Radical Hydro-Fluorosulfonylation of Propargylic Alcohols via Electron Donor–Acceptor Photoactivation

Abstract

A radical hydro-fluorosulfonylation of propargyl alcohols with FSO 2 Cl is presented based on the photoactivation of the electron donor−acceptor (EDA) complex. The reaction avoids the requirement for photocatalysts, bases, hydrogen donor reagents, any other additives, and harsh conditions, enabling the facile synthesis of various functionalized γ-hydroxy (E)alkenylsulfonyl fluorides. These multifunctional sulfonyl fluorides can be further diversified, providing access to various privileged molecules of biological relevance.

Radical Ring-Opening Fluorosulfonylation of Methylenecyclobutanols via Electron Donor–Acceptor Photoactivation

“…On the basis of the above studies and previous reports, , a plausible mechanism for this ring-opening fluorosulfonylation is proposed in Scheme D. To begin with, the interaction between methylenecycylobutanol 1 and FSO 2 Cl in diethyl ether produces EDA complex I .…”

“…Recently, we have shown that strong electrophilic sulfuryl chlorofluoride (FSO 2 Cl) displays significantly different reactivity from alkyl or aryl sulfonyl chlorides . It can readily form EDA complexes with weak electron donors, propargyl alcohols, to trigger the FSO 2 radical formation . Inspired by the radical-mediated C–C bond cleavage of cyclobutanols, , we hypothesized that the FSO 2 radical would induce a similar transformation to offer a new strategy for the synthesis of multifunctional sulfonyl fluorides.…”

Fluorosulfonyl Arylation of Alkynes via Electron Donor–Acceptor Photoactivation

“…We have recently shown that the fluorosulfonyl radical (FSO 2 •) can be generated via electron donor–acceptor (EDA) photoactivation . Building on these findings and drawing inspiration from radical fluorosulfonylation using sulfuryl chlorofluoride (FSO 2 Cl), we report a FSO 2 radical-mediated C–H cyclization of arenynes through visible light-activated EDA complexes for the synthesis of benzo-fused carbocycles and heterocycles (Scheme D).…”

“…On the basis of the results presented above and related reports, − , we proposed a plausible reaction mechanism (Scheme C). The reaction proceeds through the excitation of EDA complex I , forming the FSO 2 radical and radical cation II .…”