Recent Advances in Copper-Catalyzed Oxidative Cyclization Reactions

Abstract

In this review, we have presented an overview on the copper-catalyzed oxidative cyclization reactions over the period from 2020 to the present. In general, both Cu(II) and Cu(I) can be used as starting catalysts, but the reaction mechanisms were different. For example, from the perspective of reaction mechanism, as a starting catalyst, Cu(II) was often directly combined with oxidants to participate in the catalytic oxidation of intermediates or substrates. When Cu(I) served as the starting catalyst, it directly promoted the cleavage of N−O bonds or coordinated with alkyne bonds, while oxidants were used for the subsequent oxidation of intermediates. The experimental results showed that most of the copper-catalyzed oxidative cyclization strategies have achieved satisfactory results.