Organocatalytic Transformation of Aldehydes to Thioesters with Visible Light.

A metal- and oxidant-free catalytic method for accessing structurally diverse thioesters from readily accessible, widespread aldehydes, is described. A strategy of a simple organic 9,10-phenanthrenequinone-promoted hydrogen atom transfer (HAT) with visible light was successfully implemented to selectively generate acyl radicals without inducing crossover reactivity of thioester products. The preparative power of the method was demonstrated by broad substrate scope and wide functional group tolerance, and enabled the late-stage modification of complex structures, which are difficult to achieve with the existing protocols.