1. Catalytic Ketyl-Olefin Cyclizations Enabled by Proton-Coupled Electron Transfer

Kyle T. Tarantino, Peng Liu, Robert R. Knowles:

https://pubs.acs.org/doi/abs/10.1021/ja404342j

ABSTRACT: Concerted proton-coupled electron transfer is a key mechanism of substrate activation in biological redox catalysis. However, its applications in organic synthesis remain largely unexplored. Herein, we report the development of a new catalytic protocol for ketyl-olefin coupling and present evidence to support concerted proton-coupled electron transfer being the operative mechanism of ketyl formation. Notably, reaction outcomes were correctly predicted by a simple thermodynamic formalism relating the oxidation potentials and pK_a values of specific Brønsted acid/reductant combinations to their capacity to act jointly as a formal hydrogen atom donor.