title: Copper-catalyzed recycling of halogen activating groups via 1,3-halogen migration.
abstract: A Cu(I)-catalyzed 1,3-halogen migration reaction effectively recycles an activating group by transferring bromine or iodine from a sp(2) to a benzylic carbon with concomitant borylation of the Ar-X bond. The resulting benzyl halide can be reacted in the same vessel under a variety of conditions to form an additional carbon-heteroatom bond. Cross-over experiments using an isotopically enriched bromide source support intramolecular transfer of Br. The reaction is postulated to proceed via a Markovnikov hydrocupration of the o-halostyrene, oxidative addition of the resulting Cu(I) complex into the Ar-X bond, reductive elimination of the new sp(3) C-X bond, and final borylation of an Ar-Cu(I) species to turn over the catalytic cycle.
authors.affiliation: Department of Chemistry, University of Wisconsin, 1101 University Avenue, Madison, Wisconsin 53706, USA.
authors.forename: R David
authors.initials: RD
authors.lastname: Grigg
authors.forename: Ryan
authors.initials: R
authors.lastname: Van Hoveln
authors.forename: Jennifer M
authors.initials: JM
authors.lastname: Schomaker
mesh_terms: D001895:Boron / Q000737:chemistry; D002384:Catalysis; D003300:Copper / Q000737:chemistry*; D006219:Halogens / Q000737:chemistry*; D010084:Oxidation-Reduction; D058105:Polymerization; D020058:Styrene / Q000737:chemistry
chemical_list: D006219:Halogens; D020058:Styrene; D003300:Copper; D001895:Boron