EnT-catalysis-enabled, radical-relay cascade cyclization to access multisubstituted cyclohexane/cyclohexene

Abstract

Visible-light-mediated triplet–triplet energy transfer (EnT) catalysis has gained increasing attention, especially for exploiting facile EnT-enabled transformations. Here, we developed an EnT-catalyzed radical-relay cyclization strategy to synthesize a diversity of multisubstituted cyclohexane and cyclohexene frameworks. The core of this strategy is the rational design of a new bifunctional reagent, namely diphenylmethane O-(2,2-dimethyl-4-phenylpent-4-enyl) oxime, which acts as dual radical precursors to react with various alkenes and alkynes. This method exhibits a simple operation, broad substrate scope and excellent diastereoselectivity. Furthermore, the cyclohexane product could be easily transferred to 6-azabicyclo[3.2.1]octan-7-one derivatives. Overall, this method provides a concise and environmentally friendly approach to accessing multisubstituted cyclohexane and cyclohexene molecules through energy transfer catalysis.