Thiosulfonylation of Unactivated Alkenes with Visible-Light Organic Photocatalysis

A metal-free
method for the vicinal thiosulfonylation of unactivated
alkenes with thiosulfonates using 9-mesityl-10-methylacridinium perchlorate
as the photo-organocatalyst with visible-light irradiation has been
developed. The method can be performed in dimethyl carbonate under
air at room temperature and features a broad functional group compatibility.
Metrics indicate the green potential of the developed versus the state-of-the-art
methodologies. Mechanistic studies revealed no single electron transfer
but involvement of an energy transfer from the excited photo-organocatalyst
to thiosulfonate reactant, subsequently providing a sulfenyl and a
sulfonyl radical via homolytic cleavage.