Easily accessible chiral P,N-bidentate aryl phosphites, their complexation and application in enantioselective allylic alkylation, sulfonylation and hydrosilylation

Article abstract of DOI:10.1002/1099-0682(200206)2002:6<1367::aid-ejic1367>3.0.co;2-f

New chiral P,N-hybrid aryl phosphites have been obtained by one-step phosphorylation of amino and imino alcohols. Complexation of the new ligands with [Rh(CO)₂Cl]₂, [Pd(COD)Cl₂] and [Pd(allyl)Cl]₂ was found to give chelate complexes [Rh(CO)Cl(Bη2-pn∩N)], [PdCl₂(Bη2-pn∩N)] and [Pd-(allyl) (Bη²-pn∩N)]⁺Cl^-, respectively. With these new P,N-ligands, up to 82percent ee enantioselectivity was achieved in the Pd-catalysed alkylation of ethyl 3-penten-2-yl carbonate with dimethyl malonate, up to 80percent ee in the Pd-catalysed sulfonylation of methyl 3-penten-2-yl carbonate with sodium p -toluenesulfinate, and up to 50percent ee in the Rh-catalysed hydrosilylation of acetophenone with diphenylsilane. ? Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002.

Full text of DOI:10.1002/1099-0682(200206)2002:6<1367::aid-ejic1367>3.0.co;2-f

FULL PAPER
Easily Accessible Chiral P,N-Bidentate Aryl Phosphites, Their Complexation
and Application in Enantioselective Allylic Alkylation, Sulfonylation and
Hydrosilylation
Konstantin N. Gavrilov,[a] Oleg G. Bondarev,[b] Roman V. Lebedev,[b] Alexei A. Shiryaev,[a]
Sergey E. Lyubimov,[a] Alexei I. Polosukhin,[b] Gennady V. Grintselev-Knyazev,[b]
Konstantin A. Lyssenko,[b] Sergey K. Moiseev,[b] Nikolay S. Ikonnikov,[b] Valery N. Kalinin,[b]
Vladim A. Davankov,[b] Andrei V. Korostylev,*[c] and Hans-Joachim Gais[d]
Keywords: Aryl phosphites / N,P ligands / Palladium / Allylation / Rhodium / Hydrosilylation
New chiral P,N-hybrid aryl phosphites have been obtained
by one-step phosphorylation of amino and imino alcohols.
Complexation of the new ligands with [Rh(CO)2Cl]2,
[Pd(COD)Cl2] and [Pd(allyl)Cl]2 was found to give chelate
complexes [Rh(CO)Cl(η2-PʝN)], [PdCl2(η2-PʝN)] and [Pd-
(allyl)(η2-PʝN)]+Cl−, respectively. With these new P,N-li-
Pd-catalysed alkylation of ethyl 3-penten-2-yl carbonate
with dimethyl malonate, up to 80% ee in the Pd-catalysed
sulfonylation of methyl 3-penten-2-yl carbonate with sodium
p-toluenesulfinate, and up to 50% ee in the Rh-catalysed hy-
drosilylation of acetophenone with diphenylsilane.
( Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany,
gands, up to 82% ee enantioselectivity was achieved in the 2002)
Introduction
structure, normally constructed with the aid of effective
chiral inductors such as BINOL, TADDOL, (1R,2R)-1,2-
N,NЈ-bis(p-toluenesulfonylamino)-1,2-diphenylethane, (S)-
2-(anilinomethyl)pyrrolidine etc.[1Ϫ9] Only one example[10]
of the use of an achiral biphenol is known; the phosphi-
tooxazoline derived from it is a phosphacyclic compound
as well. We have recently reported syntheses of several
chiral P,N-phosphites with acyclic phosphorus donor
centres.[11,12]
Chiral P,N-bidentate compounds are one of the leading
ligand groups in modern asymmetric catalysis.[1Ϫ3] Most
such systems are phosphanes in nature, but phosphite-type
P,N-hybrid ligands are acquiring progressively growing im-
portance because of their synthetic availability, high π-acid-
ity of the phosphorus atom and high resistance to oxidative
destruction. In general, the presence of oxygen and/or nitro-
gen atoms in the first coordination sphere of the phos-
phorus atom offers the potential to tune the chemical
stability of ligands, their donor/acceptor properties and
steric demands. This has made it possible to achieve im-
pressive results in catalytic enantioselective allylation, con-
jugate addition of organometallic compounds to enones,
hydrosilylation and hydrogenation reactions.[1Ϫ9] Interest-
ingly, each of the ligands mentioned has a phosphacyclic
[a]
Department of Chemistry, Ryazan State Pedagogic University,
46 Svoboda Str., Ryazan 390000, Russia
[b]
Institute of Organoelement Compounds, Russian Academy of
Sciences,
These gave up to 57% ee in the Pd-catalysed alkylation
of 1,3-diphenylpropen-2-yl acetate with dimethyl malonate,
and up to 61% ee when 3-phenylpropen-2-yl acetate was
used as a substrate. In this article, we describe the synthesis,
complexation with RhI and PdII precursors and catalytic
applications of a new series of P,N-bidentate aryl phos-
phites bearing distant amino or imino groups.
28 Vavilova Str., Moscow 117813, Russia
[c]
Institut für Organische Katalyseforschung an der Universität
Rostock e.V.,
Buchbinderstraße 5Ϫ6, 18055 Rostock, Germany
[d]
Institut für Organische Chemie der Rheinisch-Westfälischen
Technischen Hochschule Aachen,
Professor-Pirlet-Straße 1, 52056 Aachen, Germany
Supporting information for this article is available on the
WWW under http://www.eurjic.com or from the author.
Eur. J. Inorg. Chem. 2002, 1367Ϫ1376  WILEY-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002 1434Ϫ1948/02/0606Ϫ1367 $ 20.00ϩ.50/0
1367

A. V. Korostylev et al.
FULL PAPER
Results and Discussion
known cationic rhodium, iridium[16] and palladium[17] P,N-
chelates. In addition, the reactions between [Rh(CO)2Cl]2
and the compounds bearing cyclic (3bϪ3e) or sterically
hindered acyclic (3f) sp3-nitrogen donor centres produced
some quantities of trans-[Rh(CO)Cl(η1-PʝN)2] complexes,
in which the compounds function as P-monodentate li-
gands. This was shown by their characteristic[13,18] IR and
31P NMR spectroscopic data (the percentage of trans com-
plexes determined by 31P NMR is given in parentheses) for
The new P,N-bidentate aryl phosphites were synthesized
by one-step phosphorylation of the corresponding amino
and imino alcohols with bis(2,6-dimethylphenyl) chloro-
phosphite.
1
3b: δP ϭ 122.8, JP,Rh ϭ 204.9 Hz (8%); for 3c: δP ϭ 121.4,
1JP,Rh ϭ 207.6 Hz, ν(CO) ϭ 1995 cmϪ1 (20%); for 3d: δP ϭ
1
122.1, JP,Rh ϭ 203.5 Hz, ν(CO) ϭ 2000 cmϪ1 (45%); for
1
3e: δP ϭ 124.6, JP,Rh ϭ 205.6 Hz, ν(CO) ϭ 1994 cmϪ1
(30%); for 3f: δP ϭ 122.6, 1JP,Rh ϭ 195.4 Hz, ν(CO) ϭ 1993
cmϪ1 (54%). It was notable that, the higher the steric de-
mands of the aza centre, the larger the amount of
[Rh(CO)Cl(η1-PʝN)2] complex. The reason for this seems
to be an increase in steric hindrance for coordination of
nitrogen atoms and, as a result, a fall in the proportion
of chelate [Rh(CO)Cl(η2-PʝN)] products. To overcome this
effect, the synthesis of complex 4f was performed in a dif-
ferent way, by the exchange reaction previously developed
for P-monodentate ligands.[19]
They divide into two groups: ligands 3aϪ3f, possessing
sp3-hybridized nitrogen atoms, and ligands 3gϪ3m, which
have sp2-hybridized nitrogen atoms. All the compounds
3aϪm are soluble in conventional organic solvents and
stable under dry conditions for several months. On treat-
ment with [Rh(CO)2Cl]2, their neutral carbonyl(chloro)RhI
complexes were obtained.
