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.