Strategies towards Catalytic Olefin Dicarbofunctionalization

Seminar | November 21 | 11 a.m.-12 p.m. | 120 Latimer Hall

 Prof. Ramesh Giri, University of New Mexico

 College of Chemistry

Integration of cross-coupling, a reaction with unlimited depth and breadth of industrial and academic applications, into three-component and tandem reaction manifolds has the potential to create a methodology of unparalleled synthetic power. These reactions that generate two new carbon-carbon bonds in one synthetic step could find important applications in rapidly building molecular complexity from simple and readily available feedstock chemicals, and in making highly diversified carbo- and heterocycles. However, the development of these important methods has met with only limited success due primarily to complications by -hydride elimination from organotransition metal species that are generated as intermediates during reaction. In this talk, we will present our different strategies that enable Ni, Cu and Pd-catalysts to difunctionalize olefins with aryl halides and organometallic reagents/enolates in a wide variety of molecular backbones. The talk will mainly focus on our recent strategy of using heteroatom coordination to stabilize Heck organotransition metal intermediates in situ as transient metallacycles in order to suppress -H elimination, and promote transmetalation and reductive elimination to furnish desired products. The effectiveness of Cu, Ni and Pd-based catalysts for tandem cyclization/cross-coupling reactions of olefin-tethered alkyl halides as well as carbonyl compounds with aryl halides/organozinc reagents will also be showcased, which facilitate to generate a wide range of complex carbocycles and N,O-heterocycles relevant to the synthesis of lignan natural products. Mechanistic pathways pertaining to these new reactions will also be discussed.

 Light refreshments will be served at 10:50 at The Coffee Lab, 510-643-0572