Proton-Coupled Electron Transfer in the Reduction of Carbonyls by Samarium Diiodie-Water Complexes

TitleProton-Coupled Electron Transfer in the Reduction of Carbonyls by Samarium Diiodie-Water Complexes
Publication TypeJournal Article
Year of Publication2016
AuthorsChciuk T, Anderson WR, Flowers, II RA
JournalJournal of the American Chemical Society
Abstract

Reduction of carbonyls by SmI2 is significantly impacted by the presence of water, but the fundamental step(s) of initial transfer of a formal hydrogen atom from the SmI2−water reagent system to produce an intermediate radical is not fully understood. In this work, we provide evidence consistent with the reduction of carbonyls by SmI2−water proceeding through protoncoupled electron transfer (PCET). Combined rate and computational studies show that a model aldehyde and ketone are likely reduced through an asynchronous PCET, whereas reduction of a representative lactone occurs through a concerted PCET. In the latter case, concerted PCET is likely a consequence of significantly endergonic initial electron transfer.

DOI10.1021/jacs.6b05879