Rhodium complexes with a new chiral amino-phosphinite ligand and their behavior as pre-catalysts in the hydroformylation of styrene

Article abstract of DOI:10.1016/j.inoche.2009.11.001

The new amino-phosphinite chiral ligand (S_a)-4-((S)-1-(diphenylphosphinooxy)-3-methylbutan-2-yl)-4,5- dihydro-3H-dinaphtho[2,1-c:1′,2′-e]azepine (1) has been synthesized and the corresponding more stable oxide has been characterized by X-ray an

Full text of DOI:10.1016/j.inoche.2009.11.001

Inorganic Chemistry Communications 13 (2010) 215–219
Contents lists available at ScienceDirect
Inorganic Chemistry Communications
journal homepage: www.elsevier.com/locate/inoche
Rhodium complexes with a new chiral amino-phosphinite ligand and their
behavior as pre-catalysts in the hydroformylation of styrene
*
G. Brancatelli , D. Drommi, G. Bruno, F. Faraone
Dipartimento di Chimica Inorganica, Chimica Analitica, Chimica Fisica dell’Università di Messina, Salita Sperone 31, Vill. S. Agata, 98166 Messina, Italy
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 15 June 2009
Accepted 6 November 2009
Available online 17 November 2009
The new amino-phosphinite chiral ligand (S )-4-((S)-1-(diphenylphosphinooxy)-3-methylbutan-2-yl)-
a
0
0
4
,5-dihydro-3H-dinaphtho[2,1-c:1 ,2 -e]azepine (1) has been synthesized and the corresponding more
stable oxide has been characterized by X-ray analysis. The ligand behavior in styrene hydroformylation
using [Rh(acac)(CO) ] and [Rh(COD) ]BF as precursors has been studied. With both pre-catalysts,
2
2
4
branched aldehyde 2-phenylpropanal was obtained in mild catalysis conditions with high yield and reg-
ioselectivity but as racemic mixture, indicating the loss of the ligand (1) during catalytic run. To support
Keywords:
Chiral amino-phosphinite
Hemilabile ligand
Catalysis
Hydroformylation
X-ray structural determination
these results, the reactions of [Rh(acac)(CO)
and the pre-catalysts behavior under CO/H
2
] and [Rh(COD)
has been investigated.
Ó 2009 Elsevier B.V. All rights reserved.
2 4
]BF with the ligand 1 have been performed
2
Complexes of d8 transition metals containing P,N-ligands have
been used in homogeneous catalytic processes and the bidentate
ligand coordination has been found to improve, in some cases,
the catalytic activity [1]. The presence of hard nitrogen and soft
phosphorus donor atoms gives to P,N-ligands peculiar features
which in some cases present advantages [2]. It has been found that
articles concerning the use of amino-phosphine ligands in the rho-
dium-catalyzed enantio-selective hydroformylation reaction, the
amino-monophosphinite ligands have been less studied [6].
a
The synthesis of the (S )-4-((S)-1-(diphenylphosphinooxy)-
0
0
3-methylbutan-2-yl)-4,5-dihydro-3H-dinaphtho[2,1-c:1 ,2 -e]aze-
pine (1) has been performed in two steps (Scheme 1) [7]: firstly
azepinic ring formed, by double nucleophilic substitution of (S)-
1
2
P,N-ligands can coordinate to metal centre via
j -P or j -P,N [3];
0
0
these coordination modes can change during reaction route, with
noteworthy involvements when the complex is used as pre-cata-
lyst. For example, the behavior of amino-phosphine as hemilabile
1-amino-3-methyl-butanol on (S
binaphthalene, refluxing for 24 h in toluene/acetonitrile mixture.
