Amino Acids, XI: (±)Pipecolic Acid Derivatives - Part 1: The [4+2] Cycloaddition Pathway
作者:Claus Herdeis、Wolfram Engel
DOI:10.1002/ardp.19923250708
日期:——
[4+2] Cycloadditions of various dienes 1 with the acceptor‐substituted imines 2 furnished the 4‐oxo‐piperidine‐2,2‐dicarboxylate derivatives 3, 5, 11, 12. All efforts to get the regio‐isomeric 5‐oxo‐derivatives (Scheme 2) by variation of the reaction conditions and substitution pattern of 1 and 2 resulted in differing amounts of ring‐open products 4, 6, 8, 10. This is in contradiction to results of
[4 + 2] 各种二烯 1 与受体取代亚胺 2 的环加成得到 4-氧代-哌啶-2,2-二羧酸衍生物 3, 5, 11, 12。所有努力获得区域-异构体 5-氧代- 衍生物(方案 2)通过改变反应条件和 1 和 2 的取代模式导致不同数量的开环产物 4、6、8、10。这与另一组 4a) 的结果相矛盾。