Diastereoselective Three‐Component Annulation for the Synthesis of Sulfonylated Polycyclic Indolines

ABSTRACT An additive‐free and metal‐free three‐component radical relay reaction has been achieved to obtain diverse sulfonylated polycyclic indolines with moderate to excellent yields. This innovative protocol offers several significant advantages: (1) it eliminates the need for transition metal catalysts, (2) operates under mild reaction conditions without requiring high temperatures, and (3) demonstrates exceptional diastereoselectivity (dr > 20:1). Comprehensive mechanistic studies have revealed that the transformation proceeds through an intramolecular 1,5‐hydrogen atom transfer (1,5‐HAT) process.