Imino phosphites 3gϪ3m, independently of their steric
demands, gave chelate products 4gϪ4m only. They are
therefore more typical chelate ligands than amino phos-
phites.
All the ligands 3aϪ3m had highly π-acidic phosphorus
centres. This was proved by the values of the ν(CO) and
1JP,Rh parameters for complexes 4aϪ4m, which are signific-
antly larger than those for the analogous amino phosphane
based complexes (by 30Ϫ35 cmϪ1 and 80Ϫ100 Hz, respect-
ively) and even their aminoalkyl phosphite counterparts (by
6Ϫ10 cmϪ1 and 10Ϫ15 Hz).[13Ϫ15] It is well known that in-
creasing P-centre π-acidity in P,N-bidentate ligands favours
high chemical and optical yields in such catalytic reactions
as allylation, hydroboration/oxidation and hydrosilylation/
oxidation of alkenes, and hydrosilylation of ketones.[1,2]
On the other hand, increasing σ-donor character in the
N-centre results in higher optical yields in hydroboration/
1
The ν(CO) and JP,Rh parameters in their IR and 31P
NMR spectra act as sensitive indicators, which characterise
the mode of complexation of the P,N-ligands and allow the
π-acceptor ability of the phosphorus centre and the degree
of electronic non-symmetry of the ligands to be
estimated.[13Ϫ15]
In general, ligands 3aϪ3m give chelate complexes. Thus, oxidation and hydrosilylation/oxidation of alkenes.[20,21] In
the 1JP,Rh, 1JC,Rh, 2JC,P, ν(CO) and ν(RhϪCl) data for com- this context, a concept of electronically non-symmetric li-
plexes 4aϪ4m (Tables 1 and 2) are in good agreement with gands has been suggested (the higher the π-acceptor ability
the suggested structures.[13,15] Significant (9Ϫ11 ppm) coor- of the P-centre and the σ-donor ability of the N-centre, the
dination shifts ∆δC [ϭ δC(complex) Ϫ δC(ligand)] for the more electronically non-symmetrical the compound).[14]
azomethine carbon atoms in complexes 4i and 4l (Table 2) This parameter can be estimated by the value of ν(CO) in
also attest to the coordination of distant imino groups with the IR spectrum of the carbonyl(chloro) complex
the rhodium atom. However, complexation of some ligands [Rh(CO)Cl(PʝN)]. In particular, for structurally similar
displays special features. Thus, compounds 4eϪ4g, 4j and complexes with identical phosphorus centres and different
4k exist as two or more conformers (Table 1) similarly to nitrogen centres, a compound with a lower value of ν(CO)
1368
Eur. J. Inorg. Chem. 2002, 1367Ϫ1376

Easily Accessible Chiral P, N -Bidentate Aryl Phosphites
FULL PAPER
Table 1. IR and 31P NMR spectroscopic data for complexes 4a؊m (in CHCl3)
Compound
IR
31P NMR
1JP,Rh
ν(CO)
ν(RhϪCl)
δP
[cmϪ1
]
[cmϪ1
]
[Hz][a]
4a
4b
4c
4d
4e
4f
2031
2032
2028
2028
2029
2024
2034
2024
2024
2028
2024
2026
2025
295
290
288
289
291
280
290
288
287
287
286
290
291
119.4
125.6
122.6
118.7
121.4, 122.6
120.1, 118.5
133.6, 129.7, 110.9
125.8
288.6
287.5
285.9
287.4
290.0 (80%), 287.5 (20%)
288.6 (70%), 288.1 (30%)
287.4 (83%), 273.2 (10%), 300.0 (7%)
273.4
4g
4h
4i
125.3
275.5
4j
122.8, 122.5
123.3, 116.4
121.8
276.4 (85%), 278.0 (15%)
278.4 (73%), 274.7 (27%)
279.8
279.4
4k
4l
4m
121.9
[a]
Percentage of each diastereomer of the complex
Table 2. 13C NMR spectroscopic data for compounds 3i, 4i, 5i and 3l, 4l, 5l (in CDCl3), δC (JC,P [Hz])
Compound HCϭ
CAr
NCH
75.8
OCH2
64.1
N(CH3)2
39.9
CH
CH2
25.1
CH3(Ar)
CH3
3i
160.9
110.7Ϫ148.9
36.6
17.42, 17.46,
17.52, 17.58
17.8, 18.2
11.0, 15.7
4i[a]
5i
170.1
170.8
109.9Ϫ153.0
110.4Ϫ153.6
75.2
73.7
68.5
39.5
39.6
37.8
37.2
25.1
25.0
10.2, 13.6
10.2, 13.4
69.2
17.7, 18.1
(2J ϭ 2.6)
HCϭ
161.2
171.7
173.7
CAr
NCH
Fc (ipso)
80.6
Fc
Fc (Cp) OCH2
CH CH3
CH3(Ar)
3l
123.8Ϫ149.0
124.4Ϫ149.2
125.0Ϫ148.4
77.5
68.3, 68.5,
69.97, 70.03
71.7, 71.8,
73.0, 75.6
70.7, 72.8,
73.9, 74.5
68.8
69.8
69.9
63.9
29.7 18.9, 19.9 17.59, 17.64
30.8 18.5, 20.8 18.1, 18.4
30.0 17.6, 20.1 17.49, 17.53
(3J ϭ 3.1)
77.0
4l[b]
5l
75.4
67.5
(2J ϭ 5.0)
67.7
76.2
74.0
(2J ϭ 4.3)
[a]
2
[b]
The resonance of the carbonyl-type carbon atom: δC ϭ 187.62 (1JC,Rh ϭ 71.1, JC,P ϭ 17.3 Hz).
The resonance of the carbonyl-
type carbon atom: δC ϭ 187.42 (1JC,Rh ϭ 71.4, JC,P ϭ 18.1 Hz).
2
possesses a more active σ-donor nitrogen-containing centre suggested mode of coordination. In particular, the δP values
and hence is more electronically non-symmetric.[14,15] From for complexes 5i and 5l (Table 3) are typical for six-mem-
this point of view, imino phosphites are the most electronic- bered palladacycles based on P,N-bidentate phosphites with
ally non-symmetric ligands among compounds 3aϪ3m acyclic phosphorus centres.[11,22] Large coordination shifts
(Table 1). The exceptions are amino phosphite 4f, bearing ∆δC, similar to those seen in the rhodium complexes 4i and
an dibenzylamino group, and the imino phosphites 3g and 4l, were observed for the azomethine carbon atoms in com-
3j. However, compound 3g has a slightly different phos- plexes 5i and 5l (Table 2). Two equally intense ν(PdϪCl)
phorus centre and is actually a triaryl phosphite (unlike the bands in the far IR regions of 5i and 5l (Table 3) resulted
other ligands), while ligand 3j has an additional sulfur atom from the cis configuration of chloro ligands and different
in its structure. Analogously to complexation with RhI, the trans influences of phosphorus and nitrogen atoms.
new P,N-hybrid aryl phosphites form metal chelates with
PdII.
Table 3. IR and 31P NMR spectroscopic data for palladium com-
plexes 5i, 5l and 6
Compound
ν(PdϪCl) (nujol, CsI) [cmϪ1
]
δP (CDCl3)
5i
5l
6
342, 288
336, 292
Ϫ
77.2
74.1
132.7
The IR and NMR spectroscopic data for the obtained
complexes, shown in Tables 2 and 3, strongly supported the
Eur. J. Inorg. Chem. 2002, 1367Ϫ1376
1369

A. V. Korostylev et al.
FULL PAPER
In order to investigate details of the complex geometry,
complexes 4i, 5i and 5l were studied by single-crystal X-ray
diffraction (see Figures 1, 2 and 3, Table 4). Comparison
of the crystal packings of 4i and 5i revealed that the two
compounds were isostructural. The principal geometry of
the complexes is therefore only very slightly dependent on
the nature of the metal centre and the terminal ligands. In
all the complexes, the metal atoms are characterized by
square-planar coordination with slightly different degrees
of planarity. The maximum deviations from the mean plane
˚
are 0.15, 0.12 and 0.08 A for 4i, 5i and 5l, respectively.
