title: Are copper(I) carbenes capable intermediates for cyclopropanations? The case for ylide intermediates.
abstract: A novel approach is used to synthesize a stable, ligated copper(I) carbene in the gas phase that is capable of typical metal carbenoid chemistry. However, it is shown that copper(I) carbenes generally undergo rapid unimolecular rearrangements including insertions into copper-ligand bonds and Wolff rearrangements. The results indicate that most copper(I) carbenes are inherently unstable and would not be viable intermediates in condensed-phase applications; an alternative intermediate that is less prone to rearrangements is required. Computational data suggest that ylides formed by the complexation of the carbene with solvent or other weak nucleophiles are viable intermediates in the reactions of copper(I) carbenes.
authors.affiliation: Department of Chemistry, Virginia Commonwealth University, 1001 W. main St., Richmond, VA 23284 (USA).
authors.forename: Jamal T
authors.initials: JT
authors.lastname: Aldajaei
authors.affiliation: Department of Chemistry and Biochemistry, San Francisco State University, 1600 Holloway Ave, San Francisco, CA 94132 (USA).
authors.forename: James R
authors.initials: JR
authors.lastname: Keeffe
authors.affiliation: Department of Chemistry, Virginia Commonwealth University, 1001 W. main St., Richmond, VA 23284 (USA).
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Swift
authors.affiliation: Department of Chemistry, Virginia Commonwealth University, 1001 W. main St., Richmond, VA 23284 (USA). sgronert@vcu.edu.
authors.forename: Scott
authors.initials: S
authors.lastname: Gronert
keywords: copper carbene; gas phase; mass spectrometry; rearrangement; ylide