title: Bis(imino)pyridine cobalt-catalyzed dehydrogenative silylation of alkenes: scope, mechanism, and origins of selective allylsilane formation.
abstract: The aryl-substituted bis(imino)pyridine cobalt methyl complex, ((Mes)PDI)CoCH3 ((Mes)PDI = 2,6-(2,4,6-Me3C6H2-N═CMe)2C5H3N), promotes the catalytic dehydrogenative silylation of linear α-olefins to selectively form the corresponding allylsilanes with commercially relevant tertiary silanes such as (Me3SiO)2MeSiH and (EtO)3SiH. Dehydrogenative silylation of internal olefins such as cis- and trans-4-octene also exclusively produces the allylsilane with the silicon located at the terminus of the hydrocarbon chain, resulting in a highly selective base-metal-catalyzed method for the remote functionalization of C-H bonds with retention of unsaturation. The cobalt-catalyzed reactions also enable inexpensive α-olefins to serve as functional equivalents of the more valuable α, ω-dienes and offer a unique method for the cross-linking of silicone fluids with well-defined carbon spacers. Stoichiometric experiments and deuterium labeling studies support activation of the cobalt alkyl precursor to form a putative cobalt silyl, which undergoes 2,1-insertion of the alkene followed by selective β-hydrogen elimination from the carbon distal from the large tertiary silyl group and accounts for the observed selectivity for allylsilane formation.
authors: Department of Chemistry, Frick Laboratory, Princeton University , Princeton, New Jersey 08544, United States.
authors: Crisita Carmen Hojilla
authors: CC
authors: Atienza
authors: Tianning
authors: T
authors: Diao
authors: Keith J
authors: KJ
authors: Weller
authors: Susan A
authors: SA
authors: Nye
authors: Kenrick M
authors: KM
authors: Lewis
authors: Johannes G P
authors: JG
authors: Delis
authors: Julie L
authors: JL
authors: Boyer
authors: Aroop K
authors: AK
authors: Roy
authors: Paul J
authors: PJ
authors: Chirik