title: Ruthenium-catalyzed regiospecific borylation of methyl C-H bonds.
abstract: We report the regiospecific, ruthenium-catalyzed borylation of saturated terminal C-H bonds. Alkylboronates were obtained in 78-98% yields. The borylations of alkanes, trialkylamines, protected alcohols, and fluoroalkanes occurred regiospecifically at the methyl group that is least sterically hindered. In contrast to most organometallic C-H activation, the reactions of alkanes occurred in higher yields than the reactions of arenes. Reactions were conducted that probed steric and electronic effects on the alkyl borylation. These reactions showed that the borylation occurred preferentially at the methyl group that is least sterically hindered and most electron-deficient. Ruthenium compounds containing boryl ligands were synthesized, and one was characterized by X-ray crystallography. One of these compounds contained a rare bridging boryl ligand and served as a catalyst precursor for the borylation of octane.
authors.affiliation: Department of Chemistry, Yale University, P.O. Box 208107, New Haven, Connecticut 06520-8107, USA.
authors.forename: Jaclyn M
authors.initials: JM
authors.lastname: Murphy
authors.forename: Joshua D
authors.initials: JD
authors.lastname: Lawrence
authors.forename: Kazumori
authors.initials: K
authors.lastname: Kawamura
authors.forename: Christopher
authors.initials: C
authors.lastname: Incarvito
authors.forename: John F
authors.initials: JF
authors.lastname: Hartwig
mesh_terms: D001896:Boron Compounds / Q000138:chemical synthesis*; D002244:Carbon / Q000737:chemistry*; D002384:Catalysis; D006859:Hydrogen / Q000737:chemistry*; D008697:Methane / Q000031:analogs & derivatives*; D008956:Models, Chemical; D009942:Organometallic Compounds / Q000138:chemical synthesis*; D012428:Ruthenium / Q000737:chemistry*
chemical_list: D001896:Boron Compounds; D009942:Organometallic Compounds; D002244:Carbon; D012428:Ruthenium; D006859:Hydrogen; D008697:Methane