A new cascade three-component halosulfonylation of 1,7-enynes for efficient synthesis of densely functionalized 3,4-dihydroquinolin-2(1H)-ones has been established from readily accessible arylsulfonyl hydrazides and NIS (or NBS). The reaction pathway involves in situ-generated sulfonyl radical-triggered α,β-conjugated addition/6-exo-dig cyclization/radical coupling sequence, resulting in continuous multiple bond-forming events including C–S, C–C and C–I (or C–Br) bonds to rapidly build up molecular complexity.

A metal-free synthesis of bifunctionalized indole derivatives was developed through a novel TBHP/TBAI-mediated oxidative coupling of C2,C3-unsubstituted indoles with arylsulfonyl hydrazide. Under the same conditions C3-methyl substituted indoles underwent a diazotization process, affording 2-sulfonyldiazenyl-1H-indoles. The former reaction simultaneously established C–S and C–N bonds through selective sulfonylation and diazotization of the indole framework, enabling a mild and practical access to polyfunctionalized indoles with good to excellent yields.

A new metal-free oxidative hydrophosphinylation of 1,7-enynes for forming polyfunctionalized 3,4-dihydroquinolin-2(1H)-ones has been realized using readily accessible diarylphosphine oxide and TBPB as an oxidant. The reaction pathway involves an in situ-generated P-centered radical-triggered α,β-conjugate addition/6-exo-dig cyclization/H-abstraction sequence, providing a direct and promising protocol for the formation of C–P, C–C and C–H bonds and rapid construction of complex heterocyclic compounds.