不对称氨羟化反应合成紫杉醇C_(13)片段

Asymmetric Aminohydroxylation Synthesis of Paclitaxel Side Chain Precursor

用反式肉桂酸异丙酯为原料,N-溴代苯甲酰胺为助氧化供氮试剂,分别在配体3、4存在下进行锇催化的不对称氨羟化反应,一步制得抗癌药紫杉醇的C13片段N-苯甲酰基-(2R,3S)-3-苯基异丝氨酸异丙酯,收率分别为41.2%和43.6%,对映体过量(ee)均为97%。

Isopropyl N-benzoyl-(2R,3S)-3-phenylisoserine, a side chain precursor of paclitaxel, was synthesized from isopropyl trans-cinnamate and N-bromobenzamide by osmium-catalyzed asymmetric aminohydroxylation reaction in the presence of new chiral ligands 3 or 4 in yields of 41.2% and 43.6%, respectively. The enantiomeric excess of both were 97%.