Light-promoted photocatalyst-free and redoxneutral hydrosulfonylation of unactivated alkenes using sulfinic acid.

A hydrosulfonylation reaction of unactivated alkenes with sulfinic acids was realized under light irradiation. This reaction features photocatalyst- and additive-free conditions. A diverse set of unactivated alkenes can be transformed into alkyl-substituted sulfones with good yields and anti-Markovnikov regioselectivity. The present protocol was amenable to gram-scale synthesis, as well as late-stage modification of drugs and natural products. Preliminary mechanistic studies on UV-visible light absorption suggested the key role of sulfinic acid as a light-absorbing species. DFT calculations also shed light on the mechanism of this reaction, which may involve a radical chain pathway. [ABSTRACT FROM AUTHOR]