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Enantioselective Trifunctional Organocatalysts for Rate‐ Enhanced Aza‐Morita–Baylis–Hillman Reactions at Room Temperature
Author(s) -
Garnier JeanMarc,
Anstiss Christopher,
Liu Fei
Publication year - 2009
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.200800679
Subject(s) - chemistry , methyl vinyl ketone , brønsted–lowry acid–base theory , lewis acids and bases , enantioselective synthesis , organocatalysis , baylis–hillman reaction , imine , catalysis , organic chemistry , polymer chemistry , asymmetric induction , base (topology) , mathematical analysis , mathematics
AbstractA Brønsted acid‐activated trifunctional organocatalyst, based on the BINAP scaffold, was used for the first time to catalyze aza‐Morita‐Baylis–Hillman reactions between N ‐tosylimines and methyl vinyl ketone with fast reaction rates and good enantioselectivity at room temperature. This trifunctional catalyst, containing a Lewis base, a Brønsted base, and a Brønsted acid, required acid activation to confer its enantioselectivity and rate improvement for both electron‐rich and electron‐deficient imine substrates. The role of the amino Lewis base of 1a was investigated and found to be the activity switch in response to an acid additive. The counterion of the acid additive was found to influence not only the excess ratio but also the sense of asymmetric induction.