol),

the desired product was obtained as a reddish solid. Yield: 87 mg

(74%).

1

3

1

=

3

18.0, 6.8, 3H), 1.06 (dd, J , J = 15.2, 6.8, 3H), 2.76 (m, 1H),

PH HH

3

.96 (s, 3H), 5.11 (m, 1H), 5.32 (t, J = 5.6, 1H), 5.37 (m, br, 1H), 6.39

d, J = 6.0, 1H), 6.56 (d, J = 6.0, 1H), 7.03 (t, br, J = 7.6, 3H), 7.29 (d,

br, J = 7.6, 1H), 7.22 (m, 1H), 7.38−7.52 (m, 5H), 7.54−7.66 (m,

1

(

IR (ν): 3049, 1434, 1110, 1032, 998, 765, 695, 536, 512. H NMR

3

(400.1 MHz): 3.71 (d, J = 12.8, 3H), 5.25 (d, J = 6.0, 1H), 5.44 (d,

PH

3

1

3

(

H), 7.68−7.81 (m, 2H), 8.16 (dd, J = 12.8, 8.0, 1H). P{ H} NMR

J = 6.0, 1H), 6.25 (d, J = 5.6, 1H), 6.54 (dd, J = 6.0, 1.2, 1H), 7.40−

13

1

162 MHz): +34.2 (s). Anal.: calcd. for C H Cl O PRu: C 59.82%,

7.53 (m, 6H), 7.57−7.75 (m, 6H), 7.88−7.90 (m, 2H). C{ H} (101

33

31

2

H 4.72%; found C 58.72%, H 5.00%.

MHz): 55.4 (d, J = 3.9, CH ), 81.3 (s, CH), 82.3 (s, CH), 96.4 (d, J

PC

3

6

Dichloro[κP-η -(S)-(2-biphenylyl)methoxyphenyl-

phosphine]ruthenium(II), 14c. The procedure was the same as that

used to prepare 9c. Starting from complex 10c (307 mg, 0.5 mmol),

the desired product was obtained as a brown solid. Yield: 193 mg

= 1.7, CH), 101.9 (d, J = 4.6, CH), 109.4 (d, J = 17.1, C), 110.2 (d, J =

31

1

3.4, C), 126.5−148.9 (C, CH, Ar). P{ H} NMR (162 MHz): +141.6

(s). HRMS(ESI): calcd. for C H ClOPRu ([M] − Cl), 505.0056;

25

21

found, 505.0062.

6

(

82%).

IR (ν): 3055, 2938, 1587, 1434, 1397, 1277, 1241, 1133, 1110,

Dichloro[κP-η -(R)-methylphenyl(2-p-terphenylyl)-

phosphine]ruthenium(II), 30d. The procedure was the same as that

used to prepare 9c. Starting from complex 27d (100 mg, 0.15 mmol),

the desired product was obtained as a reddish solid. Yield: 39 mg

(49%).

1

3

1

3

025, 770, 690, 530, 512. H NMR (400.1 MHz): 3.68 (d, J = 13.2,

PH

H), 5.11 (d, J = 5.2, 1H), 5.34 (d, J = 4.8, 1H), 6.11 (s, br, 1H), 6.30

(

s, br, 1H), 6.56 (s, br, 1H), 7.38−7.42 (m, 3H), 7.57−7.69 (m, 6H).

1

3

1

C{ H} NMR (101 MHz): 55.1 (d, J = 4.0, CH ), 80.6 (s, CH), 81.7

IR (ν): 3048, 2913, 1433, 1104, 885, 762, 696, 508, 474. H NMR

3

2

(

4

s, CH), 92.7 (d, J = 15.6, CH), 99.5 (d, J = 2.8, CH), 103.0 (d, J =

(400.1 MHz): 2.15 (d, JPH = 12.0, 3H), 5.16 (d, J = 5.6, 2H), 6.02 (d,

31

1

.1, CH), 111.8 (d, J = 3.0, C), 126.5−148.1 (C, CH, Ar). P{ H}

J = 5.6, 1H), 6.42 (d, J = 5.6, H), 7.34−7.49 (m, 8H), 7.58−7.74 (m,

1

3

1

NMR (121 MHz): +140.4 (s). Anal.: calcd. for C H Cl OPRu: C

4

4H), 7.86−7.89 (m, 2H). C{ H} NMR (101 MHz): 13.4 (d, JPC =

19

17

2

9.15%, H 3.69%; found C 48.07%, H 3.90%.

