Document Type

Article

Publication Date

1-11-2012

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(PPh3)3 and [Rh(C2H4)2Cl]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.