Figure 3. General view of complex 5l and numbering scheme
˚
Table 4. Selected bond lengths [A] and angles [°] for 4i, 5i and 5l
4i
5i
5l
Figure 1. General view of complex 4i and numbering scheme
M(1)ϪC(32)
M(1)ϪN(1)
M(1)ϪP(1)
M(1)ϪCl(1)
M(1)ϪCl(2)
P(1)ϪO(1)
P(1)ϪO(2)
P(1)ϪO(3)
1.804(10)
2.111(7)
2.171(2)
2.3792(19)
Ϫ
1.580(5)
1.619(5)
1.605(4)
1.266(8)
1.426(9)
91.3(2)
Ϫ
Ϫ
2.063(3)
2.1983(10)
2.3656(9)
2.2928(9)
1.571(2)
1.588(2)
1.590(3)
1.282(4)
1.442(5)
Ϫ
91.15(3)
90.60(7)
90.79(7)
88.17(3)
113.79(10)
116.41(10)
118.85(10)
116.1(2)
117.2(3)
126.6(2)
2.027(4)
2.2030(17)
2.3572(16)
2.2919(16)
1.579(4)
1.594(3)
1.576(4)
1.281(6)
1.440(7)
Ϫ
90.81(6)
84.84(13)
91.91(13)
92.49(6)
107.35(15)
114.59(15)
124.67(15)
114.7(3)
116.0(4)
129.0(4)
N(1)ϪC(7)
C(7)ϪC(8)
C(32)ϪM(1)ϪP(1)
Cl(1)ϪM(1)ϪCl(2)
N(1)ϪM(1)ϪP(1)
N(1)ϪM(1)ϪCl(1)
P(1)ϪPd(1)ϪCl(2)
O(1)ϪP(1)ϪM(1)
O(2)ϪP(1)ϪM(1)
O(3)ϪP(1)ϪM(1)
C(2)ϪN(1)ϪM(1)
C(7)ϪN(1)ϪC(2)
C(7)ϪN(1)ϪM(1)
Ϫ
89.27(14)
90.12(14)
Ϫ
116.2(2)
117.71(17)
120.02(16)
115.3(5)
115.4(7)
129.0(4)
Figure 2. General view of complex 5i and numbering scheme
The conformations of the six-membered metallacycles in
the investigated compounds are far from regular, and can
be described as distorted chairs in 4i and 5i and a distorted
boat in 5l. The difference in the conformation type seems
to result from steric overcrowding due to introduction of
the ferrocenyl moiety. In addition, the presence of the ferro-
cenyl substituent gives rise to significant changes in the mu-
tual orientation of the 2,6-dimethylphenyl rings, with one
of them approximately parallel to the Cp ring. Such an ori-
entation of the C(8)ϪC(12) and C(26)ϪC(31) rings pro-
ally unaffected. The ferrocene is characterized by the ec-
lipsed conformation, with practically equal Fe(1)Ϫcentroid
˚
distances, 1.657 and 1.646 A for the C(8)ϪC(12) and the
C(13)ϪC(17) rings. In addition to the neutral dichloropalla-
dium complexes, cationic complex 6 was obtained with li-
gand 3m.
˚
duces a decrease in the interplane separation to 3.32 A, and
could be regarded as an intramolecular stacking interac-
tion. Despite this possible intramolecular stacking interac-
The 31P and 13C NMR spectra of complex 6 (see Exp.
tion, however, the geometry of the ferrocene moiety is actu- Sect. and Table 3) contained only one set of resonances, ex-
1370
Eur. J. Inorg. Chem. 2002, 1367Ϫ1376

Easily Accessible Chiral P, N -Bidentate Aryl Phosphites
FULL PAPER
plicable either by the presence of only one of the possible
4. Optical yields depended significantly on the solvent
exo and endo isomers or by their fast interconversion (see used and the temperature. Notably, for ligand 3m the latter
ref.[2], refs. cited therein and refs.[23,24]). It is noteworthy that correlation was nonlinear in character (Entries 11Ϫ14).
the Eb(Cl2P) value of 198.4 eV in the XPS spectrum of
compound 6 is close to the highest limit for chlorine an- a catalytic system much (compare Entries 19 and 22).
ions.[25] Furthermore, the PD mass spectrum of complex 6
What should be discussed separately are significant in-
5. The L*/Pd ratio did not influence the effectiveness of
shows a rarely observable molecular ion peak (usually only creases in ee values on going from ligand 3h to 3e (by 14%,
the [M Ϫ Cl]ϩ peak is observed). These facts allowed us to Entries 4 and 9) and, especially, from 3i to 3m (by 23%,
1
conclude that complex 6 exists as a contact ion pair.[26]
Entries 6 and 19). Since the ν(CO) and JP,Rh values for
Some of the new P,N-(aryl phosphites) were tested in the their rhodium complexes [Rh(CO)Cl(η2-PʝN)] are practic-
palladium-catalysed allylic alkylation of ethyl 3-penten-2-yl ally identical (Table 1), the electronic characteristics of the
carbonate with dimethyl malonate (Scheme 1, R ϭ Et). The ligands (including the degree of electronic non-symmetry)
results are shown in Table 5. They allow the following con- are very much the same. Therefore, the effect is steric in
clusions to be made:
nature, and the steric parameters of the ligands are indeed
responsible for the difference in the optical yields in the
catalytic reaction. Ligands 3i and 3l have similar structures
and only the ϪNϭCHR fragments are different. To estim-
ate the bulkiness of the substituents, the cone angles θR for
the p-C6H4NMe2 and Cp2Fe fragments were calculated by
constructing appropriate computer models and from the X-
ray data. The calculated cone angle for the Cp2Fe fragment
[θR ϭ 159° (AM1), 157° (X-ray, complex 5l)] is significantly
Scheme 1
larger than the angle for the p-C6H4NMe2 fragment [θR
ϭ
Table 5. Enantioselective allylic alkylation of 3-penten-2-yl carbon-
ate with dimethyl malonate according to Scheme 1 (L*/Pd ϭ 2);
DCM ϭ dichloromethane
133° (AM1), 129° (X-ray, complex 5i)]. Hence, bulky sub-
stituents attached to the imine group of the P,N-(imino
phosphite) ligands are likely to afford higher optical yields
in the catalytic reaction.
Entry L*
Solvent
T [°C]
Yield (%)[a] ee (%)[b]
The catalytic effectiveness shown by the catalytic system
with ligand 3m was comparatively high, since 1,3-dimethyl-
substituted allylic substrates belong to a group termed ‘‘un-
manageable’’.[27] There are only two known P,N-ligands
that also give more than 80% enantioselectivity, one of the
new generation phosphanyloxazolines (70Ϫ90% ee)[28] and
1
2
3
4
5
6
7
8
3b
3d
3f
3h
3i
3i
3j
3k
3l
3l
THF
THF
THF
THF
THF
DCM
DCM
THF
THF
THF
THF
THF
THF
THF
CH3CN
DMF
room temp. 90
room temp. 35
room temp. 30
room temp. 60
room temp. 50
room temp. 85
room temp. 90
room temp. 65
room temp. 75
11 (S)
2 (R)
4 (S)
24 (S)
58 (S)
57 (R)
13 (R)
52 (S)
38 (S)
21 (S)
49 (R)
69 (R)
77 (R)
52 (R)
54 (R)
45 (R)
53 (R)
61 (R)
80 (R)
81 (R)
76 (R)
82 (R)
a
2-(phosphanylaryl)pyridine-derived ligand (Scheme 1,
R ϭ Me, iPr, Ph, 78Ϫ93% ee).[27] It should be noted that
the mentioned high enantioselectivities were achieved by
thorough optimization of the reaction conditions at a low
temperature (Ϫ25 to Ϫ40 °C) and sometimes by addition
of crown ethers.[27,28]
9
10
11
12
13
14
15
16
17
18
19
20
21
22
Ϫ18
65
40
65
3m
3m
3m
3m
3m
3m
3m
3m
3m
3m
3m
room temp. 65
5
Ϫ18
70
25
room temp. 55
room temp. 70
Some of the new P,N-bidentate aryl phosphites were
tested in the Pd-catalysed allylic substitution of methyl 3-
penten-2-yl carbonate with NaSO2pTol (Scheme 2). The ob-
tained results are shown in Table 6. It is easy to see that
main tendencies in this catalytic process were similar to
those in the reaction with the malonate nucleophile discus-
sed above. In particular, the highest enantioselectivities were
demonstrated by the ligands with distant imino groups. It is
important to note that the optical yield produced by imino
phosphite 3m (80% ee) was the best so far achieved in the
reaction using P,N-ligands. Helmchen’s phosphanyloxazol-
(CH2OMe)2 room temp. 60
toluene
DCM
DCM
DCM
room temp. 60
room temp. 80
5
Ϫ18
75
30
3m[c] DCM
room temp. 80
[a] Yield of analytically pure product after column chromatography.
