Photoinduced Site-Selective C(sp3)-H Chlorination of Aliphatic Amides

Org Lett. 2020 Nov 20;22(22):8899-8903. doi: 10.1021/acs.orglett.0c03297. Epub 2020 Nov 11.

Abstract

Herein, we report a new photochemical method for C(sp3)-H chlorination of amides which employs tert-butyl hypochlorite as the chlorinating agent and a household compact fluorescent lamp as the light source. The reaction proceeds via N-heterocyclic carbene SIPr·HCl-promoted N-H chlorination and subsequent photoinduced Hofmann-Löffler-Freytag chlorine atom transfer. The latter process is facilitated by (diacetoxyiodo)benzene. This protocol exhibits a broad scope and is suitable for site-selective chlorination of methyl hydrogen as well as methylene and methine hydrogen.