Metal‐Free Visible‐Light‐Promoted Haloazidation/Cyclization of Phenyl‐Linked 1,6‐Enynes with TMSN₃ and NIS/NBS**

Abstract

A metal‐ and oxidant‐free procedure for the three‐component haloazidation/cyclization of phenyl‐linked 1,6‐enynes with TMSN3 and N‐iodo(bromo)succinimide under the irradiation of visible light was described. Moreover, this reaction involved a radical addition/5‐exo‐dig cyclization/radical coupling process, and realized simultaneous construction of C−N, C−C, and C−X (I, Br) bonds in one step.

Visible light-induced radical cascade acylmethylation/cyclization of 2-(allyloxy)arylaldehydes with α-bromo ketones: access to cyclic 1,5-dicarbonyl-containing chroman-4-one skeletons

“…Therefore, the development of simple and efficient methodologies for the assembly of dicarbonyl-containing chroman-4-ones is highly desirable. Inspired by these results and in continuation of our interest in photocatalytic synthesis and radical enyne-cascade cyclizations, 16 herein, we have developed a metal and oxidant-free, photocatalytic acylmethyl radical-triggered cascade cyclization of 2-(allyloxy)arylaldehydes with α-bromo ketones to afford 1,5-dicarbonyl-containing chroman-4-ones (Scheme 1e).…”