[b]
The ee values were determined by chiral GC (fused silica capil-
[c]
lary column DP-TFA-γ-CD, 90 °C, He, 1.8 bar). L*/Pd ϭ 1.
1. Systems with sp3-hybridized nitrogen atoms were not ines, the most effective previously described P,N-ligands,
effective (ee Ͻ 11%, Entries 1Ϫ3).
2. Among the imino phosphites, ligands 3i, 3k and 3m
(Entries 5, 8, 22) were the most effective (up to 82% ee).
3. Optical yields greatly depended on the substituent at
the chiral centre, as clearly demonstrated by the homolog-
ous ligands 3h (24% ee) and 3i (58% ee), as well as 3l (38%
ee) and 3m (82% ee).
Scheme 2
Eur. J. Inorg. Chem. 2002, 1367Ϫ1376
1371

A. V. Korostylev et al.
FULL PAPER
gave up to 59% ee.[29] Moreover, unlike phosphanyloxazol-
ines, our ligands did not give rise to the formation of a
sulfinic acid ester as a side product. To the best of our
knowledge, the only ligand giving higher results in this reac-
tion [99% ee, with Pd2(dba)3 as a precatalyst] is one of
Trost’s P,P-bidentate ligands,[30] which form 13-membered
chelate palladium complexes.[31]
µL/min. Spectra were recorded over a mass range of 200Ϫ1200 Da
and were calibrated relative to a mixed PEG standard. The X-ray
photoelectron spectrum (XPS) was measured with a MAC-2 Riber
spectrometer calibrated against Ag lines at 901.5 and 367.9 eV, cor-
rection for the sample charging was performed at C1s ϭ 284.6 eV;
the accuracy of the line maximum determination was Ϯ0.1 eV.
Cone angles θR of the substituents were determined from their con-
formations in the structures H-R obtained by computer calcula-
tions (AM1) and in the X-ray crystal structures of the correspond-
ing complexes by the published approach.[32] Elemental analyses
were performed at the Laboratory of Microanalysis (Institute of
Organoelement Compounds, Moscow). Crystallographic data and
refinement parameters for compounds 4i, 5i and 5l are summarized
in Table 7. The experimental data were collected at 110 K with a
Bruker SMART 1000 CCD area detector by using graphite-mon-
Table 6. Enantioselective allylic sulfonylation of 3-penten-2-yl car-
bonate with NaSO2pTol according to Scheme 2
Entry L* L*/Pd Solvent T [°C]
Yield (%)[a] ee (%)[b]
1
2
3
4
5
6
7
8
3b 2:1
3c 2:1
3i 2:1
3i 2:1[c]
3i 2:1
3i 1:1
3i 1:1
3k 2:1
3k 2:1
3k 1:1
3m 2:1
3m 2:1
3m 2:1[c]
3m 1:1
3m 1:1
THF
THF
THF
THF
THF
THF
DCM
THF
THF
THF
THF
THF
THF
DCM
DCM
room temp. 47
12 (S)
10 (S)
44 (R)
46 (R)
56 (R)
50 (R)
50 (R)
45 (S)
54 (S)
50 (S)
63 (R)
78 (R)
76 (R)
76 (R)
80 (R)
room temp. 22
room temp. 63
room temp. 53
˚
ochromated Mo-Kα radiation (λ ϭ 0.71072 A, ω-scans with 0.3°
steps in ω and 10 s per frame exposure). The absorption correction
was applied semiempirically from equivalents. All the structures
were solved by direct methods and refined by the full-matrix, least-
squares technique against F2 in the anisotropic (H atoms isotropic)
approximation with the SHELXTL 5.1 package. Analysis of the
Fourier density synthesis in 4i showed that the isobutyl group
[C(3)ϪC(6)] was disordered by two positions, which were included
in the refinement with equal occupancies. The absolute configura-
tions in 4i and 5i were determined by use of the Flack parameter.
All hydrogen atoms with the exception of the disordered group
were located from the Fourier synthesis and treated by a mixture
of independent and constrained refinement. CCDC-173440 (4i),
-173441 (5i) and -173442 (5l) contain the supplementary crystallo-
graphic data for this paper. These data can be obtained free of
charge at www.ccdc.cam.ac.uk/conts/retrieving.html or from the
Cambridge Crystallographic Data Centre, 12, Union Road, Cam-
bridge CB2 1EZ, UK [Fax: (internat.) ϩ 44-1223/336-033; E-mail:
deposit@ccdc.cam.ac.uk]. [Rh(CO)2Cl]2,[33] [Pd(COD)Cl2],[34]
[Pd(allyl)Cl]2,[35] amino and imino alcohols 2d,[36] 2f,[37] 2g,[38]
2h,[11] 2l[39] and bis(2,6-dimethylphenyl) chlorophosphite[12] were
synthesized as published. The syntheses of compounds 2iϪk and
2m were performed by techniques similar to that reported.[40] (S)-
(ϩ)-Isoleucinol, ferrocenecarboxaldehyde, 4-(dimethylamino)ben-
zaldehyde and compounds 2a and 2c were purchased from Aldrich;
(1R,2S)-(ϩ)-cis-1-amino-2-indanol was purchased from Fluka.
Amino and imino alcohols 2b (quincoridine, Büchler GmbH),
2cϪf, 2h and 2i were azeotropically dried with benzene and distilled
before use. Compounds 2a, 2g and 2jϪ2m were dried under
vacuum (2 Torr, 3 h) immediately before use.
0
48
room temp. 65
room temp. 59
room temp. 69
9
0
Ϫ20
42
20
10
11
12
13
14
15
room temp. 74
0
0
51
38
room temp. 45
21
0
[a] Yield of analytically pure product after column chromatography.
[b]
The ee values were determined by chiral GC (Lipodex-γ: 2,3-
di-O-pentyl-6-O-methyl-γ-cyclodextrin (25m ϫ 0.8 mm) column).
[c]
Pd2(dba)3ϫCHCl3.
Ligands 3aϪm were also tested in the Rh-catalysed
asymmetric hydrosilylation of acetophenone with di-
phenylsilane (Scheme 3). However, the achieved optical
yields were rather low, with amino phosphites (up to 28%
ee) once again being less effective than imino phosphites 3i
(45% ee) and 3m (50% ee).
Scheme 3
Experimental Section
Synthesis and Characterization
General Comments: All reactions were performed under argon in
(2S,3S)-3-Methyl-2-(pyrrolidin-1-yl)pentan-1-ol (2e): A mixture of
dehydrated solvents. IR spectra were recorded with a Specord M80 1,4-dibromobutane (2.37 mL, 2ϫ10Ϫ2 mol), (S)-(ϩ)-isoleucinol
or Nicolet 750 instrument. 31P, 13C and 1H NMR spectra were
recorded with a Bruker AMX 400 instrument (162.0 MHz for 31P,
(2.34 g, 2ϫ10Ϫ2 mol) and K2CO3 (8.29 g, 6ϫ10Ϫ2 mol) in aceton-
itrile (25 mL) was heated under reflux for 30 h. The mixture was
100.6 MHz for 13C and 400.13 MHz for 1 H). Complete assignment then allowed to cool to room temp. and filtered, and the filter cake
of all the resonances in 13C NMR spectra was achieved by use of
DEPT techniques. Chemical shifts (ppm) are given relative to concentrated under vacuum (40 Torr) and the residue was distilled
Me4Si (1H and 13C NMR) and 85% H3PO4 (31P NMR). Mass spec-
in high vacuum to give a yellow, paraffin-like product (2.297 g, 67%
tra were recorded with a Kratos MS890 spectrometer (EI), an yield). B.p. 165Ϫ170 °C (0.8 Torr, kugelrohr distillation). 1H NMR
was washed with DCM (2ϫ15 mL). The combined extracts were
3
3
MSVKh TOF spectrometer with ionization by Cf-252 fission frag-
ments (plasma desorption technique, PD), and a Micromass Plat-
(CDCl3): δ ϭ 0.95 (t, J ϭ 7.4 Hz, 3 H, CH2CH3), 1.15 (d, J ϭ
6.8 Hz, 3 H, CH3), 1.42 (m, 2 H, CH2), 1.91 (m, 1 H, CH), 2.05
form 1 mass spectrometer through an ‘‘Openlynx’’ system (APCI [m, 2 H, (CH2)2], 2.29[m, 2 H, (CH2)2], 3.00 (m, 1 H, CHN), 3.17
technique). Electrospray (ES) ionisation mass spectra were meas-
ured with a Micromass BioQ II-ZS mass spectrometer. Organomet-
allic compound solutions at 5Ϫ10 pmol/µL in THF or acetonitrile
(m, 1 H, CH2N), 3.22 (m, 1 H, CH2N), 3.78 (m, 1 H, CH2N), 3.94
(q, 1 H, CH2N), 4.03 (m, 2 H, CH2O), 4.27 (br. s, 1 H, OH).
