title: Rate-limiting step of the Rh-catalyzed carboacylation of alkenes: C-C bond activation or migratory insertion?
abstract: Rhodium-catalyzed intramolecular carboacylation of alkenes, achieved using quinolinyl ketones containing tethered alkenes, proceeds via the activation and functionalization of a carbon-carbon single bond. This transformation has been demonstrated using RhCl(PPh(3))(3) and [Rh(C(2)H(4))(2)Cl](2) catalysts. Mechanistic investigations of these systems, including determination of the rate law and kinetic isotope effects, were utilized to identify a change in mechanism with substrate. With each catalyst, the transformation occurs via rate-limiting carbon-carbon bond activation for species with minimal alkene substitution, but alkene insertion becomes rate-limiting for more sterically encumbered substrates. Hammett studies and analysis of a series of substituted analogues provide additional insight into the nature of these turnover-limiting elementary steps of catalysis and the relative energies of the carbon-carbon bond activation and alkene insertion steps.
authors: Department of Chemistry, Hope College, 35 East 12th Street, Holland, Michigan 49423, USA.
authors: J Patrick
authors: JP
authors: Lutz
authors: Colin M
authors: CM
authors: Rathbun
authors: Susan M
authors: SM
authors: Stevenson
authors: Breanna M
authors: BM
authors: Powell
authors: Timothy S
authors: TS
authors: Boman
authors: Casey E
authors: CE
authors: Baxter
authors: John M
authors: JM
authors: Zona
authors: Jeffrey B
authors: JB
authors: Johnson