Enantiopure erythro- and threo-1-aryl-1-[2-pyrrolidyl]-methanols: synthesis from l-proline
作者:Arlette Solladié-Cavallo、Khalid Azyat、Michel Schmitt、Richard Welter
DOI:10.1016/j.tetasy.2005.01.010
日期:2005.3
Enantiopure (1R,2S)-erythro- and (1S,2S)-threo-isomers of four new aryl-pyrrolidyl alcohols 5aH, 5aMe, 5bH and 5bMe have been obtained in five steps from (−)-(S)-proline and fully characterized. The oxidation of alcohol 8 into aldehyde 9 was the most difficult step and racemization occurs during Swern oxidation but this difficulty can be overcome by using SO3/pyridine as oxidant. Diastereomer I of
对映体纯(1 - [R,2小号) -赤-和(1小号,2小号) -苏型的四个新的芳基吡咯烷基醇-异构体5AH,5aMe,5BH和5bMe( - ) - (已在五个步骤从获得的小号)-脯氨酸,并具有完整的特征。醇8氧化为醛9是最困难的步骤,在Swern氧化过程中发生了外消旋化,但是可以通过使用SO 3 /吡啶作为氧化剂来克服这一困难。受保护的氨基醇10a的非对映异构体I结晶并通过X射线晶体学显示为(1R,2S)-赤型异构体(e - 10a - I)。因此,(1 R,2 S)-赤型结构被分配给所有从e - 10a - I获得的化合物,结果,(1 S,2 S)-苏式结构被分配给非对映异构体II。