The diastereomer amino-alcohol (S )-2-((S)-3H-dinaphtho[2,1-
a
)-2,2 -bis(bromomethyl)-1,1 -
a
2
1
0
0
ligands, with change of coordination to metal from
j
-P,N to
j
-
c:1 ,2 -e]azepin-4(5H)-yl)-3-methylbutan-1-ol, (2), was obtained
P in the catalysis conditions, allows the dangling nitrogen atom
to act as ‘‘proton messenger” in the catalytic process [4]. Andrieu
et al. [5] examined the coordination properties of a variety of ami-
no-phosphine ligands in rhodium(I) complexes under variable CO
as white solid. In the subsequent step to a solution of compound
2 in toluene Et
at ꢀ10 °C. The reaction, monitored by P{ H} NMR, was concluded
after 1.5 h. The successive work-up afforded the (S )-4-((S)-
1-(diphenylphosphinooxy)-3-methylbutan-2-yl)-4,5-dihydro-3H-
3 2
N was added and successively ClPPh drop by drop
3
1
1
a
pressure, and reached the conclusion that
c
-P,N-ligands behave
1
0
0
as
lead in solution to an equilibrium between
cies; with some exception, in the examined rhodium-P,N com-
j
-P-a
-amino-phosphine, whereas the b-P,N amino-phosphines
dinaphtho[2,1-c:1 ,2 -e]azepine, 1, in high yields as white solid,
stable under argon atmosphere, but very susceptible to air-oxida-
tion in solution. The compound was characterized by elemental
2
1
j
-P,N and j -P spe-
1
31
1
plexes the ligand is
j
-P coordinated, under hydroformylation
analysis and NMR spectroscopy. In the P{ H} NMR spectrum in
conditions. To provide valuable insights into the behavior of chiral
P,N-ligands in the rhodium-catalyzed hydroformylation, we syn-
thesized a new amino-monophosphinite chiral ligand and used in
the styrene hydroformylation reaction the corresponding pre-cata-
6
C D
6
, compound 1 showed a singlet at 114.5 ppm and in the 1
H
NMR spectrum, in the same solvent, showed a pattern very similar
to that of starting amino-alcohol 2 except for a shift of the signals
and the lack of the OH resonance.
lysts derived from the [Rh(acac)(CO)
plexes, respectively. In contrast to the significant number of
2
] and [Rh(COD)
2
]BF
4
com-
With the aim of obtaining further structural information on
compound 1, we fully characterized by X-ray analysis the
corresponding oxidation product (S
a
)-2-((S)-3H-dinaphtho[2,1-
c:1 ,2 -e]azepin-4(5H)-yl)-3-methylbutyldiphenylphosphinate, (3),
Scheme 1) obtained by slow air-evaporation of CH Cl solution
of compound 1 [8].
0
0
(
2
2
*
Corresponding author. Fax: +39 90393756.
E-mail address: gbrancatelli@unime.it (G. Brancatelli).
1
387-7003/$ - see front matter Ó 2009 Elsevier B.V. All rights reserved.
doi:10.1016/j.inoche.2009.11.001

2
16
G. Brancatelli et al. / Inorganic Chemistry Communications 13 (2010) 215–219
Scheme 1.
Crystallographic structure of compound 3 is shown in Fig. 1 to-
gether with atomic numbering scheme [9]. Selected bond parame-
ters are given in the caption. The diastereomeric molecule 3
in which one N–C bond and the opposing C–C bond fused to one of
the naphthyl rings form the floor of the boat. The angle between
the mean planes through each of the naphthyl rings is 62.08(4)°;
the naphthyl moieties are not very planar: the deviation from pla-
narity results primarily from a small bend about the C(28)–C(21)
and C(29)–C(36) axes. Indeed the dihedral angle between mean
planes C(18)–C(19)–C(20)–C(21) and C(22)–C(23)–C(24)–C(25)–
C(26)–C(27) is 4.7(2)° and the one between mean planes C(29)–
C(36)–C(37)–C(38) and C(30)–C(31)–C(32)–C(33)–C(34)–C(35) is
6.4(1)°. The distortions of the naphthyl planes can be attributed
to the effect of ring strain in the seven-membered azepine cycle
crystallizes in the non-centrosymmetric space group P2
1 1 1
2 2 ,
exhibiting absolute configurations S and S for the anisotropic
a
binaphthoazepine group and C(14), respectively. The lone pair of
N(1) is turned away from oxygen: this conformation is stabilized
by weak intramolecular H-interactions C(17)–H(17A)ꢁ ꢁ ꢁN(1) and
C(39)–H(39A) ꢁ ꢁ ꢁO(1). The exo-oriented phenyl ring of –O
