Cyclization reactions provide an instant and effective path to generate mono- and polycyclic systems and are one of the most important and fundamental fields in organic chemistry. Catalytic transformations involving photoinduced radical-polar crossover cyclization (RPCC) have become highly valuable and powerful processes for transforming simple and readily available alkene precursors into structurally complex cyclic molecular scaffolds; especially, C–X unsaturated bond net-neutral RPCC, in which both the single-electron oxidation and reduction steps occur through interaction with the photocatalyst and without the addition of exogenous oxidants or reductants, is undergoing rapid development. This review will summarize the latest advances in the photoinduced RPCC reactions (only redox-neutral and oxidant/reductant-free transformations were taken into closer consideration) and aims to give an overview of the different existing strategies based on alkene RPCC to photocatalytically build cyclic architectures from radicals and carbon-centered anions or equivalents of those.

环化反应为生成单环和多环体系提供了即时有效的途径，是有机化学中最重要和最基础的领域之一。涉及光诱导自由基-极性交叉环化（RPCC）的催化转化已成为将简单且易于获得的烯烃前体转化为结构复杂的环状分子支架的非常有价值和强大的过程；特别是C-X不饱和键网络中性RPCC，其中单电子氧化和还原步骤通过与光催化剂的相互作用发生，并且不添加外源氧化剂或还原剂，正在快速发展。本综述将总结光诱导 RPCC 反应的最新进展（仅仔细考虑氧化还原中性和无氧化剂/还原剂转化），旨在概述基于烯烃 RPCC 光催化构建循环结构的不同现有策略来自自由基和以碳为中心的阴离子或它们的等价物。