A new synthesis of (2S)-4-oxopipecolic acid by thermal rearrangement of enantiopure spirocyclopropaneisoxazolidine
作者:Fabrizio Machetti、Franca M. Cordero、Francesco De Sarlo、Antonio Guarna、Alberto Brandi
DOI:10.1016/0040-4039(96)00796-4
日期:1996.6
(2S)-4-oxo-pipecolic acid is reported. The synthetic route employs as a key step the diastereoselective cycloaddition of the N-glycosylnitrone 7 to methylenecyclopropane followed by thermal rearrangement of the spirocyclopropaneisoxazolidine 8a. Stereoselective reduction of the N-BOC methyl ester of 4-oxopipecolic acid by L-selectride® gives the protected cis-4-hydroxy-pipecolic acid 14.
报道了(2S)-4-氧代-哌酸的新颖合成。合成路线采用N-糖基硝基7的非对映选择性环加成至亚甲基环丙烷作为关键步骤,然后对螺环丙烷异恶唑烷8a进行热重排。由三仲丁基硼氢化锂立体选择性还原的4- oxopipecolic酸的N-BOC甲酯®给出受保护的顺式-4-羟基-六氢吡啶羧酸14。