Radical Functionalization of 1,6‐Diene via Transannular Cyano Migration: Synthesis of Polysubstituted Cyclopentanes^†

Comprehensive Summary An efficient transannular cyano migration is reported for gem ‐dicyano‐1,6‐diene, which is triggered by the addition of external arylsulfonyl radicals. The overall transformation proceeds through a sequence of intramolecular 5‐exo‐trig cyclization, suprafacial 1,4‐cyano migration, and the capture by H or D atom, leading to the production of valuable polysubstituted cyclopentanes under mild photoredox catalytic conditions. The reaction is adapted to a wide range of sodium (hetero)arylsulfinates, demonstrating good functional group compatibility. This method provides a new protocol for radical‐mediated functional group migration.