Cu‐Promoted Sydnone Cycloadditions of Alkynes: Scope and Mechanism Studies. Issue 8 (30th December 2014)

• Record Type: Journal Article
• Authors: Comas‐Barceló, Júlia; Foster, Robert S.; Fiser, Béla; Gomez‐Bengoa, Enrique; Harrity, Joseph P. A.
• Is Part Of: Chemistry. Volume 21:Issue 8(2015)
• Page Start: 3257
• Page End: 3263
• Publication Date: 2014-12-30
• Subjects: Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201406118
• Languages: English
• ISSNs: 0947-6539

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>Cu salts have been found to promote the cycloaddition reaction of sydnones and terminal alkynes, providing significant reduction in reaction times. Specifically, the use of Cu(OTf)₂ is found to provide 1, 3‐disubstituted pyrazoles, whereas simply switching the promoter system to Cu(OAc)₂ allows the corresponding 1, 4‐isomers to be produced. The mechanism of the Cu‐effect in each case has been investigated by experimental and theoretical studies, and they suggest that Cu(OTf)₂ functions by Lewis acid activation of the sydnone, whereas Cu(OAc)₂ promotes formation of reactive Cu^I acetylides.</p> </abstract>