Novel Fluorous Prolinol as a Pre‐Catalyst for Catalytic Asymmetic Borane Reduction of Various Ketones.

Abstract

Alcohols Q 0230Novel Fluorous Prolinol as a Pre-Catalyst for Catalytic Asymmetic Borane Reduction of Various Ketones. -The pretreatment of FPR with an equimolar amount of trimethyl borate affords an oxaborolidine that catalyzes efficiently the reduction of ketones by BH3·THF. The corresponding alcohols are obtained in good to excellent yields and with up to 93% enantioselectivity. The prolinol FPR is recovered without any fluorous solvents or silica gel by simple cooling the organic phase and filtration. -(GOUSHI, S.; FUNABIKI*, K.; OHTA, M.; HATANO, K.; MATSUI, M.; Tetrahedron 63 (2007) 19, 4061-4066; Dep. Mater. Sci. Technol., Fac. Eng., Gifu Univ., Yanagido, Gifu 501-11, Japan; Eng.) -Klein 33-067