Enantioselective reduction of prochiral ketones using a reagent prepared from lithium aluminium hydride, (+)threo-1,16-dibenzyloxy,7(R),8(R)-dihydroxy hexadecane and alcohol

摘要

Asymmetric reduction of prochiral ketones to optically active chiral secondary alcohols was achieved using a reagent prepared by modifying lithium aluminium hydride with a chiral auxiliary, (+)threo-1,16-dibenzyloxy,7,8-dihydroxy hexadecane and various additive alcohols. (+)threo-1,16-dibenzyloxy,7(R),8(R)-dihydroxy hexadecane was prepared from (+)threo-9(R),10(R),16-trihydroxy hexadecanoic acid. Alcohols such as CH3(CH2)(n)-OH of different chain length (n = 0-11) and (R)-hydnocarpic alcohol were used. Complex prepared from (+)threo-1,16-dibenzyloxy,7 (R),8(R)-dihydroxy hexadecane, LAH and (R)-hydnocarpic alcohol reduced acetophenone in moderate enantioselectivity (maximum of 70% ee). Various arylalkylketones were reduced with the same complex. [References: 15]