2 2
PPh
fragment is roughly perpendicular to naphthyl plane [dihedral an-
gle 79.1(5)°]. The azepine ring adopts a twisted-boat conformation
Fig. 1. Ortep view of compound 3 structure showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 30% probability level and H atoms are represented
by circles of arbitrary size. Selected bond lengths (Å) and angles (°) are: P(1)–O(1) 1.5934(2), P(1)–O(2) 1.485(2), P(1)–C(1) 1.807(2), P(1)–C(7) 1.799(2), O(1)–C(13) 1.465(2),
N(1)–C(14) 1.468(3), N(1)–C(18) 1.486(3), N(1)–C(39) 1.467(3), C(13)–C(14) 1.532(3), C(28)–C(29) 1.505(3)Å; O(2)–P(1)–O(1) 115.80(9), O(2)–P(1)–C(7) 114.6(1), O(1)–P(1)–
C(7) 100.30(9), O(2)–P(1)–C(1) 111.1(1), O(1)–P(1)–C(1) 106.88(9), C(7)–P(1)–C(1) 107.3(1), O(2)–P(1)–O(1) 115.80(9), C(13)–O(1)–P(1) 120.0(1), C(39)–N(1)–C(14) 116.8(2),
C(39)–N(1)–C(18) 114.2(2), C(14)–N(1)–C(18) 118.0(2)°. Selected torsion angle is: C(19)–C(28)–C(29)–C(38) 54.0(3)°. Selected hydrogen interactions are [Hꢁ ꢁ ꢁA (Å), Dꢁ ꢁ ꢁA (Å),
D–Hꢁ ꢁ ꢁA (°)]: C(17)–H(17A)ꢁ ꢁ ꢁN(1) 2.56, 2.934(3), 104; C(39)–H(39A)ꢁ ꢁ ꢁO(1) 2.63, 3.165(3), 115; C(21)–H(21)ꢁ ꢁ ꢁO(2)i 2.47, 3.323(3), 153; C(23)–H(23)ꢁ ꢁ ꢁO(2)i 2.61, 3.428(3),
1
48; (i) x + 1, y.

G. Brancatelli et al. / Inorganic Chemistry Communications 13 (2010) 215–219
217
fused with both naphthyl moieties, as reported for azepinium bro-
mide structures [10] and dinaphthazepines P,N-ligands [11]. As
commonly observed in structures containing diphenylphosphinate
groups [12], P(1) is a slightly distorted tetrahedron: bond angles
values indicate that electrostatic repulsion between the lone pair
of O(2) and bond pairs enlarges the angles involving O(2) and nar-
rows those at the tetrahedral basis. The bond length P(1)–O(2)
[
1.485(2) Å] is shorter than P(1)–O(1) [1.5934(2) Å], due to its
character of double bond, and is in the range for similar molecules
13]. Furthermore O(2) is involved in a weak bifurcated H-interac-
Scheme 3.
[
tion with C(21) and C(23), giving rise to molecular propagation
along a axis.
(d = 4.34, 4.26 ppm). The presence of the acetylacetonate ion coor-
dinated to rhodium centre was confirmed by a singlet for methine
–CH at d = 5.38 ppm and two singlets for methyl groups at d = 2.05
and 1.51 ppm, respectively. The solid IR spectrum of complex 4
The catalytic system was generated in situ by mixing [Rh(acac)-
(
2 2 4
CO) ] or [Rh(COD) ]BF and the chiral ligand 1 in a molar ratio 1:5,
in benzene or dichloromethane respectively. To the catalyst solu-
tion styrene was added, then the mixture was introduced in auto-
ꢀ
1
showed a m(CO) band at 1974 cm , indicating a CO ligand coordi-
clave under nitrogen stream and the gases CO and H
2
were
nated to rhodium(I). We tried to induce chelation of ligand 1
through N atom by refluxing a solution of compound 4 in toluene
for 48 h. In this conditions the oxidized product 3 was the only iso-
lated species.
admitted up at the desired pressure (Scheme 2) [14]. Several
experiments have been carried out in the temperature range be-
tween 303 and 333 K and pressure between 40 and 60 bar for a
period of 16 h. High chemo-selectivity was achieved with both
the pre-catalysts, indeed the ethyl-benzene was always less than
On standing for 1 h a benzene solution containing [Rh(acac)-
2 2
(CO) ] and ligand 1 (in twofold excess) under 1:1 CO/H pressure
1
%. Using the [Rh(acac)(CO)
not active at 318 K and 40 bar; increasing the temperature until
33 K and pressure up to 60 bar, a 100% conversion and a regiose-
2
] precursor, the catalytic system was
(40 bar) at 318 K, only the signals of compound 3 were detectable
by P{ H} and H NMR. It seems clear that under hydroformyla-
tion experimental conditions under CO/H pressure compound 4
2
3
1
1
1
3
lectivity value of 94:6 B/L in favor of the branched aldehyde 2-phe-
nylpropanal were observed, but the product was obtained as
released ligand 1 or did not even form it.
