Photoredox-Catalyzed C-H Trideuteromethylation of Quinoxalin-2(1 H )-ones with CDCl 3 as the "CD 3 " source.

Herein, readily available and inexpensive CDCl ₃ was first identified as a new trideuteromethylation reagent under photoredox-catalyzed conditions. Thus, a facile photocatalytic protocol for the C-H trideuteromethylation of quinoxalin-2(1 H )-one was achieved. This operationally straightforward transformation displays a broad scope and provides a new route to introduce the trideuteromethyl group (CD ₃ ) with excellent levels of deuterium content.