Photochemical Boronate Rearrangement Enables the One-Pot Synthesis of 2,4-Difunctionalized 2 H -Chromenes

2H-Chromenes are privileged pharmaceutical scaffolds, yet their synthesis typically requires multistep sequences or harsh conditions. We report a one-pot, visible-light-mediated strategy that directly converts 2’-hydroxychalcones and organoboronic acids into diverse 2,4-disubstituted 2H-chromenes. This approach leverages a photochemical 1,3-boronate rearrangement to achieve highly regioselective 1,2-addition to the α,β-unsaturated ketone moiety of 2’-hydroxychalcones, effectively diverting from traditional 1,4-addition pathways. The method provides modular access to 40 examples, notably including the synthetically challenging 2-alkyl-4-aryl motif. Demonstrating broad functional group compatibility, the protocol was successfully implemented in a continuous-flow system, achieving an 85% reduction in reaction time and facilitating gram-scale synthesis.