31.9, CH

), 79.9 (s, 2CH), 94.2 (s, CH), 98.9 (d, J = 4.3, CH), 106.8

3

6

Dichloro[κP-ηη -(R)-(2-biphenylyl)methylphenylphosphine]-

(d, J = 15.4, C), 108.9 (d, J = 2.9, C), 127.2−145.2 (C, CH, Ar).

3

1

ruthenium(II), 15c. The procedure was the same as that used to

prepare 9c. Starting from complex 11c (299 mg, 0.5 mmol), the

desired product was obtained as a brown solid. Yield: 199 mg (86%).

IR (ν): 3052, 2973, 2905, 1433, 892, 866, 842, 734, 692, 508, 474,

P{ H} NMR (162 MHz): +43.7 (s). HRMS(ESI): calcd. for

C H ClPRu ([M] − Cl), 489.0107; found, 489.0116. UV−vis (λ

25

21

max

(ε)): 366 (1800), 490 (320).

6

Dichloro[κP-η -(R)-isopropylphenyl(2-p-terphenylyl)-

phosphine]ruthenium(II), 31d. The procedure was the same as that

used to prepare 9c. Starting from complex 28d (100 mg, 0.14 mmol),

the desired product was obtained as a reddish solid. Yield: 17 mg

(22%).

1

2

4

5

1

60. H NMR (400.1 MHz): 2.14 (d, J = 11.6, 3H), 5.04 (d, J =

PH

.6, 1H), 5.08 (d, J = 5.2, 1H), 5.85 (t, J = 5.6, 1H), 6.18 (t, J = 6.0,

H), 6.39 (s, br, 1H), 7.34−7.38 (m, 5H), 7.55−7.70 (m, 4 H).

13

1

C{ H} NMR (101 MHz): 13.5 (d, J = 32.4, CH ), 79.38 (s, CH),

3

1

7

=

9.40 (s, CH), 89.8 (d, J = 15.6, CH), 96.5 (d, J = 1.9, CH), 100.6 (d, J

IR (ν): 3056, 1434, 1113, 756, 693, 618, 504, 455. H NMR (400.1

31

1

3

4.3, CH), 110.4 (d, J = 2.8, C), 127.0−144.9 (C, CH, Ar). P{ H}

MHz): 1.15 (dd, JPH, JHH = 19.6, 6.8, 3H), 1.28 (dd, JPH, JHH = 13.2,

7.2, 3H), 3.25 (hexaplet, JHH = 7.2, 1H), 4.88 (d, J = 5.6, 1H), 5.32 (d,

3

NMR (121 MHz): +43.2 (s). Anal.: calcd. for C H Cl PRu: C

5

(

19

17

2

0.91%, H 3.82%; found C 49.17%, H 3.99%. UV−vis (λ_m_a_x(ε)): 366

J = 5.6, 1H), 6.21 (d, J = 6.0, 1H), 6.26 (d, J = 5.6, 1H), 7.34−7.49 (m,

13

1

1650), 440 (500).

Dichloro[κP-η -(R)-(2-biphenylyl)isopropylphenyl-

8H), 7.64−7.81 (m, 4H), 7.89−7.91 (m, 2H). C{ H} NMR (101

6

2

MHz): 18.5 (d, JPC = 7.0, CH

), 18.6 (d, JPC = 3.2, CH

), 26.1 (d,

3

1

phosphine]ruthenium(II), 16c. The procedure was the same as that

J_P_C= 25.9, CH), 77.9 (s, CH), 78.0 (s, CH), 96.3 (s, CH), 99.7 (s,

9

91

DOI: 10.1021/acs.organomet.5b00018

Organometallics 2015, 34, 973−994

Organometallics

Article

CH), 104.8 (d, J = 15.4, C), 108.9 (d, J = 16.0, C), 127.7−145.9 (C,

the desired product was obtained as a brown solid. Yield: 30 mg

(74%).

3

1

CH, Ar). P{ H} NMR (162 MHz): +67.2 (s). HRMS(ESI): calcd.

for C H ClPRu ([M] − Cl), 517.0402; found, 517.0428.

