ORGN 761 |
| The aza-Baylis-Hillman reaction is the coupling of the α-position of activated alkenes with imines, catalyzed by tertiary amines or phosphines, to form densely functionalized products bearing nitrogen stereocenters. Herein, we report a novel synthetic application of thiourea-based organocatalysts for the asymmetric aza-Baylis-Hillman reaction of nitrobenzenesulfonyl imines and methyl acrylate. The enantioselectivities achieved under optimized conditions are unprecedented, most ranging from 91-99% ee. This report illustrates a new reaction-type for this growing class of organocatalysts. Further, we have isolated and fully characterized, for the first time, a key intermediate in the Baylis-Hillman reaction. Isolation of this intermediate firmly corroborates the proposed Baylis-Hillman mechanism, and also provides important mechanistic insight into this reaction, allowing us to suggest a unique overall reaction pathway different from the standard Baylis-Hillman reaction. Reaction optimization, substrate scope, mechanistic insight, and synthetic applications are presented.
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Asymmetric Reactions, Molecular Recognition, Self Assembly, Bioorganic Chemistry, Process R&D
8:00 PM-10:00 PM, Wednesday, 16 March 2005 Convention Center -- Hall D, Poster
Division of Organic Chemistry |
