A practical fluorosulfonylating platform via photocatalytic imidazolium-based SO<sub>2</sub>F radical reagent.

Zhang, Weigang; Li, Heyin; Li, Xiaojuan; Zou, Zhenlei; Huang, Mengjun; Liu, Jiyang; Wang, Xiaochen; Ni, Shengyang et al. · Nat Commun · 2022

basic_science · Level V

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Abstract

Sulfonyl fluorides are key components in the fields of chemical biology, materials science and drug discovery. In this line, the highly active SO<sub>2</sub>F radical has been employed for the construction of sulfonyl fluorides, but the utilization of gaseous ClSO<sub>2</sub>F as radical precursor is limited due to the tedious and hazardous preparation. Meanwhile, the synthesis of sulfonyl fluorides from inert SO<sub>2</sub>F<sub>2</sub> gas through a fluorosulfonyl radical (·SO<sub>2</sub>F) process has met with inevitable difficulties due to the high homolytic bond dissociation energy of the S(VI)-F bond. Here we report a radical fluorosulfonylation strategy for the stereoselective synthesis of alkenyl sulfonyl fluorides and functional alkyl sulfonyl fluorides with an air-stable crystalline benzimidazolium fluorosulfonate cationic salt reagent. This bench-stable redox-active reagent offers a useful and operational protocol for the radical fluorosulfonylation of unsaturated hydrocarbons with good yield and high stereoselectivity, which can be further transformed into valuable functional SO<sub>2</sub>F moieties.