.alpha.-(Arylsulfonamido)borneols as auxiliaries in asymmetric synthesis: an efficient and highly stereoselective method for the reduction of .alpha.-keto esters
作者:Yi Bin Xiang、Ken Snow、Michel Belley
DOI:10.1021/jo00057a004
日期:1993.2
A method for preparation of enantiomerically pure alpha-hydroxy esters by stereoselective reduction of chiral alpha-keto esters under convenient conditions (LiAlH(OCEt3)3, THF,0-degrees-C) has been developed. The compounds exo,exo-3-(arylsulfonamido)-2-borneol and exo,exo-2-(arylsulfonamido)-3-borneol have been used as novel auxiliaries to achieve highly diastereoselective reductions. The auxiliaries can be removed by mild saponification (LiOH, THF-H2O, rt) without racemization of the reduced products.