IR (ν): 3055, 2939, 1471, 1436, 1133, 1100, 1025, 764, 694, 580,

27

25

6

1

3

Dichloro[κP-η -(S)-methoxyphenyl(2-m-terphenylyl)-

phosphine]ruthenium(II), 29e. The procedure was the same as that

used to prepare 9c. Starting from complex 26e (100 mg, 0.15 mmol),

the desired product was obtained as a reddish solid. Yield: 60 mg

534, 517. H NMR (400.1 MHz): 3.66 (d, J = 12.8, 3H, M), 3.82

PH

3

(d, J = 12.8, 3H, m), 5.43 (ddd, J = 6.0, 3.6, 0.8, 1H, M), 5.65 (s,

PH

1H, m), 5.74 (d, J = 6.0, 1H, m), 5.93 (s, 1H, M), 6.29 (d, J = 5.6, 1H,

M), 6.31 (d, J = 6.0, 1H, m), 7.33−7.99 (m, Ar, 13 H m + M).

13

1

2

(

75%).

IR (ν): 3059, 2935, 1435, 1108, 770, 693, 535, 517. H NMR

C{ H} NMR (101 MHz): 55.7 (d, J = 3.0, CH , m), 56.2 (d, J

PC 3 PC

1

= 4.0, CH , M), 80.1 (s, CH, m), 83.5 (d, J = 1.7, CH, M), 86.7 (s,

3

(

400.1 MHz): 3.63 (d, J = 12.8, 3H), 3.71 (d, J = 13.2, 3H), 5.23

CH, M), 87.5 (s, CH, m), 87.7 (s, CH, M), 90.4 (s, CH, m), 107.0 (d,

J = 4.7, C, M), 112.1 (d, J = 11.2, C, M), 117.6 (d, J = 7.9, C, M),

126.0−135.5 (C, CH, Ar), 143.1 (d, J = 24.0, C), 149.2 (d, J = 70.0,

C). ³¹P{ H} NMR (162 MHz): +151.4 (s, m), +154.1 (s, M).

HRMS(ESI): calcd. for C H ClOPRu ([M] − Cl), 478.9900; found,

PH

s, 1H), 5.29 (d, J = 5.6, 1H), 5.43 (s, 1H), 5.51 (d, J = 5.6, 1H), 6.12

t, J = 6.0, 1H), 6.32 (t, J = 6.0, 1H), 6.68 (d, J = 6.4, 1H), 6.71 (d, J =

1

6

.4, 1H), 7.28 (d, J = 2.8, 1H), 7.31 (d, J = 2.8, 1H), 7.35 (dd, J = 7.6,

.6, 1H), 7.44−7.53 (m, 11H), 7.57−7.76 (m, 12H), 7.80 (m, 2H).

1

23

19

13

1

2

C{ H} NMR (101 MHz): 55.0 (d, J = 4.0, CH ), 55.3 (d, J = 3.9,

478.9918.

PC

3

6

CH ), 78.4 (s, CH), 79.3 (s, CH), 80.5 (s, CH), 81.7 (s, CH), 91.6 (d,

Dichloro[κP-η -(R)-isopropyl(2-(2′-naphthyl)phenyl)phenyl-

phosphine]ruthenium(II), 31g. The procedure was the same as that

used to prepare 9c. Starting from complex 28g (60 mg, 0.09 mmol),

the desired product was obtained as a brown solid. Yield: 40 mg

(84%).

3

J = 17.0, CH), 91.9 (d, J = 17.0, CH), 97.1 (d, J = 2.2, CH), 101.1 (d, J

=

3.9, CH), 111.76 (d, J = 2.9, C), 111.80 (d, J = 3.3, C), 115.5 (d, J =

31

1

3.6, C), 120.0 (d, J = 5.4, C), 126.5−148.8 (C, CH, Ar). P{ H}

NMR (162 MHz): +140.9 (s), +141.6 (s). HRMS(ESI): calcd. for

C H ClOPRu ([M] − Cl), 505.0056; found, 505.0056.

