Recent Advances in Radical Coupling Reactions Directly Involving Bicyclo[1.1.1]pentane (BCP).

BCP (bicyclo[1.1.1]pentane) is an ideal saturated carbon bioisostere, instead of the traditional benzene group, which has been extensively developed. As a novel building block, BCP could be directly involved in a variety of synthetic methods and widely used in the last-stage modification of drugs, attracting much attention from organic chemists and pharmacists. Radical-type cross-coupling reactions involving BCP enable the simultaneous formation of multiple chemical bonds (e.g., C-C, C-N, C-B, C-S, and C-Si) through metal catalysis, photocatalysis, metal-photo synergistic catalysis, and other catalytic systems. Various radical precursors have been explored, facilitating cross-coupling reactions that directly incorporate BCP. This review highlights these state-of-the-art radical couplings of BCP since 2017, organized by reaction components with emphasis on the scope of substrates, reaction mechanisms, and synthetic applications.