Iron-catalyzed regioselective reductive cyclotrimerization of alkynyl bromides to 1,2,4-substituted arenes and D3-arenes

Abstract

Herein, we report an iron-catalyzed regioselective reductive cyclotrimerization of alkynyl bromides for the synthesis of 1,2,4-substituted arenes and D₃-arenes, enabled by using MeOH and CD₃OD as proton sources, respectively. A series of 1,2,4-substituted arenes and D₃-arenes bearing various functional groups were successfully obtained in good yields with excellent regioselectivities. Preliminary mechanistic studies suggested that the terminal alkyne generated in situ may act as an intermediate in this cyclotrimerization process.