Enabling Predictive Catalyst and Reaction Design in Asymmetric Organocatalysis (Invited)
- Type: Conference Presentation
- Conference Type:
AIChE Annual Meeting
- Presentation Date:
October 30, 2012
- Skill Level:
Our goal is to enable predictive catalyst and reaction design by developing experimental kinetic and spectroscopic protocols to probe complex reaction pathways. Investigations to date have relied primarily on empirical optimization based on simple analysis of final reaction product outcomes, which may neglect the importance of reaction dynamics and the interplay between stability and reactivity of intermediates in competitive networks. The temporal monitoring of reaction and selectivity profiles combined with spectroscopic identification of dynamic intermediate species is an underutilized approach in organocatalysis. Its development will aid in the delineation, rationalization, and exploitation of unexpected modes of stereocontrol. In this work we explore the generality of a proposed Curtin-Hammett paradigm for different classes of organocatalysts, applying comprehensive kinetic and spectroscopic protocols to a series of key transformations in pyrrolidine-based organocatalytic systems involving enamine intermediates. The central theme is the incorporation of our pioneering approach to quantitative kinetic analysis into a range of mechanistic tools. Kinetic-assisted mechanistic analysis will be developed as an orthogonal tool for discovery and optimization by rational design based careful documentation of reactivity patterns. This approach will address unexplained features of existing reactions as well as enable design of new catalyst/substrate combinations for high efficiency and selectivity, including complex reaction networks with multiple sequential transformations that begin to resemble metabolic systems, whence the inspiration for organocatalysis originates.