title: Mechanistic studies of Pd-catalyzed regioselective aryl C-H bond functionalization with strained alkenes: origin of regioselectivity.
abstract: Mechanistic studies of a palladium-catalyzed regioselective aryl C-H functionalization of 2-pyrrole phenyl iodide with norbornene are presented. Kinetic and spectroscopic analyses together with crystallographic data provide evidence for intermediates in a proposed stepwise mechanism. On the basis of the mechanistic studies, the origin of the regioselectivity is due to a ligand exchange between I(-) and HO(-) on the norbornyl palladium complex. These mechanistic studies also implicate that either alkoxide or water is responsible for the formation of the palladacycle, but a reversible ring-opening-ring-closing process of the palladacycle with HX can retard the rate of reaction of a key intermediate. The significant aspects of the proposed mechanism are discussed in detail.
authors.affiliation: Davenport Chemical Laboratories, Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, ON M5S 3H6, Canada.
authors.forename: David I
authors.initials: DI
authors.lastname: Chai
authors.forename: Praew
authors.initials: P
authors.lastname: Thansandote
authors.forename: Mark
authors.initials: M
authors.lastname: Lautens
mesh_terms: D000475:Alkenes / Q000737:chemistry*; D002384:Catalysis; D018360:Crystallography, X-Ray; D007454:Iodides / Q000737:chemistry; D008958:Models, Molecular; D009636:Norbornanes / Q000737:chemistry*; D010165:Palladium / Q000737:chemistry*; D011758:Pyrroles / Q000737:chemistry; D013237:Stereoisomerism; D014867:Water / Q000737:chemistry
chemical_list: D000475:Alkenes; D007454:Iodides; D009636:Norbornanes; D011758:Pyrroles; D014867:Water; D010165:Palladium