Succesive treatment of chiral esters 1 with LiN(i-Pr)2/Me3SiCl and di(tert-butyl) azodicarboxylate/TiCl4/Ti(i-PrO)4 gave N,N′ -di[(tert-butoxy)carbonyl]hydrazino esters 9 which on deacylation, hydrogenolysis, transesterification, and acidic hydrolysis furnished (2S)-α-amino acids 6 in high enantiomeric purity with efficient recovery of the auxiliary alcohol 7.
手性酯的Succesive治疗1用的LiN(I-PR)2 / Me的3的SiCl和二(叔丁基)偶氮二
羧酸酯/的TiCl 4 / Ti的第(i-PRO)4得到Ñ,Ñ ' -二[(叔丁氧基)羰基]
肼基酸酯9经过脱酰,氢解,酯交换和酸性
水解作用后,以高对映体纯度提供(2 S)-
α-氨基酸6,并有效回收了辅助醇7。