Premium
Another Aspect of the Reaction Behavior of Cyclopentadienones: 1,5‐Sigmatropic Rearrangement of the 1,4‐Addition Products of Amines
Author(s) -
Yamaguchi Koki,
Kai Chika,
Yoshitake Yasuyuki,
Harano Kazunobu
Publication year - 2004
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.200300521
Subject(s) - pericyclic reaction , chemistry , sigmatropic reaction , cope rearrangement , diazomethane , aniline , rearrangement reaction , enol , medicinal chemistry , stereochemistry , computational chemistry , organic chemistry , catalysis
Abstract Treatment of 2,5‐bis(methoxycarbonyl)‐3,4‐diphenylcyclopentadienone ( 1 ) with aniline ( 2a ) gave the stereoisomeric 2‐anilino‐2,5‐bis(methoxycarbonyl)‐3,4‐diphenylcyclopentenones ( cis ‐ and trans ‐4a ). 1 H NMR spectroscopic monitoring of the reaction indicates that both compounds are derived from the 1,5‐sigmatropic rearrangement of the 1,4‐addition products cis ‐ and trans ‐3a . The structure of 3a was established by the X‐ray analysis of the product after methylation ( 3a ‐ Enol‐Me ) with diazomethane. The sequential pericyclic reaction behavior of 1 with amines is discussed on the basis of X‐ray crystal structures and the optimized structure of the transition state at the B3LYP/6−31G(d) level of theory. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)