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In organic chemistry, olefin metathesis is an organic reaction that entails the redistribution of fragments of alkenes (olefins) by the scission and regeneration of carbon-carbon double bonds. [ 1 ] [ 2 ] Because of the relative simplicity of olefin metathesis, it often creates fewer undesired by-products and hazardous wastes than alternative ...
The metal-mediated processes include a carbonyl-olefination and an olefin–olefin metathesis event. There are two general mechanistic schemes to perform this overall transformation: one, reaction of a [M=CHR 1] reagent with an alkene to generate a new metal alkylidene, which then couples with a carbonyl group to form the desired substituted alkene and an inactive [M=O] species (type A); two ...
At MIT Schrock was the first to elucidate the structure and mechanism of so-called 'black box' olefin metathesis catalysts. He showed that the alpha abstraction reaction could be used to prepare molybdenum or tungsten alkylidene and alkylidyne complexes in large variety through ligand variations.
Ring-closing metathesis (RCM) is a widely used variation of olefin metathesis in organic chemistry for the synthesis of various unsaturated rings via the intramolecular metathesis of two terminal alkenes, which forms the cycloalkene as the E-or Z-isomers and volatile ethylene. [1] [2]
The 2-butenes are then subjected to metathesis with ethylene. Rhenium- and molybdenum-containing heterogeneous catalysis are used. Nowadays, only the "reverse" reaction is practiced, i.e., the conversion of ethylene and 2-butene to propylene: [2] CH 2 =CH 2 + CH 3 CH=CHCH 3 → 2 CH 2 =CHCH 3
Grubbs's main research interests were in organometallic chemistry and synthetic chemistry, particularly the development of novel catalysts for olefin metathesis. In olefin metathesis, a catalyst is used to break the bonds of carbon molecules, which can then re-form to create chemical bonds in new ways, producing new compounds with unique ...
The mechanism of homogeneous ring-opening metathesis polymerization is well-studied. It is similar to any olefin metathesis reaction. Initiation occurs by forming an open coordination site on the catalyst. Propagation happens via a metallacycle intermediate formed after a 2+2 cycloaddition. When using a G3 catalyst, 2+2 cycloaddition is the ...
He then extended his experimentation to internal olefins and cyclic olefins, substances that are not normally polymerized by could serve as olefin metathesis substrates. [7] Many researchers followed on Eleuterio's initial discovery, [ 8 ] culminating in the 2005 Nobel Prize to Chauvin, Grubbs, and Schrock for the development of olefin ...