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

摘要

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).