C10H21NO (171.16): calcd. C 70.12, H 12.36, N 8.18; found C
were infused by syringe pump (Harvard Apparatus Model 11) at 5 69.86, H 12.12, N 7.98.
1372
Eur. J. Inorg. Chem. 2002, 1367Ϫ1376

Easily Accessible Chiral P, N -Bidentate Aryl Phosphites
FULL PAPER
Table 7. Crystallographic data for 4i, 5i and 5l
Compound
4i
5i
5l
Empirical formula
Formula mass
C32H41ClN2O4PRh
687.00
orthorhombic, P212121 orthorhombic, P212121 orthorhombic, Pbca
12.883(8)
13.746(6)
18.178(11)
3219(3)
4
C31H41Cl2N2O3PPd
697.93
C32H38Cl2FeNO3PPd·C6H6
826.86
Crystal system, space group
˚
a [A]
12.827(3)
14.333(3)
17.378(4)
3194.9(11)
4
1.451
8.32
13.826(6)
18.872(7)
27.296(9)
7122(5)
8
1.542
11.45
˚
b [A]
˚
c [A]
3
˚
V [A ]
Z
Dx [Mg mϪ3
]
1.417
7.01
µ [cmϪ1
]
Crystal form, colour
Crystal size [mm]
F(000)
Tmin, Tmax
θmax [°]
Completeness to θmax
prisms, yellow
0.4ϫ0.3ϫ0.25
1424
0.751, 0.839
29.00
prisms, yellow
0.5ϫ0.4ϫ0.35
1440
0.653, 0.747
29.06
needles, red
0.4ϫ0.15ϫ0.1
3392
0.629, 0.892
27.00
98.1
100
99.0
No. of measured, independent and observed reflections 31319, 8280, 4952
20604, 8545, 7637
0.0366
389
Ϫ0.03(2)
0.0909
0.0405
37362, 7719, 3187
0.0883
430
Rint
0.0961
417
0.00(4)
0.1321
0.0729
1.096
No. of parameters
Absolute structure parameter
wR2 for all data
R for observed data
S
0.0788
0.0494
0.750
0.686, Ϫ0.731
0.990
1.376, Ϫ1.198
Ϫ3
˚
∆ρmax, ∆ρmin [e A
]
1.191, Ϫ1.672
(2S,3S)-2-[4-(Dimethylamino)benzylideneamino]-3-methylpentan-1-
OH), 4.21 (s, 5 H, HFc), 4.23 (t, 1J ϭ 1.9 Hz, 2 H, HFc), 4.42 (t,
1
ol (2i): (S)-(ϩ)-Isoleucinol (1.17 g, 1ϫ10Ϫ2 mol) was dissolved in 30 1J ϭ 1.9 Hz, 2 H, HFc), 4.60 (m, 1 H, CHO), 4.67 (d, J ϭ 5.8 Hz,
mL of dichloromethane. 4-(Dimethylamino)benzaldehyde (1.49 g,
1ϫ10Ϫ2 mol), Na2SO4 (1 g) and 15 mL of dichloromethane were
added to this solution with stirring, and the mixture was heated
under reflux for 3 h. After the mixture had cooled to room temper-
ature, the Na2SO4 was filtered off and washed with dichlorome-
thane. The solvent was removed and the resulting residue was dis-
1 H, CHN), 7.18 (m, 1 H, HAr), 7.28 (m, 1 H, HAr), 7.43 (m, 1 H,
HAr), 7.49 (m, 1 H, HAr), 8.45 (s, 1 H, CHϭ). C20H19FeNO
(345.08): calcd. C 69.58, H 5.55, N 4.06; found C 69.31, H 5.29,
N 4.00.
(2S,3S)-2-(Ferrocenylideneamino)-3-methylpentan-1-ol (2m): This
compound was synthesized analogously to 2i, starting from (S)-
(ϩ)-isoleucinol (1.17 g, 1ϫ10Ϫ2 mol) and ferrocenecarboxaldehyde
tilled under vacuum. Yellow viscous oil, 1.564 g (63% yield). n2D0
ϭ
1.4411. B.p. 165Ϫ167 °C (0.8 Torr, kugelrohr distillation). 1H
1
(2.14 g, 1ϫ10Ϫ2 mol). Orange solid, 2.685 g (81% yield). H NMR
3
NMR (CDCl3): δ ϭ 0.83 (t, J ϭ 7.6 Hz, 3 H, CH2CH3), 0.92 (d,
3
3
(CDCl3): δ ϭ 0.88 (t, J ϭ 7.2 Hz, 3 H, CH2CH3), 0.94 (d, J ϭ
6.8 Hz, 3 H, CH3), 1.24 (m, 2 H, CH2), 1.65 (m, 1 H, CH), 2.94
(m, 1 H, CHN), 3.82 (m, 2 H, CH2O), 3.99 (1 H, s, br, OH), 4.10
(s, 5 H, HCp), 4.34 (m, 1 H, HFc), 4.37 (m, 1 H, HFc), 4.51 (m, 1
H, HFc), 4.72 (m, 1 H, HFc), 8.06 (s, 1 H, CHϭ). 13C NMR
(CDCl3): δ ϭ 10.8 (s, CH3), 15.3 (s, CH3), 25.7 (s, CH2), 36.0 (s,
CH), 63.8 (s, CH2O), 66.9, 68.7, 69.9, 70.2, 70.3, 80.0 (all CFc), 77.9
(s, CHN), 161.9 (s, CHϭ). C17H23FeNO (313.11): calcd. C 65.19,
H 7.40, N 4.47; found C 65.47, H 7.23, N 4.09.
3J ϭ 6.8 Hz, 3 H, CH3), 1.04 (m, 1 H, CH), 1.46 (m, 1 H, CH2),
1.69 (m, 1 H, CH2), 2.41 (br. s, 1 H, OH), 2.98 (m, 1 H, CHN),
3
3.00 [s, 6 H, N(CH3)2], 3.78 (m, 2 H, CH2O), 6.67 (d, J ϭ 8.8 Hz,
2 H, HAr), 7.57 (d, 3J ϭ 8.8 Hz, 2 H, HAr), 8.08 (s, 1 H, CHϭ).
13C NMR (CDCl3): δC ϭ 10.6 (s, CH3), 15.2 (s, CH3), 25.1 (s,
CH2), 36.2 (s, CH), 39.5 [s, N(CH3)2], 63.6 (s, CH2O), 76.6 (s,
CHN), 110.9Ϫ151.3 (s, CAr), 161.3 (s, CHϭ). C15H24N2O (248.19):
calcd. C 72.54, H 9.74, N 11.28; found C 72.36, H 9.84, N 11.15.
(2R)-2-(Ferrocenylidineamino)-3-(methylthio)propan-1-ol (2j): This
compound was synthesized analogously to 2i, starting from (R)-2-
amino-3-(methylthio)propan-1-ol (1.21 g, 1ϫ10Ϫ2 mol) and ferro-
cenecarboxaldehyde (2.14 g, 1ϫ10Ϫ2 mol). Orange-red solid,
Preparation of Ligands; General Technique: A solution of bis(2,6-
dimethylphenyl) chlorophosphite (0.832 g, 2.7ϫ10Ϫ3 mol) in ben-
zene (15 mL) was added dropwise to a stirred solution of the appro-
priate alcohol 2 (2.7ϫ10Ϫ3 mol) and Et3N (0.4 mL, 2.7ϫ10Ϫ3 mol)
in the same solvent (15 mL) at 0 °C. The reaction mixture was then
heated to boiling point, allowed to cool down, stirred for 1 h at 50
°C, allowed to cool to room temp. and filtered. The solvent was
removed under vacuum (40 Torr), and the residue was dissolved
in hexane (20 mL), filtered, concentrated and dried under vacuum
(1 Torr).
