Recent Advances in Computational Explorations of Pericyclic Reactions and Pericyclases

Title:

Recent Advances in Computational Explorations of Pericyclic Reactions and Pericyclases

Schedule:

Date: 26^th February (Monday)

Time: 5:30 - 6:30 pm (HKT)

Venue: Lecture Theatre P2, Chong Yuet Ming Physics Building

Speaker:

Prof. Kendall N. Houk

Distinguished Research Professor

Department of Chemistry and Biochemistry

University of California, Los Angeles

Abstract:

Our lab has recently focused on cycloaddition transition states for reactions of triene and tetraene cycloaddends. These higher order cycloadditions often involve ambimodal transition states that lead to two or more products. We have explored many of these with DFT and molecular dynamics. In part one of my talk, I will describe these results in detail. In part two, I will describe the exploration of a variety of pericyclic reactions, especially electrocyclizations. Woodward and Hoffmann outlined a strict set of rules about electrocyclizations: reactions involving 4n electrons are conrotatory, and 4n+2 are disrotatory. We have discovered that polar substituents can make these rules inoperative such that normal steric and torsional effects control stereoselectivity. Predictions are made of other reactions of this type. In part three, the role of pericyclic reactions in Nature is discussed. With Yi Tang, we have identified a class of enzymes known as “pericyclases.” Our recent computational studies on these enzyme-catalyzed pericyclic reactions, including the use of AlphaFold2 to generate models of enzyme active sites and explorations of reactions in enzymes will be described. 

- ALL ARE WELCOME -