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