350
H. Brunner, D. Mijolo6ic / Journal of Organometallic Chemistry 577 (1999) 346–350
Table 3
Enantioselective hydrosilylation of acetophenone with diphenylsilane in the temperature range from 0°C to room temperature without solvent in
b
an argon atmosphere
No.
Procatalyst or cata- Ligand/coli-
Reaction time
(h)
Conversiona (%) Amount of silylenol ethera ee (Configuration) Runs
lyst
gand
(%)
(%)
7
8
9
1
1
6
1
2
2/5
–
22
22
20
–
89/94
97/97
94/96
–
0/0
0/0
0/0
–
26.4/26.9 R-(+)
25.1/26.6 R-(+)
28.2/29.4 R-(+)
30 R-(+)
2
2
2
–
10[19]
2
a
Complete conversion of diphenylsilane. Conversion, yield of acetophenone. No silylenol ether was formed.
Ratio catalyst:substrate 1:200, ratio [Rh]:ligand:substrate 1:1.1:200, ratio [Rh]:ligand:coligand:substrate 1:1.1:1.1:200.
b
Table 4
Enantioselective isomerization of 2-n-butyl-4,7-dihydro-1,3-dioxepin with NaBH4 at room temperature in THF/methanol 2:1a
No.
Catalyst or procata- Ligand Reaction time
Conversion (%)
Degree of isomerizaton
(%)
e.e. (Optical rotation) (%) Runs
lyst
(h)
1
1
1
6
1
–
2
24
24
\99
\99
\99
\85
10.2/11.5 (+)
12 (+)
2
–
2[20]
a
Ratio catalyst:NaBH :substrate 1:26:200, ratio [Rh]:ligand:NaBH :substrate 1:4:26:200.
4
4
[
[
8] H.D. Kaesz, R.B. Saillant, Chem. Rev. 72 (1972) 271.
followed by the main product 6 as a green band and a
by-product as a red band. Deep green crystals were
obtained from acetone. Yield 0.59 g (55%), m.p. 150°C
9] J.M. Brown, P.A. Chaloner, J. Chem. Soc. Perkin Trans. 2
1982) 711.
(
[
[
10] P.A. Chaloner, J. Organomet. Chem. 266 (1984) 191.
11] C.R. Landis, J. Halpern, J. Am. Chem. Soc. 109 (1987) 1746.
(
dec.).
Anal.
Found:
C,
46.83;
H,
4.21.
C H F O P RhW (1062.5). Calc.: C, 46.35; H, 4.17.
IR (KBr, cm ): 3090w (arom. C–H, Cp), 3020w
4
1
44
6
2
3
[12] J.A. Ramsden, T.D.W. Claridge, J.M. Brown, J. Chem. Soc.
Chem. Commun. (1995) 2469.
−
1
[
[
13] B.R. James, D. Mahajan, J. Organomet. Chem. 279 (1985) 31.
14] I. Ojima, T. Kogure, T. Terasaki, K. Achiwa, J. Org. Chem. 43
(
(
8
arom. C–H, Ph), 2950, 2890w (aliph. C–H), 1625m
vbr) (bridging Rh–H–W), 1410w (arom. CꢀC, Cp),
(
1978) 3444.
1
10vs (P–F). H-NMR (acetone-d ): l 7.08–8.07 (m,
6
[
15] A. Roucoux, M. Derocelle, J.-F. Carpentier, F. Agbossou, A.
Mortreux, Synlett (1995) 358.
2
0H, Ph–H), 5.20 (brs, 10H, cp–H), 3.65 (m, 2H,
diop
diop
diop
CH ), 2.86 (m, 2H, CH ), 2.69 (m, 2H, CH ),
1
Hz, J( P, H)=10.0 Hz, J( W, H)=107.3 Hz, 2H,
2
2
[16] H. Brunner, G. Riepl, H. Weitzer, Angew. Chem. 95 (1983)
326; Angew. Chem. Int. Ed. Engl. 22 (1983) 331.
diop
3
1
103
1
.14 (s, 6H, CH ), −17.99 (dt, J( Rh, H)=29.1
2
31
1
1
183
1
[
17] H. Brunner, A. K u¨ rzinger, J. Organomet. Chem. 346 (1988)
413.
3
1
1
Rh–H–W). P{ H}-NMR (acetone-d ): l 32.4 (d,
6
1
1
103
31
[18] H. Brunner, H. Nishiyama, K. Itoh, in: I. Ojima (Ed.), Cata-
lytic Asymmetric Synthesis, VCH, New York, 1993, p. 303.
[19] I. Ojima, K. Yamamoto, K. Kumada, in: R. Ugo (Ed.), As-
pects of Homogeneous Catalysis, D. Reidel, Boston, 1977, 3, p.
J( Rh, P)=158.6 Hz, 2P, Rh–P), −142.6 (m,
J( F, P)=707.8 Hz, 1P, PF ).
19 31
6
2
01.
[
[
[
20] H. Frauenrath, T. Phillips, Angew. Chem. 98 (1986) 261;
Angew. Chem. Int. Ed. Engl. 25 (1986) 274.
21] G.L. Soloveichik, B.M. Bulychev, Russ. Chem. Rev. 52 (1983)
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[
(
(
.