1
2.636 g (83% yield). H NMR(C6D6): δ ϭ 1.87 (s, 3 H, CH3), 2.62
(m, 2 H, CH2S), 2.85 (s, 1 H, OH), 3.24 (m, 1 H, CHN), 3.69 (m,
2 H, CH2O), 4.10 (m, 1 H, HFc), 4.12 (m, 1 H, HFc), 4.13 (s, 5 H,
HFc), 4.46 (m, 1 H, HFc), 4.80 (m, 1 H, HFc), 8.02 (s, 1 H, CHϭ).
C15H19FeNOS (317.05): calcd. C 56.79, H 6.04, N 4.42; found C
56.50, H 3.87, N 4.13.
(1R,2S)-1-(Ferrocenylideneamino)indan-2-ol (2k): This compound
was synthesized analogously to 2i, starting from (1R,2S)-(ϩ)-cis-1-
amino-2-indanol (1.49 g, 1ϫ10Ϫ2 mol) and ferrocenecarboxal-
dehyde (2.14 g, 1ϫ10Ϫ2 mol). Dark yellow solid, 85% yield
(1R,2S)-2-Dimethylamino-1-phenylpropyl Bis(2,6-dimethylphenyl)
Phosphite (3a): Colourless oil, 0.913 g (75% yield). 31P NMR
(CDCl3): δ ϭ 146.7. 13C NMR (CDCl3): δ ϭ 8.6 (s, CH3), 17.53,
(2.933 g) after recrystallisation from toluene/heptane (1:1) mixture. 17.59, 17.72, 17.78 [CH3(Ar)], 41.6 (s, NMe2), 65.3 (d, 3J ϭ 3.8 Hz,
1H NMR (CDCl3): δ ϭ 3.21 (m, 2 H, CH2O), 3.99 (br. s, 1 H,
CHN), 77.4 (d, J ϭ 13.3 Hz, CHO), 119.8Ϫ149.3 (CAr). MS (EI,
2
Eur. J. Inorg. Chem. 2002, 1367Ϫ1376
1373

A. V. Korostylev et al.
FULL PAPER
70 eV): m/z (%) ϭ 451 (1) [M]ϩ, 380 (5), 273 (15), 162 (67), 122 C30H39N2O3P (506.27): calcd. C 71.12, H 7.76, N 5.53; found C
(100). C27H34NO3P (415.22): calcd. C 71.82, H 7.59, N 3.10; found 71.41, H 8.05, N 5.77.
C 72.11, H 7.43, N 3.33.
(2S,3S)-2-[4-(Dimethylamino)benzylideneamino]-3-methylpentyl
Bis(2,6-dimethylphenyl) (2R,4S,5R)-(5-Vinylquinuclid-2-yl)methyl
Bis(2,6-dimethylphenyl) Phosphite (3i): Yellow oil, 1.165 g (83%
Phosphite (3b): Colourless oil, 0.841 g (71% yield). 31P NMR
yield). 31P NMR (CDCl3): δ ϭ 136.4. MS (EI, 70 eV): m/z (%) ϭ
(C6D6): δ ϭ 138.4. 13C NMR (C6D6): δ ϭ 17.96, 18.00, 18.02, 18.05
520 (1) [M]ϩ, 400 (81), 316 (28), 122 (100). C31H41N2O3P (520.29):
[all CH3(Ar)], 24.4 (s, CHCH2CH), 26.9 (s, CH2CH2CH), 28.0 (s,
calcd. C 71.51, H 7.94, N 5.38; found C 72.84, H 8.14, N 5.16.
CH2CHCH2), 40.2 (s, CHCHCHϭ), 48.0 (s, NCH2CH), 49.2
(NCH2CH2), 56.2 (d, 3J ϭ 3.4 Hz, CHN), 64.1 (d, 2J ϭ 5.2 Hz,
Bis(2,6-dimethylphenyl) (2R)-2-(Ferrocenylideneamino)-3-(methyl-
CH2O), 114.3 (s, CH2ϭ), 140.8 (s, CHϭ), 119.9Ϫ149.5 (CAr). MS
thio)propyl Phosphite (3j): Dark red oil, 1.193 g (75% yield). 31P
(EI, 70 eV): m/z (%) ϭ 439 (4) [M]ϩ, 318 (95), 273 (9), 166 (42),
NMR (C6D6): δ ϭ 135.9. 13C NMR (C6D6): δ ϭ 16.6 (s, SCH3),
150 (100). C26H34NO3P (439.22): calcd. C 71.05, H 7.80, N 3.19;
found C 69.85, H 7.52, N 3.40.
17.9 [s, CH3(Ar)], 18.0 [s, CH3(Ar)], 37.2 (s, CH2S), 65.2 (s, CH2O),
3
68.8, 69.3, 70.5, 70.6 (all CFc), 69.6 (s, CCp), 71.8 (d, J ϭ 3.4 Hz,
CHN), 80.9 [s, CFc(ipso)], 124.4Ϫ149.5 (s, CAr), 162.3 (s, CHϭ).
MS (EI, 70 eV): m/z (%) ϭ 589 (3) [M]ϩ, 542 (36), 468 (98), 300
(34), 122 (100). C31H36FeNO3PS (589.15): calcd. C 63.16, H 6.16,
N 2.38; found C 61.89, H 6.41, N 2.63.
Bis(2,6-dimethylphenyl) [(2S)-1-Methylpyrrolidin-2-yl]methyl Phos-
phite (3c): Colourless oil, 0.724 g (69% yield). 31P NMR (C6D6):
δ ϭ 137.3. 13C NMR (C6D6): δ ϭ 17.40 [s, CH3(Ar)]. 17.44 [s,
CH3(Ar)], 22.6 [s, (CH2)2], 28.4 [s, (CH2)2], 41.2 (s, NCH3), 57.2 (s,
CH2N), 64.0 (s, CHN), 65.1 (s, CH2O), 119.4Ϫ149.2 (CAr). MS
(EI, 70 eV): m/z (%): 387 (3) [M]ϩ, 289 (1), 273 (42), 122 (100).
C22H30NO3P (387.19): calcd. C 68.20, H 7.80, N 3.62; found C
68.51, H 8.07, N 3.44.
Bis(2,6-dimethylphenyl) (1R,2S)-1-(Ferrocenylideneamino)indan-2-yl
Phosphite (3k): Red oil, 1.197 g (72% yield). 31P NMR (C6D6): δ ϭ
138.2. 13C NMR (C6D6): δ ϭ 17.97, 18.02, 18.20, 18.26 [CH3(Ar)],
38.9 (s, CH2), 68.9, 69.6, 70.4, 70.5 (all CFc), 69.4 (s, CCp), 77.2 (d,
2J ϭ 3.4 Hz, CHO), 77.6 (s, CHN), 81.2 [s, CFc(ipso)], 120.2Ϫ153.3
(s, CAr), 160.9 (s, CHϭ). MS (EI, 70 eV): m/z (%) ϭ 617 (2) [M]ϩ,
496 (2), 328 (24), 273 (7), 122 (100). C36H36FeNO3P (617.18): calcd.
C 70.02, H 5.88, N 2.27; found C 69.79, H 6.14, N 2.55.
[(2S)-1-Benzylpyrrolidin-2-yl]methyl Bis(2,6-dimethylphenyl) Phos-
phite (3d): Colourless oil, 0.962 g (77% yield). 31P NMR (C6D6):
δ ϭ 136.6. 13C NMR (C6D6): δ ϭ 17.4 [s, CH3(Ar)], 17.6 [s,
CH3(Ar)], 22.7 [s, (CH2)2], 28.4 [s, (CH2)2], 54.4 (s, CH2Ph), 59.5
(s, CH2N), 63.5 (d, 3J ϭ 4.2 Hz, CHN), 65.4 (d, 2J ϭ 3.4 Hz,
CH2O), 119.7Ϫ 149.3 (CAr). MS (EI, 70 eV): m/z (%) ϭ 463 (1)
[M]ϩ, 372 (3), 342 (47), 273 (3), 122 (85), 91 (100). C28H34NO3P
(463.23): calcd. C 72.55, H 7.39, N 3.02; found C 72.81, H 7.01,
N 3.36.
