Metal-Free Synthesis of Carbamoylated Chroman-4-Ones via Cascade Radical Annulation of 2-(Allyloxy)arylaldehydes with Oxamic Acids

Abstract

An efficient and straightforward approach for the synthesis of carbamoylated chroman-4-ones has been well-developed. The reaction is triggered through the generation of carbamoyl radicals from oxamic acids under metal-free conditions, which subsequently undergoes decarboxylative radical cascade cyclization on 2-(allyloxy)arylaldehydes to afford various amide-containing chroman-4-one scaffolds with high functional group tolerance and a broad substrate scope.

Persulfate-Promoted Carbamoylation/Cyclization of Alkenes: Synthesis of Amide-Containing Quinazolinones

“…In this context, obvious achievements have been made, especially in the carbamoylation of N -heterocycles through a Minisci-type reaction process [ 55 , 56 , 57 , 58 ]. In recent years, radical difunctionalization reactions of alkenes employing oxamic acids or other carbamoylating reagents such as carbamoyl radical precursors have also provided a promising strategy to introduce amide groups to various complex molecules [ 59 , 60 ]. For instance, in 2021, Wang and co-workers reported persulfate-promoted difunctionalization reactions of ortho-cyanoarylacrylamides with oxamic acids to access a variety of carbamoyl quinoline-2,4-diones [ 61 ].…”