The lack of enantio-selectivity in rhodium-catalyzed hydrofor-
mylation of various olefins, when chiral ligands as amino-phos-
phines are used, is usually found [16]; the complete displacement
of the P,N-ligand from rhodium centre takes place regardless
of the nature of the ligand, under hydroformylation conditions.
Nevertheless rhodium-catalyzed styrene hydroformylations using
pre-catalysts with chiral P,N-ligands and affording the branched
aldehyde 2-phenylpropanal with discrete enantiomeric excesses
were already reported in literature [6a]. The obtained results sup-
port the formation in solution of an hydride-carbonyl species
racemic mixture.
A
similar trend was observed when
[
Rh(COD) ]BF was used as the catalytic precursor. In this case
2
4
the catalytic system was active at 318 K and 40 bar and in these
conditions a yield of 34% and a value of regioselectivity of 97:3
were found, but 2-phenylpropanal was obtained as racemic mix-
ture too.
The different conversion and B/L regioselectivity values ob-
2 2 4
tained at 318 K and 40 bar for [Rh(acac)(CO) ] and [Rh(COD) ]BF
pre-catalysts, indicate that the two catalytic species are different.
In order to gain informations about the catalytic systems, we
[Rh(H)(CO)
served [17].
We also performed the reaction of the [Rh(COD)
with ligand 1, using a molar ratio 1:1, in CH Cl [18]. To a turbid
orange solution of [Rh(COD) ]BF in CH Cl an equivalent amount
3
], under conditions in which catalytic activity is ob-
have performed the reactions of [Rh(acac)(CO)
Rh(COD) ]BF precursors with ligand 1 to explore the behavior
of the related products at experimental conditions of 40 bar of
CO/H pressure and 318 K, and in presence of CO at room temper-
2
]
and
[
2
4
2 4
]BF precursor
2
2
2
2
4
2
2
ature, respectively.
of ligand 1 was added. The mixture was stirred at room tempera-
ture for 2 h, concentrated and precipitated in hexane, giving a yel-
low solid.
We have conducted NMR studies in order to understand the nat-
ure of the species present in solution, dissolving the solid in mild po-
2
The reaction of [Rh(acac)(CO) ] with compound 1, in the molar
ratio 1:1, in toluene at room temperature afforded the compound
1
[
Rh(acac)(
j
-P-1)(CO)], 4, as a yellow solid (Scheme 3) [15]. It
was characterized by elemental analysis and IR and NMR spectros-
3
1
1
copy. The P{ H} NMR spectrum, in C
blet at d = 135.14 ppm (JRh–P = 192.4 Hz); in the H NMR spectrum,
in C solution, the signal shift of methylenic hydrogens of CH
6
D
6
solution, showed a dou-
lar solvents such as acetone-d
NMR spectra have clearly shown that from the reaction of
[Rh(COD) ]BF with ligand 1 a mixture of several products formed,
which chromatographic separation attempt failed owing to their
6 8
and THF-d by Schlenk techniques.
1
6
D
6
2
–
2
4
O–P fragment was very diagnostic of the coordination of ligand 1
via P atom. In fact, after the coordination of P atom, this signal re-
sulted shifted to higher frequency and splitted into two multiplets
3
1
1
instability. In particular the P{ H} NMR spectrum of the mixture
at room temperature, showed at least three broad doublets at
d = 124.9 ppm (JRh–P = 174 Hz), 121.5 ppm (JRh–P = 194 Hz) and
1
25.3 ppm (JRh–P = 168 Hz) together with the free ligand peak. The
assignment of these doublets was made difficult also by the instabil-
ity of these complexes. Our conclusion is that, as previously
observed in analogous P,N-rhodium systems [19], a dynamic equi-
librium was taking place between the monomeric rhodium chelate
2
2
(
j
-P,N) complex [Rh(COD)(
j
-1)]BF
-P-1)]BF , 6, coordinatively unsaturated
transient intermediate, formed in virtue of hemilabile ligand behav-
ior, and the dimer [Rh(COD)(1)] [BF , 7, having 1 as bridging li-
gands (Scheme 4). This reaction scheme was supported by P{ H}
NMR spectrum assignment: the doublet at d = 124.9 ppm (JRh–P
74 Hz) to the monomeric species 5, the doublet at d = 121.5 ppm
(JRh–P = 194 Hz) to the solvate species 6 and the doublet at
4
, 5, initially formed, the sol-
1
vate species [Rh(COD)(
j
4
2
4 2
]
31
1
=
1
Scheme 2.

