Hydrogen bonding mediated electron donor-acceptor acceptor catalysis in hydrosulfonylation and sulfonyl dehydrogenation of olefins.

Abstract

Electron donor-acceptor (EDA) acceptor catalysis remains significantly less developed than donor catalysis. Herein, a hydrogen-bond-mediated EDA acceptor catalysis using readily available 4,4'-di-tert-butyl-2,2'-bipyridine (dtbbpy) or 4-tert-butylpyridine as the acceptor catalyst is developed, enabling the hydrosulfonylation of unactivated olefins and sulfonyl dehydrogenation of styrenes, utilizing sodium sulfinates as the sulfonyl source. The reaction proceeds under mild conditions. A broad range of functional groups is well tolerated, affording good to excellent yields. Preliminary mechanistic investigations, including both computational studies and experiments, indicate that hydrogen bonding between sulfinic acid and the acceptor catalyst may facilitate the formation of a photoresponsive EDA complex and the subsequent photo-induced radical generation.