Rhodium-catalyzed C-H functionalization-based approach to eight-membered lactams

Chem Sci. 2015 Apr 1;6(4):2275-2285. doi: 10.1039/c5sc00092k. Epub 2015 Feb 5.

Abstract

A Rh(iii) catalyzed formal [4 + 2 + 2] cyclization of N-pivaloyloxybenzamides 1 with 1,6-allene-enes 2 by C-H functionalization is reported. The reactions occur at room temperature and are compatible with air and moisture with a tolerance of many synthetically useful functional groups. The follow-up modifications of the products have been demonstrated. After careful mechanistic studies and DFT calculation, a reaction mechanism was proposed.