The chlorozinc enolate of ethyl-[(2,2,5,5-tetramethyl-1-aza-2,5-disila)cyclopentyl]-acetate was reacted with the ZnCl2 complex of N-benzylidene-2-phenylglycine methyl ester in THF at −70 °C. After removal of the protecting silyl moiety (3S, 4S, αR)-1-(methoxycarbonyl)(phenyl)methyl-3-amino-4-phenyl-2-azetidinone was obtained in 73% yield with >97% d.e.. By treatment with aqueous ammonia complete epimerization
使乙基[((2,2,5,5-四甲基-1-氮杂-2,5-二
硅基)环戊基]-
乙酸乙酯的
氯锌烯醇盐与N-亚苄基-2-
苯基甘氨酸甲酯的ZnCl 2络合物反应, THF在-70°C下。除去保护性甲
硅烷基部分(3S,4S,αR)-1-(甲氧基羰基)(苯基)甲基-3-
氨基-
4-苯基-2-氮杂环丁酮后,产率为73%,de> 97%。通过用
氨水处理,完成了在α位的完全差向异构化。从THF中结晶出(3S,4S,αS)对映异构体,并通过X-射线晶体学确定绝对构型。