IR (ν): 3054, 2959, 2925, 2868, 1632, 1470, 1435, 1240, 1099,

040, 880, 763, 695, 577, 525, 512. H NMR (400.1 MHz): 1.15−1.35

(m, 6H + 6H (m + M)), 2.99 (m, 1H), 3.32 (m, 1H), 5.03 (dd, J = 6.0,

25

21

1

6

1

Dichloro[κP-η -(R)-isopropylphenyl(2-m-terphenylyl)-

phosphine]ruthenium(II), 31e. The procedure was the same as that

used to prepare 9c. Starting from complex 28e (90 mg, 0.13 mmol),

the desired product was obtained as a reddish solid. Yield: 50 mg

3.6, 1H), 5.47 (s, 1H), 5.61 (d, br, J = 6.4, 1H), 5.81 (s, 1H), 6.09 (d, J

13

1

= 5.6, 1H), 6.28 (d, J = 5.6, 1H), 7.27−7.95 (m, 13H, Ar). C{ H}

2

(

71%).

IR (ν): 3055, 1470, 1384, 767, 695, 528. H NMR (400.1 MHz):

NMR (101 MHz): 17.7 (s, CH

3

), 18.4 (d, JPC = 7.4, CH

3

), 19.3 (d,

PC = 1.9, CH ), 19.7 (d, JPC = 2.6, CH ), 29.3 (d, JPC = 31.2, CH),

3 3

1

2

1

J

3

1

3

1

6

.01 (dd, J , J = 19.6, 7.2, 3H, M), 1.20 (dd, J , J = 19.6, 6.8,

29.7 (d, J = 27.7, CH), 76.5 (s, CH), 79.9 (s, CH), 83.3 (d, J = 1.5,

PH

HH

PH

HH

PC

3

H, m), 1.25 (dd, J , J = 13.6, 7.2, 3H, M), 1.30 (dd, J , J

3.6, 7.2, 3H, m), 3.22 (septet, J = 6.8, 1H), 3.24 (septet, J

=

CH), 86.2 (s, CH), 87.7 (s, CH), 89.6 (s, CH), 106.36 (d, J = 0.7, C),

106.39 (d, J = 1.0, C), 108.0 (d, J = 9.9, C), 109.9 (d, J = 8.5, C), 115.1

(d, J = 6.6, C), 115.6 (d, J = 6.0, C), 126.4−135.6 (C, CH, Ar), 138.4

(d, J = 45.0, C), 142.6 (d, J = 48.0, C), 145.4 (d, J = 17.0, C), 147.2 (d,

J = 19.0, C). ³¹P{ H} NMR (162 MHz): +74.1 (s), +85.2 (s).

PH

HH

PH

HH

3

HH

.8, 1H), 4.90 (s, br, 1H, m), 4.91 (d, J = 4.4, 1H, M), 5.35 (s, br, 1H,

M), 5.41 (d, J = 5.6, 1H, m), 6.06 (t, J = 6.0, 1H, m), 6.10 (t, J = 5.6,

H, m), 6.52 (d, J = 6.0, 1H, m), 6.58 (d, J = 6.0, 1H, M), 7.27−7.78

1

3

1

(

m, Ar, 14 H m + M). C{ H} NMR (101 MHz): 18.0−18.8 (m, br,

HRMS(ESI): calcd. for C25H23ClPRu ([M] − Cl), 491.0263; found,

491.0280.

1

CH ), 25.2 (d, J = 25.9, CH, M), 25.9 (d, J = 26.1, CH, m), 75.2

3

PC

(

s, CH, M), 75.8 (s, CH, m), 77.5 (s, CH, M), 77.9 (s, CH, m), 87.2

d, J = 15.0, CH, M), 87.9 (d, J = 14.5, CH, m), 96.2 (d, J = 1.7, CH,

General Procedures for TH Catalytic Runs. A typical transfer

hydrogenation run was performed as follows. A 100 mL Schlenk ﬂask

was charged with the ruthenium precursor (0.02 mmol) and potassium

tert-butoxide (11.2 mg, 0.1 mmol) and was purged with three vacuum/

argon cycles. Under a gentle ﬂow of argon, 25 mL of 2-propanol was

added and the ﬂask was heated to reﬂux (85 °C) for 15 min. After that

time, acetophenone (0.468 mL, 4.0 mmol) was rapidly added to start

the catalytic run. The reaction was monitored at the allotted times by

taking aliquots of around 0.1 mL and analyzing them by GC.

m), 99.5 (d, J = 3.0, CH, M), 109.7 (d, J = 2.6, C, m), 110.2 (d, J = 2.4,

C, M), 113.4 (d, J = 2.7, C, M), 116.8 (d, J = 3.7, C, m), 127.6−146.4

3

1

(

C, CH, Ar). P{ H} NMR (162 MHz): +66.9 (s, M), +67.5 (s, m).

