title: A mechanistic investigation of the photoinduced, copper-mediated cross-coupling of an aryl thiol with an aryl halide.
abstract: Photoinduced, copper-catalyzed cross-coupling can offer a complementary approach to thermal (non-photoinduced) methods for generating C-X (X = C, N, O, S, etc.) bonds. In this report, we describe the first detailed mechanistic investigation of one of the processes that we have developed, specifically, the (stoichiometric) coupling of a copper-thiolate with an aryl iodide. In particular, we focus on the chemistry of a discrete [CuI(SAr)2]-complex (Ar = 2,6-dimethylphenyl), applying a range of techniques, including ESI-MS, cyclic voltammetry, transient luminescence spectroscopy, optical spectroscopy, DFT calculations, Stern-Volmer analysis, EPR spectroscopy, actinometry, and reactivity studies. The available data are consistent with the viability of a pathway in which photoexcited [CuI(SAr)2]-* serves as an electron donor to an aryl iodide to afford an aryl radical, which then reacts in cage with the newly generated copper(II)-thiolate to furnish the cross-coupling product in a non-chain process.
authors.affiliation: Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, 91125, USA.
authors.forename: Miles W
authors.initials: MW
authors.lastname: Johnson
authors.affiliation: Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, 91125, USA.
authors.forename: Kareem I
authors.initials: KI
authors.lastname: Hannoun
authors.affiliation: Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, 91125, USA.
authors.forename: Yichen
authors.initials: Y
authors.lastname: Tan
authors.affiliation: Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, 91125, USA.
authors.forename: Gregory C
authors.initials: GC
authors.lastname: Fu
authors.affiliation: Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, 91125, USA.
authors.forename: Jonas C
authors.initials: JC
authors.lastname: Peters