Recent advances in radical-mediated [2+2+m] annulation of 1,n-enynes

1, n -Enynes are a versatile class of unsaturated hydrocarbons that find broad applications in the synthetic community of natural products, biologically active structures and functional materials. Typical methods for the transformations of 1, n -enynes include the radical-mediated [2+2+ m ] annulation reaction as they are particularly efficient accesses to functionalized polycyclic compounds. We herein highlighted recent process in the radical-mediated [2+2+ m ] annulation of 1, n -enynes, including [2+2+1] and [2+2+2] modes, for the construction of five- to six-membered-ring-fused polycyclic scaffolds. Meanwhile, the mechanisms for these transformations were described.