2
18
G. Brancatelli et al. / Inorganic Chemistry Communications 13 (2010) 215–219
Scheme 4.
d = 125.3 ppm (JRh–P = 168 Hz) to the dimer species 7. By flushing
References
CO into the mixture solution the species further decomposed. As
[
1] (a) A. Pfaltz, Acc. Chem. Res. 26 (1993) 339–345;
b) I.D. Kostas, Curr. Org. Synth. 5 (3) (2008) 227–249.
2] J.W. Faller, K.H. Chao, H.H. Murray, Organometallics 3 (1984) 1231–1240.
for the hydroformylation reaction with the neutral [Rh(acac)(CO)
precursor, it is reasonable to suppose that an hydride-carbonyl
rhodium intermediate formed also with [Rh(COD) ]BF precursor,
2
]
(
[
2
4
[3] C.G. Arena, S. Calamia, F. Faraone, C. Graiff, A. Tiripicchio, J. Chem. Soc., Dalton
Trans. (2000) 3149–3157.
[
by COD displacement in hydroformylation experimental conditions,
leading to the branched aldehyde 2-phenylpropanal with high
chemo- and regioselectivity.
To conclude, the paper describes the synthesis and the behav-
ior in the rhodium-catalyzed styrene hydroformylation of the
pre-catalysts containing the new amino-monophosphinite chiral
4] (a) See for example: J. Andrieu, J.M. Camus, P. Richard, R. Poli, L. Gonsalvi, F.
Vizza, M. Peruzzini, Eur. J. Inorg. Chem. (2006) 51–61;
(b) G. Franciò, R. Scopelliti, C.G. Arena, G. Bruno, D. Drommi, F. Faraone,
Organometallics 17 (1998) 338–347.
[
5] (a) J. Andrieu, J.M. Camus, C. Balan, R. Poli, Eur. J. Inorg. Chem. (2006) 62–68;
(
1
b) J.M. Camus, J. Andrieu, P. Richard, R. Poli, Eur. J. Inorg. Chem. (2004) 1081–
091;
ligand (S
a
)-4-((S)-1-(diphenylphosphinooxy)-3-methylbutan-2-yl)-
(c) J.M. Camus, J. Andrieu, R. Poli, P. Richard, C. Baldoli, S. Maiorana, Inorg.
Chem. 42 (2003) 2384–2390;
0
0
4
,5-dihydro-3H-dinaphtho[2,1-c:1 ,-2 -e]azepine, 1, and reports
(
3
d) J. Andrieu, P. Richard, J.M. Camus, R. Poli, Inorg. Chem. 41 (2002) 3876–
885;
(e) J. Andrieu, J.M. Camus, J. Dietz, P. Richard, R. Poli, Inorg. Chem. 40 (2001)
597–1605;
f) J.M. Camus, D. Morales, J. Andrieu, P. Richard, R. Poli, P. Braunstein, F. Naud,
the crystal structure of the corresponding oxidation product, 3.
Although the conversion and the regioselectivity in favor of the
branched aldehyde are very high almost in every cases, the lack
of enantiomeric excess indicates that the rhodium catalysts con-
taining the ligand 1 are not efficient in the rhodium-catalyzed
styrene hydroformylation. This result is supported both by the
behavior of ligand 1 in the reactions with the [Rh(acac)(CO)
and [Rh(COD) ]BF precursors and by the one of the related prod-
ucts in the hydroformylation conditions. The results support the
presence of an hydride-carbonyl rhodium species as catalyst lead-
1
(
J. Chem. Soc., Dalton Trans. (2000) 2577–2585;
(g) J. Andrieu, J. Dietz, R. Poli, P. Richard, New J. Chem. 23 (1999) 581–583;
(
(
h) J. Andrieu, C. Baldoli, S. Maiorana, R. Poli, P. Richard, Eur. J. Org. Chem.
1999) 3095–3097.
