Remote C(sp3)-H Carboxylation with CO2 via Visible-Light-Catalyzed 1,5-Hydrogen Atom Transfer.

The direct carboxylation of C(sp3)-H bonds with CO2 represents a challenging but highly attractive strategy in organic synthesis. In this study, we presented a visible-light-catalyzed strategy for carboxylating remote C(sp3)-H bonds with CO2 via aryl radical induced 1,5-hydrogen atom transfer. This transformation involves generating alkyl radicals via 1,5-hydrogen atom transfer from aryl radicals, forming alkyl carbanions as key intermediates, and a subsequent nucleophilic attack with CO2, thereby enabling access to a variety of tertiary and quaternary carboxylic acids in moderate to good yields.