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Organocatalytic and Stereoselective [3 + 2] Cycloadditions of Azomethine Imines with α,β‐Unsaturated Aldehydes
Author(s) -
Chen Wei,
Yuan XiangHong,
Li Rui,
Du Wei,
Wu Yong,
Ding LiSheng,
Chen YingChun
Publication year - 2006
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/adsc.200606102
Subject(s) - chemistry , stereoselectivity , trifluoroacetic acid , catalysis , organic chemistry , organocatalysis , enantioselective synthesis
Bipyrazolidin‐3‐one derivatives are biologically significant compounds and their importance has increased in the past decades. In this paper, the first stereoselective [3 + 2] dipolar cycloadditions of azomethine imines with α,β‐unsaturated aldehydes catalyzed by readily available α,α‐diarylprolinol salts are reported, providing a facile route to the synthesis of various chiral bipyrazolidin‐3‐one derivatives under mild conditions. The organocatalyst 1 g with strongly electron‐withdrawing groups exhibited the best stereoselectivity ( exo:endo up to 98:2, for exo product up to 97 % ee ), in the combination with trifluoroacetic acid.