Mechanophotocatalysis: A Generalizable Approach to Solvent‐minimized Photocatalytic Reactions for Organic Synthesis

Abstract

This proof‐of‐concept study cements the viability and generality of mechanophotocatalysis, merging mechanochemistry and photocatalysis to enable solvent‐minimized photocatalytic reactions. We demonstrate the transmutation of four archetypal solution‐state photocatalysis reactions to a solvent‐minimized environment driven by the combined actions of milling, light, and photocatalysts. The chlorosulfonylation of alkenes and the pinacol coupling of aldehydes and ketones were conducted under solvent‐free conditions with competitive or superior efficiencies to their solution‐state analogues. Furthermore, decarboxylative alkylations are shown to function efficiently under solvent‐minimized conditions, while the photoinduced energy transfer promoted [2+2] cycloaddition of chalcone experiences a significant initial rate enhancement over its solution‐state variant. This work serves as a platform for future discoveries in an underexplored field: validating that solvent‐minimized photocatalysis is not only generalizable and competitive with solution‐state photocatalysis, but can also offer valuable advantages.