Visible light-driven carbamoyloxylation of the α-C(sp3)–H bond of arylacetones via radical-initiated hydrogen atom transfer

Abstract

Photocatalytic synthesis has emerged as an efficient route to transform CO₂ into functionalized organic carbamates by photocatalysis. Herein, a catalyst-free carbamoyloxylation of arylacetones with CO₂ and amines under visible light was developed for the synthesis of O-β-oxoalkyl carbamates in yields up to 93%. This protocol proceeded smoothly with the assistance of inexpensive carbon tetrabromide at room temperature under atmospheric CO₂ pressure, leading to simultaneous construction of C–O and C–N bonds. Mechanism studies suggested the photoinduced hydrogen atom transfer (HAT) pathway followed by radical addition or single electron transfer (SET).