Time and Atom Economical Regio- and Chemoselective Radical Cyclization of Unactivated 1,6-Enynes Under Metal- and Oxidant-Free Conditions.

We developed time-atom economic regio- and chemoselective sulfonyl radical triggered 5-exo-dig cyclization of unactivated 1,6-enynes with sulfonyl halides under metal, additive-free reaction conditions to achieve highly substituted five-membered heterocyclic compounds. This transformation creates three new bonds, such as C-SO 2 , C-C, and active C-I/Br bonds. Importantly, one-pot protocols produce desired products directly from sodium sulfinates and have an additional advantage such as minimising chemical waste, saving time, and simplifying practical aspects compared to existing protocols.