HRMS(ESI): calcd. for C H ClPRu ([M] − Cl), 517.0402; found,

5

27

25

17.0422.

6

Dichloro[κP-η -(S)-methoxy(2-(1′-naphthyl)phenyl)phenyl-

phosphine]ruthenium(II), 29f. The procedure was the same as that

used to prepare 9c. Starting from complex 26f (100 mg, 0.15 mmol),

the desired product was obtained as a dark purple solid. Yield: 75 mg

ASSOCIATED CONTENT

(

94%).

■

1

IR (ν): 3051, 2936, 1435, 1107, 1030, 763, 693, 532. H NMR

400.1 MHz): 3.16 (d, J = 12.8, 3H), 3.50 (d, J = 12.8, 3H), 5.07

*

S

Supporting Information

3

(

PH

Full catalytic results, conformational analysis of 23f, NMR

spectra of selected compounds, and CIF ﬁles for 5a, 9c, 23f,

26d, 27d, 31d, and 26g . This material is available free of charge

via the Internet at http://pubs.acs.org. CCDC 1037902−

d, J = 5.2, 1H), 5.36 (d, J = 5.6, 1H), 6.60 (t, J = 6.4, 1H), 6.73 (d, J =

8

5

.4, 1H), 6.80 (t, J = 6.0, 1H), 7.05−7.43 (m, 14H), 7.64−7.70 (m,

31 1

H), 7.74−7.81 (m, 4H), 7.87−7.91 (m, 2H), 8.03 (m, 1H). P{ H}

NMR (162 MHz): +141.9 (s), 144.5 (s). HRMS(ESI): calcd. for

C H ClOPRu ([M] − Cl), 478.9900; found, 478.9898.

1

037908 contain supplementary crystallographic data for this

2

3

19

6

Dichloro[κP-η -(R)-isopropyl(2-(1′-naphthyl)phenyl)phenyl-

paper. These data can be obtained free of charge from The

Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.

uk/data_request/cif.

phosphine]ruthenium(II), 31f. The procedure was the same as that

used to prepare 9c. Starting from complex 28f (200 mg, 0.3 mmol),

the desired product was obtained as a reddish solid. Yield: 157 mg

(

98%).

IR (ν): 3054, 2960, 1434, 1186, 762, 576, 531. H NMR (400.1

1

AUTHOR INFORMATION

■

3

MHz): 0.99 (dd, J , J = 19.6, 6.8, 3H, M), 1.09 (dd, J , J

1

(

=

PH

HH

PH

HH

Notes

9.6, 6.8, 3H, m), 1.18−1.29 (m, 6H, m + M), 3.02 (m, 1H, m), 3.11

3

The authors declare no competing ﬁnancial interest.

septet, J = 6.8, 1H, M), 4.82 (d, J = 5.2, 1H, M), 5.28 (d, J = 4.8,

HH

1

H, m), 6.42 (br, t, 1H, M), 6.52 (br, t, 1H, m), 6.59 (d, J = 8.8, 1H,

3

1

m), 6.80−8.00 (m, 13H, Ar). P{ H} NMR (162 MHz): +68.2 (s).

ACKNOWLEDGMENTS

■

HRMS(ESI): calcd. for C H ClPRu ([M] − Cl), 491.0263; found,

25

23

We thank the Ministerio de Ciencia e Innovacion

́

(MICINN,

491.0276.

6

grant number CTQ2010-15292) for ﬁnancial support of this

work. We also thank Prof. Manel Martınez for spectrophoto-

metrical measurements of Ru complexes.

Dichloro[κP-η -(S)-methoxy(2-(2′-naphthyl)phenyl)phenyl-

phosphine]ruthenium(II), 29g. The procedure was the same as that

used to prepare 9c. Starting from complex 26g (50 mg, 0.08 mmol),

́

9

92

DOI: 10.1021/acs.organomet.5b00018

Organometallics 2015, 34, 973−994

Organometallics

Article

(

12) (a) Stoop, R. M.; Mezzetti, A.; Spindler, F. Organometallics

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Mild photochemical tethering of [RuCl2(η6-arene)P?] complexes with P -stereogenic 2-biphenylylphosphines

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