Asymmetric Catalytic Reduction of Ketones with Hypervalent Trialkoxysilanes

Synlett

Volumn 1997, Issue 10, 1997, Pages 1175-1178

  Schiffers, R ^a   Kagan, H B ^a  

^a UNIVERSITÉ PARIS SUD   (France)

Author keywords

[No Author keywords available]

Indexed keywords

EID: 0342302945     PISSN: 09365214     EISSN: None     Source Type: Journal    
DOI: 10.1055/s-1997-982     Document Type: Article

References (18)

1. For a recent general reference to the stereoselectivity of the reduction of carbonyl groups see: Brunner, H. "Formation of C-H Bonds by Reduction of Carbonyl Groups", Houben-Weyl 1996, E21, Vol. 7 of the Workbench Edition, p. 3945-4197. Eds.: Helmchen, G., Hoffmann, R. W., Mulzer, J., Schaumann, E., Thieme Verlag Stuttgart 1996.
2. Chuit, C.; Corriu, R. J. P.; Reye, C.; Young, C. J. Chem. Rev. 1993, 93, 1371-1448 and references quoted therein.
3. Corriu, R.J.; Guerin, C.; Henner, B.; Wang, Q. Organometallics 1991, 10, 2297-2303 and references quoted therein.
4. Kira, M.; Sato, K.; Sakurai, H. J. Org. Chem. 1987, 52, 948-949.
5. Hosomi, A.; Hayashida, H.; Kohra, S.; Tominage, Y. J. Chem. Soc., Chem. Commun. 1986, 1411-1412.
6. Kohra, S.; Hayashida, H.; Tominaga, Y.; Hosomi, A. Tetrahedron Lett., 1988, 29, 89-92.
7. a) Hosomi, A. Reviews on Heteroatom Chemistry 1992, Vol. 7, 214-228, Oae, S., Editor, MYU, Tokyo, Japan.
8. b) Hojo, M.; Fuji, A.; Murakami, C.; Aihara, M.; Hosomi, A. Tetrahedron Lett. 1995, 36, 571-574.
9. Cai, D.; Hughes, D. L.; Verhoeven, T. R.; Reider, P. J. Tetrahedron Lett. 1995, 36, 7991-7994.
10. Short, J. D.; Attenoux, S.; Berrisford, D. J. Tetrahedron Lett. 1997, 38, 2351-2354.
11. Sugimura, T.; Yamada, H.; Inoue, S.; Tai, A. Tetrahedron: Asymmetry 1997, 8, 649-655 and references quoted therein.
12. Cox, P. J.; Wang, W.; Snieckus, V. Tetrahedron Lett. 1992, 33, 2253-2256 and references quoted therein.
13. a) Green, J.; Woodward, S. Synlett 1995, 155-156.
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15. a) Matsukawa, S.; Mikami, K. Tetrahedron: Asymmetry 1997, 8, 815-816.
16. b) Matsukawa, S.; Mikami, K. Nature 1997, 385, 613-615.
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18. Typical experimental procedure (example: acetophenone): First we have to recall that triethoxysilane 1b and especially trimethoxysilane 1a are rather toxic compounds and therefore care should be taken. Both are commercially available (Aldrich) and can be handled without problems via syringe-technique. 43 mg (0.15 mmol, 5 mol%) of (R)-Binol 11a were dissolved in 30 mL of dry ether under argon. At room temperature 0.10 mL (≈ 0.15 mmol, ≈ 1.5 mol/L in hexane) n-butyl lithium were added slowly and the resulting suspension stirred for 10 min, cooled to 0°C, and then 1.0 mL (≈ 6 mmol, 2 eq.) TMEDA was added and again stirred for 10 min, then 0.40 mL (3 mmol, 1 eq., 95%) trimethoxysilane 1a were added, stirred 10 min and finally 0.35 mL (3 mmol, 1 eq.) acetophenone 3 were added and the reaction mixture kept at 0°C for 6h. The reaction was quenched by adding 20 mL of 0.1 mol/L sodium hydrogencarbonate solution and stirred vigorously for 30 min at room temperature, then transferred into a separatory funnel and extracted with ether (3 times 50 mL). The ether was removed without drying and the resulting crude product was purified by column chromatography on silica gel with pentane/ether (3:1) immediately after (longer standing of the crude product at this stage resulted in gel formation and more difficult workup and lower yields) to give 295 mg (2.41 mmol) (S)-phenethyl alcohol 6 as a colorless liquid (80.3 % yield based on acetophenone 3 - entry 1, Table 2). The ee for this example was 61% (hplc on a Daicel OD-H column, n-hexane/ i-PrOH 9:1, flow 0.5 mL/min, (R)-6: 11.9 min, (S)-6: 13.3 min, absolute configuration previously assigned by measurement of the optical rotation).