A copper(ii)-catalyzed three-component reaction of aryldiazonium tetrafluoroborates, sulfur dioxide, with alkenes

Abstract

A three-component reaction of aryldiazonium tetrafluoroborates, sulfur dioxide, with alkenes catalyzed by copper(ii) bromide is developed, which provides an efficient route to (E)-alkenyl sulfones or allylic sulfones via the insertion of sulfur dioxide.

Radicals and Sulfur Dioxide: A Versatile Combination for the Construction of Sulfonyl‐Containing Molecules

“…[44] Reproducibility of the report by Feng andc o-workers is questionable:T he authors claim successful reactions with extremelyu nstable alkyldiazonium salts [44] and Wu und co-workers could not reproduce some of the reported key experiments. [43] Ar adicalm echanism is assumedf or both transformations. The proposed mechanism fort he copper-catalyzed reaction is depicted in Scheme 10.…”

“…Indeed, the groups of Jie Wu from Fudan University and Bainan Feng from Jiangnan University were able to develop 3‐component reactions for the synthesis of vinyl sulfones ( 26 ) starting from arenediazonium tetrafluoroborates ( 24 ), alkenes ( 25 ) and the sulfur dioxide surrogate DABCO ⋅ 2 SO 2 (Scheme ). Wu and co‐workers used a copper salt to catalyze their transformation (Method A), whereas the Feng group employed a combination of tetrabutylammonium iodide (TBAI) and tert ‐butylhydroperoxide (TBHP) (Method B) . Reproducibility of the report by Feng and co‐workers is questionable: The authors claim successful reactions with extremely unstable alkyldiazonium salts and Wu und co‐workers could not reproduce some of the reported key experiments …”

“…Wu and co‐workers used a copper salt to catalyze their transformation (Method A), whereas the Feng group employed a combination of tetrabutylammonium iodide (TBAI) and tert ‐butylhydroperoxide (TBHP) (Method B) . Reproducibility of the report by Feng and co‐workers is questionable: The authors claim successful reactions with extremely unstable alkyldiazonium salts and Wu und co‐workers could not reproduce some of the reported key experiments …”

Design and Applications of a SO2 Surrogate in Palladium‐Catalyzed Direct Aminosulfonylation between Aryl Iodides and Amines

“…[17] In addition, ex-situ-generated gaseous SO 2 could be applied as the source of the sulfonyl group in the synthesis of (E)-alkenyl sulfone 9 starting from aryldiazonium tetrafluoroborates and alkenes catalyzed by CuBr 2 (Scheme 3-6). [18] Lastly,t he twochamber method with our new SOgen proved compatible with small heterocyclic molecules such as indole and 8-aminoquinoline for producing the corresponding 2-sulfonated indole 10 [19] and 5-sulfonyl-8aminoquinoline amide ( 11), [20] respectively,t hrough metalcatalyzed direct CÀHf unctionalization (Scheme 3-7 and -8).…”

Design and Applications of a SO2 Surrogate in Palladium‐Catalyzed Direct Aminosulfonylation between Aryl Iodides and Amines

“…Our SO 2 precursor could furthermore successfully be utilized in the four‐component reaction between aryldiazonium tetrafluoroborates, sulfur dioxide, hydroxylamines, and alkenes, generating the desired compound 8 in 80 % yield (Scheme 3‐5) [17] . In addition, ex‐situ‐generated gaseous SO 2 could be applied as the source of the sulfonyl group in the synthesis of ( E )‐alkenyl sulfone 9 starting from aryldiazonium tetrafluoroborates and alkenes catalyzed by CuBr 2 (Scheme 3‐6) [18] . Lastly, the two‐chamber method with our new SOgen proved compatible with small heterocyclic molecules such as indole and 8‐aminoquinoline for producing the corresponding 2‐sulfonated indole 10 [19] and 5‐sulfonyl‐8‐aminoquinoline amide ( 11 ), [20] respectively, through metal‐catalyzed direct C−H functionalization (Scheme 3‐7 and ‐8).…”