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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 Shell higher olefin process (SHOP) is a chemical process for the production of linear alpha olefins via ethylene oligomerization and olefin metathesis invented and exploited by Shell plc. [1] The olefin products are converted to fatty aldehydes and then to fatty alcohols, which are precursors to plasticizers and detergents.
Reversible-addition-fragmentation chain-transfer polymerization (RAFT polymerization, RAFT): Degenerate-transfer radical polymerization in which chain activation and chain deactivation involve a degenerative chain-transfer process which occurs by a two-step addition-fragmentation mechanism. Note 1: Examples of RAFT agents include certain ...
In organic chemistry, ethenolysis is a chemical process in which internal olefins are degraded using ethylene (H 2 C=CH 2) as the reagent. The reaction is an example of cross metathesis . The utility of the reaction is driven by the low cost of ethylene as a reagent and its selectivity.
Where shorter chains are wanted, as they for the production of surfactants, then processes incorporating a olefin metathesis step, such as the Shell higher olefin process are important. Olefin metathesis is also used commercially for the interconversion of ethylene and 2-butene to propylene. Rhenium- and molybdenum-containing heterogeneous ...
In the ring closing metathesis step, a ruthenium indenylidene complex was used as the precatalyst to afford the desired 7-member ring in 87% yield. [55] In 2002, Stephen F. Martin and others reported the 24-step synthesis of manzamine A with two ring-closing metathesis steps to access the polycyclic alkaloid. [56]
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 ...
Cross-coupling reactions are important for the production of pharmaceuticals, [4] examples being montelukast, eletriptan, naproxen, varenicline, and resveratrol. [21] with Suzuki coupling being most widely used. [22] Some polymers and monomers are also prepared in this way. [23]