Bis(2,6-dimethylphenyl) (2R)-2-(Ferrocenylideneamino)-3-methylbu-
tyl Phosphite (3l): Red oil, 1.233 g (80% yield). 31P NMR (CDCl3):
δ ϭ 135.1. MS (EI, 70 eV): m/z (%) ϭ 571 (2) [M]ϩ, 450 (76), 282
(28), 122 (100). C32H38FeNO3P (571.19): calcd. C 67.26, H 6.70, N
2.45; found C 67.04, H 6.87, N 2.74.
Bis(2,6-dimethylphenyl) (2S,3S)-3-Methyl-2-(pyrrolidin-1-yl)pentyl
Phosphite (3e): Colourless oil, 0.813 g (68% yield). 31P NMR
(CDCl3): δ ϭ 136.1. 13C NMR (C6D6): δ ϭ 12.2 (s, CH3). 14.6 (s,
CH3), 16.9, 17.3, 17.9, 18.1, [all CH3(Ar)], 23.5 [s, (CH2)2], 27.4 (s,
CH2), 36.2 (s, CH), 51.5 (s, CH2N), 65.3 (s, CH2O), 76.1 (s, CHN),
119.6Ϫ149.5 (CAr). MS (EI, 70 eV): m/z (%) ϭ 443 (1) [M]ϩ, 273
(38), 122 (100). C26H38NO3P (443.26): calcd. C 70.40, H 8.64, N
3.16; found C 72.66, H 8.94, N 3.38.
Bis(2,6-dimethylphenyl) (2S,3S)-2-(Ferrocenylideneamino)-3-methyl-
pentyl Phosphite (3m): Dark red oil, 1.343 g (85% yield). 31P NMR
(C6D6): δ ϭ 135.9. 13C NMR (C6D6): δ ϭ 10.6 (s, CH3). 15.3 (s,
CH3), 17.2 [s, CH3(Ar)], 17.23 [s, CH3(Ar)], 25.0 (s, CH2), 36.3 (s,
CH), 63.6 (s, CH2O), 68.0, 68.2, 69.78, 69.80 (all CFc), 68.6 (s, CCp),
76.0 (s, CHN), 80.0 [s, CFc(ipso)], 123.5Ϫ148.7 (CAr), 160.6 (s,
CHϭ). MS (APCI): m/z (%) ϭ 586 (100) [M ϩ H]ϩ, 464 (18), 314
(42), 122 (10). C33H40FeNO3P (585.21): C 67.70, H 6.89, N 2.39;
found C 67.96, H 6.62, N 2.74.
(2R)-2-(Dibenzylamino)-3-methylbutyl
Bis(2,6-dimethylphenyl)
Phosphite (3f): Colourless oil, 1.184 g (79% yield). 31P NMR
(C6D6): δ ϭ 136.9. 13C NMR (C6D6): δ ϭ 18.0 [s, CH3(Ar)], 18.1
[s, CH3(Ar)], 20.5 (s, CH3), 21.3 (s, CH3), 27.9 (s, CH), 55.0 (s,
CH2Ph), 60.1 (s, CH2O), 63.4 (d, 3J ϭ 4.0 Hz, CHN), 119.8Ϫ149.4
(CAr). MS (EI, 70 eV): m/z (%) ϭ 555 (3) [M]ϩ, 464 (13), 273 (40),
122 (100). C35H42NO3P (555.29): calcd. C 75.65, H 7.62, N 2.52;
found C 75.31, H 7.49, N 2.67.
Preparation of Complexes
Preparation of Rhodium Complexes 4b؊4f and 4j: Rhodium com-
plexes with ligands 3bϪ3h and 3j were synthesized for the NMR
and IR experiments as follows. A solution of L* (3.6ϫ10Ϫ4 mol)
in CHCl3 (1.5 mL) was added dropwise to a stirred solution of
[Rh(CO)2Cl]2 (1.8 ϫ 10Ϫ4 mol) in the same solvent (1.5 mL). A 1-
mL sample of the resulting solution was then transferred to an
NMR tube or IR cuvette and spectral experiments were carried
out.
Bis(2,6-dimethylphenyl) 2-({[(1R)-1-Phenylethyl]imino}methyl)-
phenyl Phosphite (3g): Green oil, 1.099 g (82% yield). 31P NMR
(C6D6): δ ϭ 139.9. 13C NMR (C6D6): δ ϭ 17.8 [s, CH3(Ar)]. 17.9
[s, CH3(Ar)], 25.4 (s, CH3), 70.4 (s, CHN), 120.6Ϫ152.0 (s, CAr ,
)
153.8 (s, CHϭ). MS (EI, 70 eV): m/z (%) ϭ 498 (2) [M ϩ H]ϩ, 376
(56), 408 (15), 273 (52), 105 (100). C31H32NO3P (497.21): calcd. C
74.83, H 6.48, N 2.82; found C 75.04, H 6.22, N 3.13.
General Technique for Rhodium Complexes 4a, 4i and 4k؊4m: A
solution of the appropriate ligand (3.6 ϫ 10Ϫ4 mol) in DCM
(20 mL) was added dropwise to a stirred solution of [Rh(CO)2Cl]2
(2R)-2-[4-(Dimethylamino)benzylideneamino]-3-methylbutyl Bis(2,6-
dimethylphenyl) Phosphite (3h): Colourless oil, 1.093 g (80% yield). (0.070 g, 1.8 ϫ 10Ϫ4 mol) in the same solvent (20 mL) at 20 °C.
31P NMR (C6D6): δ ϭ 136.8. 13C NMR (C6D6): δ ϭ 17.94 [s, The reaction mixture was stirred at 20 °C for 30 min. The excess
CH3(Ar)], 17.98 [s, CH3(Ar)], 18.5 (s, CH3), 20.1 (s, CH3), 30.7 (s, solvent was then removed under vacuum (40 Torr), and 10 mL of
CH), 40.0 [s, N(CH3)2], 65.1 (d, 2J ϭ 11.6 Hz, CH2O), 77.1 (d,
hexane was added to the residue. The obtained precipitate was sep-
3J ϭ 2.7 Hz, CHN), 111.8Ϫ152.1 (s, CAr), 161.2 (s, CHϭ). MS arated by centrifugation, washed with hexane (2 ϫ 10 mL) and
(EI, 70 eV): m/z (%) ϭ 506 (2) [M]ϩ, 316 (52), 217 (66), 122 (100).
dried under vacuum (2 Torr).
Eur. J. Inorg. Chem. 2002, 1367Ϫ1376
1374

Easily Accessible Chiral P, N -Bidentate Aryl Phosphites
FULL PAPER
[Rh(CO)Cl(3a-PʝN)] (4a): Yellow solid, 0.193 g (87% yield). IR
(KBr): ν(CO) 2017 cmϪ1. C28H34ClNO4PRh (617.10): calcd. C
54.43, H 5.55, N 2.27; found C 54.73, H 5.69, N 2.51.
3d5/2), 134.0 (P 2p), 198.4 (Cl 2p), 399.6 (N 1s), 708.7 (Fe 2p).
C36H45FeClNO3PPd (767.12): calcd. C 56.27, H 5.90, N 1.82;
found C 56.58, H 6.11, N 2.02.
[Rh(CO)Cl(3i-PʝN)] (4i): Yellow solid, 0.221 g (89% yield). IR
(KBr): ν(CO) 2008 cmϪ1. C32H41ClN2O4PRh (686.15): calcd. C
55.94, H 6.02, N 4.08; found C 56.28, H 5.74, N 4.39.
Catalytic Experiments
Palladium-Catalysed Alkylation of Ethyl 3-Penten-2-yl Carbonate
with Dimethyl Malonate: [Pd(allyl)Cl]2 (3.6 mg, 10Ϫ5 mol) and li-
gand 3 (2Ϫ4 ϫ 10Ϫ5 mol) were dissolved in the appropriate solvent
[Rh(CO)Cl(3k-PʝN)] (4k): Yellow-brown solid, 0.260 g (92% yield).
