Green Photo-Organocatalytic C-H Activation of Aldehydes: Selective Hydroacylation of Electron-Deficient Alkenes.

Selective C-H activation is an area of growing importance. Metal-free C-H activation of branched aldehydes mediating the hydroacylation of electron-deficient alkenes is an attractive transformation, but is limited by selectivity issues, especially in the case of α,α-disubstituted aldehydes. Herein, we report a green, cheap, versatile, and easily reproducible selective hydroacylation of alkenes utilizing phenylglyoxylic acid as the photocatalyst and common household bulbs for irradiation, leading to products in excellent yields and selectivities. The reaction mechanism was also studied to account for the high selectivity.