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Amino Acids, XI: (±)Pipecolic Acid Derivatives ‐ Part 1: The [4+2] Cycloaddition Pathway
Author(s) -
Herdeis Claus,
Engel Wolfram
Publication year - 1992
Publication title -
archiv der pharmazie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.468
H-Index - 61
eISSN - 1521-4184
pISSN - 0365-6233
DOI - 10.1002/ardp.19923250708
Subject(s) - pipecolic acid , chemistry , cycloaddition , piperidine , stereochemistry , ring (chemistry) , acceptor , amino acid , organic chemistry , catalysis , biochemistry , physics , condensed matter physics
[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 another group 4a) .