Transition metal-catalyzed aminocarbonylation of aryl halides with CO and amines, pioneered by Heck and co-workers in the 1970s, is among the most commonly employed reactions to make aromatic amides. A catalyst-free aminocarbonylation of aryl iodides with CO and amines, which simply uses photoirradiation conditions by Xe-lamp, has now been developed. This methodology shows broad functional-group tolerance, including that of heteroaromatic amides. A hybrid radical/ionic chain mechanism, involving electron transfer from zwitterionic radical intermediates generated by nucleophilic attack of amines to aroyl radicals, is proposed.
- electron transfer
- radical reactions