Copper-catalyzed radical Heck type cyclization: a three-component reaction of DABCO·(SO₂)₂, aryldiazonium tetrafluoroborates and dienes toward sulfonated benzo- seven-membered nitrogen heterocycles

Abstract

A three-component reaction of the sulfur dioxide surrogate of DABCO·(SO2)2, aryldiazonium tetrafluoroborates and dienes has been developed, affording a series of sulfonated nitrogen heterocycles.

Recent Development of Aryl Diazonium Chemistry for the Derivatization of Aromatic Compounds

“…The cyclization strategy merged with the insertion of SO 2 allows the synthesis of sulfonated seven-membered rings, including the Cu-catalyzed three-component reaction to afford sulfonated benzo-fused seven-membered nitrogen heterocycles 292 , and catalyst-free protocol for synthesizing sulfonated [3,1]-benzothiazepines 294 (Scheme ). These two protocols represent the efficient and attractive strategy for preparing seven-membered heterocyclic compounds containing a sulfonyl group through a radical-type cyclization pathway.…”

Low‐Cost Transition Metal‐Catalyzed Heck‐Type Reactions: An Overview

“…In 2018, the research group of Cheng devised an efficient protocol to access a series of sulfonated benzo‐seven membered nitrogen heterocycles 16 via a three‐component reaction [39] . Dienes 13 , aryldiazonium tetrafluoroborates 14 and DABCO‐(SO 2 ) 2 15 reacted via a radical Heck type reaction with Cu(OTf) 2 to give the corresponding heterocyclic products 16 (Scheme 5).…”

The synthesis of seven- and eight-membered rings by radical strategies

“…Cheng's group described a Cu-catalyzed three-component cascade cyclization reaction of aryldiazonium tetrafluoroborates and DABCO•(SO 2 ) 2 for the synthesis of sulfonyl-containing benzazepine present in useful drug molecules (Scheme 7). 25 This strategy only required a small amount of Cu(OTf ) 2 as the catalyst and 1,2-dichloroethane (DCE) : i PrOH = 10 : 1 as the co-solvent under nitrogen atmosphere without any additional oxidant. A wide variety of functional groups have been evaluated and have found good tolerance to various substitutions on the benzene ring of both the substrate and aryldiazonium tetrafluoroborates.…”