IR (KBr): ν(CO) 2010 cmϪ1. C37H36ClFeNO4PRh (783.05): calcd. and the mixture was stirred at room temp. for 20 min. Ethyl 3-
C 56.69, H 4.63, N 1.79; found C 56.93, H 4.31, N 2.10.
penten-2-yl carbonate (160 mg, 10Ϫ3 mol), dimethyl malonate
(132 mg, 1.5 ϫ 10Ϫ3 mol), BSA [N,O-bis(trimethylsilyl)acetamide]
(305 mg, 1.5 ϫ 10Ϫ3 mol) and KOAc (2.5 mg) were then added to
the catalyst solution, and the mixture was stirred at room temp. for
24 h. The reaction mixture was then poured into saturated aqueous
NH4Cl solution and extracted with ether (2ϫ50 mL). The com-
bined organic extracts were washed with aqueous NaHCO3 and
water, dried (Na2SO4), filtered and concentrated under vacuum.
Purification by flash chromatography (silica gel; petroleum ether/
EtOAc, 8:1) gave the allylic alkylation product as a colourless oil.
The (S) absolute configuration was ascribed to the product on the
basis of the (Ϫ) sign of its optical rotation.[28]
[Rh(CO)Cl(3l-PʝN)] (4l): Yellow-brown solid, 0.239 g (90% yield).
IR (KBr): ν(CO) 2008 cmϪ1. MS (EI, 70 eV): m/z (%) ϭ 702 (34)
[M Ϫ Cl]ϩ, 674 (5) [M Ϫ Cl Ϫ CO]ϩ, 282 (52), 122 (100). MS (ES):
m/z (%) ϭ 702 (55) [M Ϫ Cl]ϩ, 300 (100). C33H38ClFeNO4PRh
(737.06): calcd. C 53.72, H 5.19, N 1.90; found C 54.00, H 5.53,
N 2.26.
[Rh(CO)Cl(3m-PʝN)] (4m): Yellow-brown solid, 0.239 g (88%
yield). IR (KBr): ν(CO) 2010 cmϪ1. C34H40ClFeNO4PRh (751.08):
calcd. C 54.31, H 5.36, N 1.86; found C 54.64, H 5.37, N 2.08.
[Rh(CO)Cl(3f-PʝN)] (4f):
A solution of ligand 3f (0.200 g,
3.6ϫ10Ϫ4 mol) in DCM (10 mL) was added dropwise to a stirred
solution of [acacRh(CO)2] (0.093 g, 1.8 ϫ 10Ϫ4 mol) in the same
solvent (10 mL) at 20 °C. The reaction solution was stirred for
30 min at room temp. to form [acacRh(CO)(η1-PʝN)] complex. A
solution of [Rh(CO)2Cl]2 (0.070 g, 1.8 ϫ 10Ϫ4 mol) in DCM
(10 mL) was then added to this solution and, after the mixture had
stirred for 1 h, all the volatiles were evaporated under vacuum (40
Torr). Regenerated [acacRh(CO)2] was extracted from the residue
with hexane (4 ϫ 15 mL), and the final residue was dried under
vacuum (2 Torr) to give the desired product. Yellow solid, 0.222 g
(85% yield). IR (KBr): ν(CO) 2009 cmϪ1. C36H42ClNO4PRh
(721.16): calcd. C 59.88, H 5.86, N 1.94; found C 60.17, H 6.13,
N 2.34.
Palladium-Catalysed Sulfonylation of Methyl 3-Penten-2-yl Carbon-
ate with Sodium p-Toluenesulfinate: Ligand 3 (1.1Ϫ2.2 ϫ 10Ϫ5 mol)
was added to a solution of [Pd(allyl)Cl]2 (2 mg, 5.5 ϫ 10Ϫ6 mol) in
the corresponding solvent at room temp. After the mixture had
been stirred for 15 min, a solution of methyl 3-penten-2-yl carbon-
ate (72.1 mg, 5 ϫ 10Ϫ4 mol) in the appropriate solvent was added.
Stirring was continued for 15 min and a suspension of NaSO2p-Tol
(178 mg, 10Ϫ3 mol) in the appropriate solvent was added. After the
mixture had been stirred for 48 h, brine (10 mL) was added, and
the mixture was extracted with THF. The organic phase was dried
(MgSO4) and concentrated under vacuum. Purification by flash
chromatography (silica gel; hexane/EtOAc, 5:1) gave the product as
a colourless oil. The (R) absolute configuration was ascribed to the
product on the basis of the (Ϫ) sign of its optical rotation.[30]
General Technique for Palladium Complexes 5i and 5l: A solution
of the appropriate ligand (3i or 3l, 2 ϫ 10Ϫ4 mol) in DCM (15 mL)
was added dropwise to a stirred solution of [Pd(COD)Cl2] (0.057 g,
2 ϫ 10Ϫ4 mol) in the same solvent (15 mL) at room temp. After
the mixture had been stirred for 1 h, the excess solvent was removed
under vacuum (40 Torr) and 10 mL of ether was added to the res-
idue. The obtained precipitate was separated by centrifugation,
washed with ether (2 ϫ 10 mL) and dried under vacuum (2 Torr).
Supporting Information: Experimental technique and catalytic re-
sults for the rhodium-catalysed hydrosilylation of acetophenone
with diphenylsilane (see also footnote on the first page of this
article).
Acknowledgments
cis-[PdCl2(3i-PʝN)] (5i): Yellow solid, 0.126 g (91% yield).
C31H41Cl2N2O3PPd (696.13): calcd. C 53.35, H 5.92, N 4.01; found
C 53.62, H 6.22, N 3.87.
The authors gratefully acknowledge receiving quincoridine from
Büchler GmbH (Germany) and thank Dr. P. V. Petrovskii (Institute
of Organoelement Compounds, Moscow) for assistance in charac-
terising the products and Dr. V. Tsarev (Institute of Organoelement
Compounds, Moscow) for a generous gift of (R)-2-amino-3-
(methylthio)propan-1-ol. This work was partially supported by the
Russian Foundation for Basic Research (Grants No. 00-15-99341,
00-15-97427 and 99-03-32899) and the Deutscher Akademischer
Austauschdienst (Referat 325, PKZ A/01/20127).
cis-[PdCl2(3l-PʝN)] (5l): Yellow-brown solid, 0.135 g (90% yield).
C32H38FeCl2NO3PPd (747.04): calcd. C 51.33, H 5.12, N 1.87;
found C 51.65, H 4.91, N 1.98.
[Pd(allyl)(3m-PʝN)]؉Cl؊ (6): A solution of imino phosphite 3m
(0.234 g, 4 ϫ 10Ϫ4 mol) in DCM (20 mL) was added dropwise to
a stirred solution of [Pd(allyl)Cl]2 (0.073 g, 2 ϫ 10Ϫ4 mol) in the
same solvent (20 mL) at room temp. After the mixture had been
stirred for 1 h, the solvent was removed under vacuum, and the
residue was washed with hexane (2 ϫ 10 mL) and dried under va-
cuum (2 Torr). Yellow-brown solid, 0.288 g (94% yield). 13C NMR
(C6D6): δ ϭ 11.6 (s, CH3), 16.1 (s, CH3), 18.7 [s, CH3(Ar)], 18.8 [s,
CH3(Ar)], 25.1 (s, CH2), 36.5 (s, CH), 55.0 (s, CH2 [allyl, trans-N)],
67.0 (s, CH2O), 68.2, 69.6, 70.2, 72.8 (all CFc), 69.4 (s, CCp), 75.3
(s, CHN), 80.2 [s, CFc (ipso)], 81.4 (d, 2J ϭ 42.8 Hz, CH2 [allyl,
trans-P)], 125.3 [d, 2J ϭ 8.2 Hz, CH(allyl)], 118.1Ϫ149.2 (s, CAr),
168.7 (s, CHϭ). MS (PD): m/z (%) ϭ 767 (20) [M]ϩ, 732 (100) [M
Ϫ Cl]ϩ, 690 (46), 585 (52), 121 (21). XPS: Eb [eV] ϭ 338.2 (Pd
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[I01478]
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