Selective production of imines and benzimidazoles by cooperative bismuth(III)/transition metal ion catalysis

Abstract

Cooperative Bi(III)/Co(II) and Bi(III)/Mn(II) heterogeneous catalysts have been developed enabling efficient oxidative annulations for preparing both cross-coupled imines and benzimidazoles under ambient conditions in an atom-economic and time-efficient manner, involving ambient air as oxidant and without the need of any other additives. This is the first synergistic Lewis acid/transition metal catalyzed annulation which is potentiated by the interfaces between the building blocks of the catalysts. To achieve our goals, a useful fabrication process has been developed to heterogenize the transition metal ions via strong interactions on well-known Sillèn-type bismuth subcarbonate (bismutite). Their reusability, activity and selectivity as well as water-tolerance have made them potential competitors to effective heterogeneous/homogeneous catalysts reported previously.