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

Preparation of Chiral Bis-β-amino Alcohols and Their Application in the Enantioselective Catalytic Borane Reduction of Aromatic Ketones

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制备双手性噁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％。

Three new chiral bis - B - amino alcohols,1,2 - bis[R - 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 - bis[R - 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.