The Direct Decarboxylative <i>N</i>-Alkylation of Azoles, Sulfonamides, Ureas, and Carbamates with Carboxylic Acids via Photoredox Catalysis
Peijun Li, Jennifer E. Klomp, Jack A. Terrett
Abstract
Herein, we describe a method for the direct decarboxylative C–N coupling of carboxylic acids with a range of nitrogen nucleophiles. This platform employs visible-light-mediated photoredox catalysis and an iodine(III) reagent to generate carbocation intermediates directly from aliphatic carboxylic acids via a radical-polar crossover mechanism. A variety of C–N bond-containing products are constructed from a diverse array of nitrogen heterocycles, including pyrazoles, imidazoles, indazoles, and purine bases. Furthermore, sulfonamides, ureas, and carbamates can also be utilized as the nucleophile to generate a selection of N-alkylated products. Notably, a two-step approach to construct free amines directly from carboxylic acids is accomplished using Cbz-protected amine as the nucleophile.