A Convenient Synthesis of Enantiomeric Pairs of 2,5-Disubstituted Pyrrolidines of C<sub>2</sub>-Symmetry
作者:Yukio Yamamoto、Jun'ichi Hoshino、Yukiko Fujimoto、Junko Ohmoto、Seiji Sawada
DOI:10.1055/s-1993-25852
日期:——
By the use of (-)-1-phenylethylamine as a chiral auxiliary, three diastereomeric isomers of 2,5-bis(methoxycarbonyl)pyrrolidine derivatives are prepared from dimethyl rac-2,5-dibromoadipate and separated by crystallization and chromatographic fractionation involving stereoselective hydrolysis. The cis isomer is recovered and epimerized to the trans counterparts. Starting from each of the two trans isomers, optically active 2,5-disubstituted [2,5-bis(methoxymethyl) and 2,5-bis(methoxymethoxymethyl)] pyrrolidines of C 2-symmetry are synthesized by a short route.
通过使用 (-)-1-苯基乙胺作为手性辅助剂,从二甲基阳离子-2,5-二溴己二酸酯制备了三种二叠体异构体的 2,5-双(甲氧基羧基)吡咯烷衍生物,并通过结晶和涉及立体选择性水解的色谱分离进行分离。收回顺式异构体并使其异构化为反式异构体。从每种反式异构体出发,通过一种简短的路线合成了具有 C2 对称性的光学活性 2,5-二取代的 [2,5-双(甲氧基甲基)和 2,5-双(甲氧基甲氧基甲基)] 吡咯烷。