2
]
[
[
6] (a) C.G. Arena, F. Nicolò, D. Drommi, G. Bruno, F. Faraone, J. Chem. Soc., Chem.
Commun. (1994) 2251–2252;
2
4
(b) I.D. Kostas, Inorg. Chim. Acta 355 (2003) 424–427.
0
0
7] Preparation
methylbutan-1-ol,
methylbutan-2-yl)-4,5-dihydro-3H-dinaphtho[2,1-c:1
of
(S
(2)
a
)-2-((S)-3H-dinaphtho[2,1-c:1 ,2 -e]azepin-4(5H)-yl)-3-
and (Sa)-4-((S)-1-(diphenylphosphinooxy)-3-
,2 -e]azepine, (1): to
)-2,2 -bis(bromomethyl)-1,1 -binaphthalene (1 g, 2.27 mmol),
N (95 l, 5.45 mmol) in toluene (25 ml), a solution of (S)-2-
amino-3-methylbutan-1-ol (1.1 eq.) in CH CN (20 ml) was added drop by drop.
The mixture was left to reflux at 90 °C for 24 h. Subsequently the solvent was
evaporated and the residue dissolved with 40 ml of CH Cl , washed with water
and brine. The organic phases were dried on MgSO and concentrated. By
ing to the intermediates [Rh(CO)
H) (C CH@CH )]BF
2
(H)
3
(C
6
H
5
CH@CH
2
)] and [Rh(CO)
3
-
0
0
a
0
0
(
2
H
6 5
2
4
.
solution of (S
containing Et
a
3
l
3
Acknowledgement
2
2
4
This work was supported by Ministero dell’Istruzione, dell’Uni-
versità e della Ricerca (MIUR-Rome; PRIN No. 2005035123).
adding hexane
a white solid was obtained and used without further
purification in the next reaction. 1H NMR (300 MHz, 3CDCl3) d: 7.98 (d,
3
3
J = 8.3 Hz, 2H, ArH), 7.96 (d, J = 7.9 Hz, 2H, ArH), 7.57 (d, J = 8.3 Hz, 2H, ArH),
3
7
.49 (dd, 3J = 6.7 Hz, 4J = 1.1 Hz, 2H, ArH), 7.46 (d, J = 6.5 Hz, 2H, ArH), 7.30–
Appendix A. Supplementary material
7.25 (m, 1H, ArH), 7.20 (d,
CH –N–CH ), 3.60 (m, 2H, CH
J = 6.7 Hz, 1H, CH –CH–CH ), 1.60 (b, 1H, OH), 0.88 (d, J = 6.7 Hz, 3H, CH
CH–CH –CH–CH ) ppm. Anal. Calcd. for C27 27NO
), 0.86 (d, 3J = 6.7 Hz, 3H, CH
381.21): C, 85.00; H, 7.13; N, 3.67. Found: C, 84.98; H, 7.10; N, 3.65.
Compound 1 was obtained by dissolving 400 mg (1.05 mmol) of 2 in a 50 ml
flask under Ar with 10 ml of toluene and subsequently adding 22
1.57 mmol) of triethylamine and 19 (1.05 mmol)
chlorodiphenylphosphine at ꢀ10 °C drop by drop. Immediately
3
J = 7.1 Hz, 1H, ArH), 3.69 (dd, AB,
2
J = 12.2 Hz, 4H,
2
2
2
–OH), 2.75 (m, N–CH–CH, 1H), 1.74 (sett,
3
3
3
3
3
–
CCDC 722593 contains the supplementary crystallographic data
for compound 3. These data can be obtained free of charge from
The Cambridge Crystallographic Data Centre via www.ccdc.cam.a-
c.uk/data_request/cif. Supplementary data associated with this
article can be found, in the online version, at doi:10.1016/
j.inoche.2009.11.001.
3
3
3
H
(
l
of
l
(
ll
a
white
precipitate formed. After 1.5 h filtration of the solid was carried out under

G. Brancatelli et al. / Inorganic Chemistry Communications 13 (2010) 215–219
219
argon atmosphere. The filtrate was concentrated and by adding hexane a white
magnetic stirrer. The reactions were carried out in a Teflon vessel fitted to the
internal wall of the autoclave, thus preventing undesirable effects due to the
metal of the reactor. The autoclave was closed and degassed through three
1
3
solid was obtained. H NMR (300 MHz, C
6
D
6
) d: 7.87 (d, J = 6.13 Hz, 4H, ArH),
3
3
7
.74 (d, 3J = 8.5 Hz, 2H, ArH), 7.58 (d, J = 8.2 Hz, 4H, ArH), 7.47 (t, J = 7.4 Hz,
3
3
1
H, ArH), 7.34 (t, J = 7.0 Hz, 1H, ArH), 7.1 (m, 10H, ArH), 4.09 (d, J = 8.0 Hz,
vacuum-nitrogen cycles.
