title: Iridium-catalyzed regioselective silylation of secondary alkyl C-H bonds for the synthesis of 1,3-diols.
abstract: We report Ir-catalyzed intramolecular silylation of secondary alkyl C-H bonds. (Hydrido)silyl ethers, generated in situ by dehydrogenative coupling of a tertiary or conformationally restricted secondary alcohol with diethylsilane, undergo regioselective silylation at a secondary C-H bond γ to the hydroxyl group. Oxidation of the resulting oxasilolanes in the same vessel generates 1,3-diols. This method provides a strategy to synthesize 1,3-diols through a hydroxyl-directed, functionalization of secondary alkyl C-H bonds. Mechanistic studies suggest that the C-H bond cleavage is the turnover-limiting step of the catalytic cycle. This silylation of secondary C-H bonds is only 40-50 times slower than the analogous silylation of primary C-H bonds.
authors.affiliation: Department of Chemistry, University of California , Berkeley, California 94720, United States.
authors.forename: Bijie
authors.initials: B
authors.lastname: Li
authors.forename: Matthias
authors.initials: M
authors.lastname: Driess
authors.forename: John F
authors.initials: JF
authors.lastname: Hartwig