Photocatalyst-free light-mediated three-component alkoxy-, hydroxy-, and azidotrifluoromethylation of alkenes

Photoinduced radical-polar crossover (RPC) reactions generally rely on the use of an external photocatalyst to generate the corresponding radical and ionic species, selected according to the redox potentials of the involved species. Herein, we describe a multicomponent light-induced RPC reaction that does not require an exogenous photocatalyst, enabling the efficient synthesis of diverse 1,2-trifluoromethyl alkyl ethers, alcohols, and azides. This protocol allows for the bifunctionalization of alkenes under mild conditions using purple light and a thianthrenium salt as a trifluoromethylating agent. Mechanistic experiments confirmed the formation of a benzylic sulfonium intermediate that can participate in different nucleophilic substitution reactions, being an alternative photocatalyst-free method to the classical RPC. A photocatalyst-free method enables efficient alkene difunctionalization in CF3-rich organic environments using accessible starting materials. This protocol is applicable for the synthesis of alkoxy, hydroxy, and azido derivatives.