Highly Stereocontrolled Construction of 3-Alkoxyazetidin-2-ones Using Ester Enolate-Imine Condensation
作者:Makoto Shimizu、Takenori Ishida、Tamotsu Fujisawa
DOI:10.1246/cl.1994.1403
日期:1994.8
5-dimethoxymethyl-2-methyl-1,3-dioxolane ring as a chiral auxiliary could be controlled by the enolate metals, the ester parts, and the alkoxy groups. Addition of the titanium enolate provided (3R,4S)-3-alkoxyazetidin-2-one exclusively, while the corresponding (3R,4R)-isomer was obtained predominantly by the condensation using the zinc enolate of t-butyl α-benzyloxy-, phenoxy-, or t-butoxyacetate with the chiral imine
α-烷氧基乙酸酯的烯醇化物与具有 (4S,5S)-4,5-二甲氧基甲基-2-甲基-1,3-二氧戊环作为手性助剂的手性亚胺的非对映选择性加成反应可以通过烯醇化物金属来控制,酯部分和烷氧基。添加钛烯醇化物仅提供 (3R,4S)-3-alkoxyazetidin-2-one,而相应的 (3R,4R)-异构体主要通过使用叔丁基 α-苄氧基-的烯醇锌缩合获得,苯氧基-或叔丁氧基乙酸酯与手性亚胺。