The Janus face of high trans-effect carbenes in olefin metathesis: gateway to both productivity and decomposition.

ABSTRACT: Ruthenium-cyclic(alkyl)(amino)carbene (CAAC) catalysts, used at ppm levels, can enable dramatically higher productivities in olefin metathesis than their N-heterocyclic carbene (NHC) predecessors. A key reason is the reduced susceptibility of the metallacyclobutane (MCB) intermediate to decomposition via β-H elimination. The factors responsible for promoting or inhibiting β-H elimination are explored via density functional theory (DFT) calculations, in metathesis of ethylene or styrene (a representative 1-olefin) by Ru-CAAC and Ru-NHC catalysts. Natural bond orbital analysis of the frontier orbitals confirms the greater strength of the orbital interactions for the CAAC species, and the consequent increase in the carbene trans influence and trans effect. The higher trans effec

SUBMITTER: Occhipinti G 

PROVIDER: S-EPMC9093171 | biostudies-literature | 2022 May

REPOSITORIES: biostudies-literature