Chemodivergent Metathesis of Dienynes Catalyzed by Ruthenium-Indenylidene Complexes: An Experimental and Computational Study

摘要

A study on the enyne meta-thesis reaction leading to the formationcyclic compounds using ruthenium–in-denylidene complexes is presented.Several 1,11-dien-6-ynes have beensubjected to ruthenium metathesis cyc-lization by using ruthenium–indenyli-dene complexes bearing various phos-phine and N-heterocyclic carbene(NHC) ligands. Interestingly, for somesubstrates chemodivergent metathesis occurs and is a function of the catalystemployed. This led us to investigatethe competing "ene-then-yne" or "yne-then-ene" reaction pathways apparent-ly at play in these systems using both experimental observations and DFTcalculations. Experimental and compu-tational studies were found in goodagreement and permit to conclude thatfor phosphine-containing catalysts, the"ene-then-yne" pathway is exclusivelyadopted. On the other hand, for cata-lysts bearing NHC ligands, both path-ways are possible.