Direct C(sp²)‐H Arylsulfonylation of Enamides via Iridium(III)‐Catalyzed Insertion of Sulfur Dioxide with Aryldiazonium Tetrafluoroborates

Abstract

An iridium(III)-catalyzed three-component reaction of enamides, aryldiazonium tetrafluoroborates, and 1,4-diazabicyclo[2.2.2]octane bis(sulfur dioxide) (DABSO) for the direct C(sp 2 )À H arylsulfonylation of enamides is developed. This transformation provides a robust and straightforward approach for preparing a diverse array of βamidovinyl sulfones in moderate to excellent yields and high stereoselectivities without Light-emitting diode (LED) radiation. This transformation also features mild conditions, broad substrate scopes, and excellent functional group tolerance.

Photoredox-catalyzed stereoselective alkylation of enamides with N-hydroxyphthalimide esters via decarboxylative cross-coupling reactions

“…As a crucial subclass of enamines endowed with a delicate balance of reactivity and stability, enamides have attracted increasing attention among the chemical community as pivotal and versatile building blocks which are of recognized synthetic value in the construction of biologically and pharmaceutically active molecules,1 especially small but complex nitrogen-containing compounds 2. In the past few decades, we have witnessed a booming development in new synthetic strategies for the regio- and stereo-selective functionalization of enamides, especially at their β-C(sp 2 )–H bond, which are capable of producing enamides bearing a diverse array of functional groups through arylation,3 alkenylation,4 trifluoromethylation,5 difluoroacetylation,6 alkynylation,7 acylation,8 sulfonylation9 and other useful transformations 10. Nevertheless, the coupling of alkyl moieties to enamides has been considered a more challenging task with scarce advances demonstrated 11.…”

New Application of Natural Language Processing（NLP）for Chemist Predicting Intermediate and Providing an Effective Direction for Mechanism Inference

“…The following process is as the same as Li's inference. And subsequent researches also indicated that free aryl radical is not generated in the previously reported visible light-induced cyclization of 1,6-enynes with aryl sulfony.l [61][62][63] Furthermore, in view of the difference in reactivity between alkyne and alkene, alkyne π-bond is stronger and less reactive than the π-bond of alkene. [50][51] Thus, the addition of sulfonyl radical into the terminal activated alkene to provide the tertiary alkyl radical is more reasonable.…”

DABSO as a SO2 gas surrogate in the synthesis of organic structures

“…68 In another research study, an iridium(III) catalytic system was employed for the insertion of sulfur dioxide with aryldiazonium tetrafluoroborates. 69 A highly regio-and stereoselective arylsulfonylation was catalyzed by Cu(OTf ) 2 . 70 Regarding the abovementioned synthesis, Das et al designed a hydroarylsulfonylation by the use of PhSH as a hydrogen atom transfer agent to react with intermediate 49 (Scheme 27).…”