一类新型的双β-氨基醇的合成及催化硼烷对芳酮的不对称还原反应

以L-半胱氨酸盐酸盐出发，经与二卤代烷偶联，成酯和格氏反应制得三种双手性β-氨基醇，1,2-双R-2-氨基-3-羟基-3,3-二苯基丙硫基]乙烷(4a)，1,3-双R-2-氨基-3-羟基-3,3-二苯基丙硫基]丙烷(4b)，1,4-双R-2-氨基-3-羟基-3,3-二苯基丙硫基]丁烷(4c)。将此类双手性β-氨基醇与硼烷在THF溶液中反应，in situ制备双手性恶唑硼烷催化硼烷对芳酮的不对称还原，产物苯乙醇的光学收率达72.8%、α-溴代苯乙醇的光学收率达91.4%。

Preparation of chiral bis-β-amino alcohols and their application in the enantioselective catalytic borane reduction of aromatic ketones

Three new chiral bis - B - amino alcohols,1,2 - bisR - 2 - amino - 3 - hydroxyl - 3, 3 - diphenyl propylthio] ethane (4a), 1, 3 - bis R- 2-amino - 3 - hydroxyl -3,3- diphenyl -propylthio]propane(4b) ,1,4 - bisR - 2 - amino - 3 - hydroxyl - 3,3 - diphenyl propylthio]butane (4c) ,were synthesized starting with L - cysteine. Their application in the enantioseletive catalytic bo-rane reduction of aromatic ketones were studied and the enantiomeric excess 72.8 % for acetophenone and 91.4 for a - bromo acetophenone have been gained.