Heathcock Seminar in Organic Chemistry: Demystifying the Soai Reaction

Seminar | April 24 | 11 a.m.-12 p.m. | 120 Latimer Hall

 Prof. Scott Denmark, Department of Chemistry, University of Illinois at Urbana-Champaign

 College of Chemistry

The autocatalytic, asymmetry-amplifying alkylation of pyrimidine-5-carbaldehydes with diisopropylzinc, crowned as the ‘Soai reaction’ occupies a venerable position in organic chemistry. Since its discovery, the reaction with its unique properties representing a fortuitous confluence of three phenomena in catalysis: autocatalysis, enantioselective catalysis and non-linear effects (asymmetric amplification) has stood as an outstanding challenge for mechanism elucidation. Pioneering work over the last two decades has contributed to the milestone achievement of a consensus tetrameric alkoxide catalyst structure, However this knowledge has not enabled the formulation of a compelling transition state hypothesis nor provided deeper insights into the structural contributions from various parts of the molecule that give rise to asymmetric autocatalysis and the substrate idiosyncrasies in the transformation. A holistic understanding of the Soai reaction remains an open challenge.
This lecture will describe the discovery of amplifying asymmetric autocatalysis in a closely related pyridine system, which enabled detailed kinetic and spectroscopic studies to elucidate the evolution of the active tetramer and reveal the alkyl transfer transition state. This study provides the first definitive experimental rationalization to understand the fundamental basis of the structural requirements of the Soai reaction. These results will serve as a platform for further studies and explorations in the fascinating area of asymmetric autocatalytic reactions.

 Light refreshments will be served at 10:50 at The Coffee Lab

 seminarcoordinator-cchem@berkeley.edu, 510-643-0572