[Rh(COD) ]BF and the ligand 1 in C
experiment 5 mmol of substrate, 0.01 mmol of complex and 0.04 mmol of
ligand), were introduced under nitrogen, and gases (CO/H 1:1) were admitted
A
solution consisting of [Rh(acac)(CO)
2
] or
3
3
2
H), 3.74 (s, 4H), 2.72 (m, 1H), 1.8 (sett, J = 7.0 Hz, 1H), 1.08 (d, J = 6.7 Hz, 3H,
2
4
6 6
H
(10 ml) and styrene (in a typical
31
1
CH
3
), 0.98 (d, 3J = 6.7, 3H, CH
3
)
ppm. P{ H} NMR (121 MHz,
6 6
C D ): d:
1
14.5 ppm. Anal. Calcd. for C39
H36NOP (565.25): C, 82.81; H, 6.41; N, 2.48.
2
Found: C, 82.78; H, 6.39; N, 2.46.
8] Preparation of (S )-2-((S)-3H-dinaphtho[2,1-c:1 ,2 -e]azepin-4(5H)-yl)-3-methyl-
butyldiphenylphosphinate, (3): compound was obtained by spontaneous
oxidation in the air of 1 in CH Cl solution. By slow evaporation of solvent
crystals suitable for X-ray analysis were obtained. H NMR (300 MHz, C
.87–7.72 (m, 12H), 7.4–7.27 (m, 10H), 4.51 (sb, 1H), 4.15 (sb, 1H), 3.44 (d AB,
up to the desired pressure. After 16 h the autoclave was cooled in a cold water
bath and slowly vented. A sample of the homogeneous reaction mixture was
then analyzed by gas chromatography.
0
0
[
a
3
1
*
2
2
[15] Preparation of [Rh(acac)(CO)(
j -P-P,N )], (4): to a brown solution of
1
6
D
6
) d:
[Rh(acac)(CO) ] (50 mg, 0.194 mmol) in toluene one eq. of ligand 1 was
2
7
added at room temperature. Immediately an effervescence was noted and the
solution became clear yellow. After 2 h the solution was concentrated and the
2
2
J = 12.1 Hz, 2H), 2.91 (d, AB, J = 12.1 Hz, 2H), 2.40 (m, 1H), 1.58 (sett., 1H),
31
1
0
.94 (d, 3J = 6.0 Hz, 6H) ppm. P{ H} NMR (121 MHz, C
Anal. Calcd. for C39 36NO P (581.25): C, 80.53; H, 6.24; N, 2.41. Found: C,
0.50; H, 6.19; N, 2.38.
9] Intensity data for compound 3 were collected on a Nonius/Bruker APEX II
kappa CCD diffractometer with area detector at 100 K, using grafite
monochromator and monochromatic radiation Mo K . Cell refinement and
6
D
6
): d: 29.93 ppm.
residue reprecipitated in hexane, giving a yellow solid in almost quantitative
1
) d: 7.90 (d, 3J = 7.7 Hz, 2H, ArH), 7.86 (d,
H
2
yield. H NMR (300 MHz, CDCl
3
3
J = 8.3 Hz, 2H, ArH), 7.56 (d, 3J = 8.3 Hz, 2H, ArH), 7.46 (d3, J = 8.5 Hz, 4H, ArH),
7.32–7.24 (m, 4H, ArH), 7.20–7.12 (m, 4H, ArH), 7.07 (dt, J = 7.4 Hz, 4J = 2.5 Hz,
2H, ArH), 6.92 (dt, 3J = 7.7 Hz, 4J = 2.6 Hz, 2H, ArH), 5.46 (s, 1H, CO–CH–CO),
3
8
[
a
2
a
4.34 (m, 1H, CH–CHH–OP), 4.26 (m, 1H, CH–CHH–OP), 3.7 (dd, AB, J = 12.3 Hz,
reduction were performed with DIRAX/LSQ and EVALCCD programs. The
structure was solved by Direct Methods, using Sir 2004 program and refined
with weighted full-matrix least-square procedure (based on F ) (SHELX-97). All
4H, CH
1H, CH
0.92 (d, J = 6.9 Hz, 3H, CH
2
–N–CH
2
), 2.76 (m, 1H, N–CH–CH
2
), 2.13 (s, 3H, CH
3
C@O), 1.78 (sett.,
C@O), 0.95 (d, J = 6.9 Hz, 3H, CH –CH–CH ),
) ppm. P{ H} NMR (121 MHz, CDCl ) d:
3
3
–CH–CH
3
), 1.60 (s, 3H, CH
3
3
3
2
3
31
1
3
–CH–CH
3
3
non-hydrogen atoms were refined with anisotropic thermal parameters.
