The first asymmetric reaction catalyzed by chiral spiroborated esters with an O3BN framework was reported. In the presence of 0.1 equivalent of (R,S)-1 or (S,S)-1, acetophenone was reduced by 0.6 equivalent of borane in THF at 0—5 ℃ for 2 h to give (R)-1-phenylethanol of up to 76% ee and 73% isolated yield. Influence of reaction con-ditions on the stereoselectivity of the reduction was investigated and a possible catalytic mechanism of the chiral spiroborated esters toward the reduction was also suggested.
