Enantioselective Hydrogenation of Unsaturated Alcohols

Enantioselective hydrogenation of unsaturated alcohols such as allylic and homoallylic alcohols was not very efficient until the discovery of the BINAP-Ru catalyst. With Ru(BINAP)(OAc)2 as the catalyst, geraniol and nerol are successfully hydrogenated to give (S)- or (R)-citronellol in near-quantitative yield and with 96-99% ee [3 c]. A substratexatalyst ratio (SCR) of up to 48 500 can be applied, and the other double bond at the C6 and C7 positions of the substrate is not reduced. A high hydrogen pressure is required to obtain high enantioselec- 

7 (a) Miyashita, A., Karino, H., Shima-mura, J., Chiba, T., Nagano, K., Nohira, H., Takaya, H. Chem. Lett. 1989, 1007  

8 Schmid, R., Cereghetti, M., Heiser, B., Schonholzer, P., Hansen, H.-J. Helv. Chim. Acta 1988, 71, 897. 

Tetrahedron Lett. 2002, 43, 2789 (b) de Paule, S.D., Jeulin, S., Rato-velomanana-Vidal, V., Genet, J.P., Champion, N., Dellis, P. Tetrahedron Lett. 

---