Hydrogen atoms were placed in geometrically calculated positions and
refined using the riding model. Absolute configurations are in agreement
with the synthetic route; inversion of configuration did not give better results
135.14 (d, JRh–P = 192.4 Hz) ppm. m IR: 1974 (C„O), 1580 (C„O), 1561 (C„O)
ꢀ
1
cm
.
[16] (a) B. Breit, W. Seiche, Synthesis-Stuttgart 1 (2001) 1;
(b) F. Agbossou, J.F. Carpentier, A. Mortreux, Chem. Rev. 95 (1995) 2485–2506.
[17] D.P.W.N.M. vanLeeuwen, C. Claver, Rhodium Catalyzed Hydroformylation,
Kluwer Academic, 2000. pp. 17–25.
during structural refinement. Crystallographic data for 3: C39
M = 581.66 g/mol, colorless, long needle, 0.903 ꢂ 0.235 ꢂ 0.189 mm,
Orthorhombic, space group P2 a = 8.492(1) Å, b = 16.847(3) Å,
c = 21.744(3) Å, = b = = 90°, V = 3110.8(8) Å , Z = 4, Dc = 1.242 g/cm ,
mu = 0.124 mm , F(0 0 0) = 1232, S = 1.136, R = 0.0326, wR = 0.0674.
2
H36NO P (3):
1
1
2 2
1
,
[18] Reaction of [Rh(COD)
2
]BF
4
with 1: to a turbid orange solution of [Rh(COD)
2 4
]BF
3
3
a
1
c
(25 mg, 0.062 mmol) in 10 ml of CH
2
Cl one eq. of 1 was added (36 mg,
2
ꢀ
1
2
0.063 mmol) at room temperature. The reaction mixture was left to stirring for
[
[
[
10] M. Schneider, A. Linden, A. Rippert, Acta Cryst. C56 (2000) 1004–1006.
11] M. Widhalm, U. Nettekoven, K. Mereiter, Tetrahedron 10 (1999) 4369–4391.
12] G. Franciò, C.G. Arena, M. Panzalorto, G. Bruno, F. Faraone, Inorg. Chim. Acta
2 h. After this time the solution was concentrated ad the residue reprecipitated
in hexane, giving a yellow solid. 31P{ H} NMR (121 MHz, acetone-d
1
6
) d: 124.9
(d, JRh–P = 173.8 Hz), 125.3 (d, JRh–P = 168 Hz); 121.5 (d, JRh–P = 194 Hz) ppm.
[19] (a) R. Kadyrov, T. Freier, D. Heller, M. Michalik, R. Selke, J. Chem. Soc., Chem.
Commun. (1995) 1745–1746;
2
77 (1998) 119–126.
[
[
13] (a) I.D. Grice, I.D. Jenkins, W.K. Busfield, K.A. Byriel, C.H.L. Kennard, Acta Cryst.
E60 (2004) o2384–o2385;
(b) J.H. Nelson, Coordinat. Chem. Rev. 139 (1995) 245–280;
(c) N. Shinkawa, A. Sato, J. Shinya, Y. Nakamura, S. Okeya, Bull. Chem. Soc. Jpn.
68 (1995) 183–190.
(
b) Y.-C. Liu, C.-H. Lin, B.-T. Ko, Acta Cryst. E65 (2009) o2058.
14] Catalytic runs: all catalytic runs were performed in a 100 ml Berghoff stainless-
steel autoclave equipped with gas and liquid inlets, a heating device, and a