1 research outputs found
Mechanistic Insights into Grubbs-Type Ruthenium-Complex-Catalyzed Intramolecular Alkene Hydrosilylation: Direct σ‑Bond Metathesis in the Initial Stage of Hydrosilylation
Grubbs-type
ruthenium-complex-mediated intramolecular alkene hydrosilylation
of alkenylsilyl ethers has been developed to provide cyclic silyl
ethers with high regioselectivity. This non-metathetical use of such
ruthenium complexes for alkene hydrosilylation via preferential Si–H
bond activation over alkene activation is notable, where the competing
alkene metathesis dimerization was not detected. In addition to the
synthesis of organosilicon heterocycles from readily available olefins,
this study provides fundamental mechanistic insights into the non-metathetical
function of Grubbs-type ruthenium catalysts. In the initial stage
of hydrosilylation within a ruthenium coordination sphere, evidence
for activation of a ruthenium complex by direct σ-bond metathesis
between Si–H and Ru–Cl via a four-centered transition
state is presented. This study counters the traditionally accepted
Chauvin-type mechanism, specifically the addition of R<sub>3</sub>Si–H across the π-bond of a Ru-benzylidene