This reaction is a variation of olefin metathesis ...
This work helped to validate the Chauvin mechanism for olefin metathesis ...
Decomposition of Ruthenium Olefin Metathesis …
These salt metathesis events have a profound effect on the observed rate of the cyclometalation reaction when starting from dichloride complexes (Table ).
Ring-opening metathesis polymerization (ROMP) is a type of olefin metathesis chain-growth polymerization that produces industrially important products ...
Salt metathesis reaction - WikiVisually
The work began with the formation of a chiral N-tert-butanesulfinimine from the aldehyde shown and readily available (R)-tert-butanesulfinamide, which was then allylated stereoselectively using an organoindium species. Treatment of the product with 4 M HCl followed by magnesium in methanol cleaved off the chiral auxiliary and the tosyl group to give the chiral homoallylic amine. This was alkylated with known (Z)-2-iodobutenyl bromide and then acylated with bromoacetyl chloride. Cross metathesis with methyl acrylate was (unsurprisingly) selective for the unhalogenated double bond, and the -unsaturated ester required for the cascade sequence was obtained in good yield. Treatment of this compound with silver triflate and 2,6-di-tert-butyl-4-methylpyridine (DTBMP) effected the anticipated cyclisation to the spiroindolenine, and subsequent addition of DBU caused formation of the E ring by a Baylis-Hillman reaction. I've never seen this reaction done with DBU, which is notoriously non-nucleophilic, but it seems to work well here.
Several ruthenium-based olefin metathesis catalysts of the formula (PR3)2X2RuCHCHCPh2 have been synthesized, and relative catalyst activities were determined by monitoring the ring-closing metathesis of the acyclic diene diethyl diallylmalonate. The following order of increasing activity was determined: X = I 3 = PPh3 ≪ PPr2Ph 2Ph Pr3 3. Additional studies were conducted with the catalyst (PCy3)2Cl2RuCH2 to probe the mechanism of olefin metathesis by this class of catalysts. The data support a scheme in which there are two competing pathways: the dominant one in which a phosphine dissociates from the ruthenium center and a minor one in which both phosphines remain bound. Higher catalyst activites could be achieved by the addition of CuCl to the reaction.
"Mechanism of the olefin metathesis reaction"
The resulting ruthenium alkyl complexes are unusually stable, and these benzylidene complexes exhibit high levels of -selectivity in olefin metathesis reactions.
Both the carboxylate ligand and the aryl group of the N-heterocyclic carbene were altered and the resulting catalysts evaluated using a range of metathesis reactions.
DFT study on the organocatalytic carbonyl–olefin metathesis
Observations on silver salt metathesis reactions with …
sets can be counted at least twenty lexemes in which metathesis occurred in one or more of the Lampungic isolects ...
Well-Defined Ruthenium Olefin Metathesis Catalysts: Mechanism and ..
olefin migration, and thus lead to unwanted byproducts in cross metathesis reactions.
Well-Defined Ruthenium Olefin Metathesis Catalysts: ..
pathways of a Grubbs 2nd-generation olefin metathesis catalyst using d.
Olefin metathesis - ScienceDirect
or silyl ether or acetate ester, a ketone, or a dioxolane such as H2C:CH(CH2)3CONR(CH2)8CH:CH (R = H, Boc) underwent stereoselective ring-closing metathesis reactions to give thirteen- to twenty-membered macrocyclic disubstituted alkenes such as II in 30-75% yields as mainly their (Z)-isomers (E:Z = 65:35-94:6).
Olefin Metathesis | Chemical Reactions | Polymerization
in 32-62% yields and in >95:5 stereoselectivities by ring-closing alkene metathesis reactions of α,ω-dienes with (Cy3P)2RuCl2(:CHPh) (Cy = cyclohexyl) followed by selective ethenolysis of the minor (Z)-diastereomers in the mixt.
• Olefin metathesis - pyrrole formation ..
is intramolecular (in an enyne) it is called ring-closing enyne metathesis or RCEYM (scheme 2) with Y representing oxygen or nitrogen and n an integer ...
Preparation and use It prepared by the salt metathesis reaction of ..
It was demonstrated that ruthenium-based Z-selective metathesis provides an attractive route to form complex internal olefins in good yields with high cis-selectivity, and could emerge as a viable alternative to other popular methods used to form cis olefins, such as the partial hydrogenation of alkynes and the Wittig reaction.
Relay cross metathesis reactions of vinylphosphonates
A five-membered chelated catalyst that was successfully employed in Z-selective cross metathesis reactions has now been found to be highly active for Z-selective ethenolysis at low ethylene pressures, while tolerating a wide variety of functional groups.
Highly stereoselective metathesis reaction ..
This phenomenon also affects its activity in cross metathesis reactions and prohibits crossover reactions of internal olefins via trisubstituted ruthenacyclobutane intermediates.
"I have always been impressed by the quick turnaround and your thoroughness. Easily the most professional essay writing service on the web."
"Your assistance and the first class service is much appreciated. My essay reads so well and without your help I'm sure I would have been marked down again on grammar and syntax."
"Thanks again for your excellent work with my assignments. No doubts you're true experts at what you do and very approachable."
"Very professional, cheap and friendly service. Thanks for writing two important essays for me, I wouldn't have written it myself because of the tight deadline."
"Thanks for your cautious eye, attention to detail and overall superb service. Thanks to you, now I am confident that I can submit my term paper on time."
"Thank you for the GREAT work you have done. Just wanted to tell that I'm very happy with my essay and will get back with more assignments soon."