6728-08-1Relevant academic research and scientific papers
Cationic Tungsten Imido Alkylidene N-Heterocyclic Carbene Complexes That Contain Bulky Ligands
Buchmeiser, Michael R.,Frey, Wolfgang,Musso, Janis V.,Schowner, Roman
, p. 3145 - 3157 (2021/09/30)
Neutral and cationic tungsten imido alkylidene complexes of the general formulas W(NtBu)(CHR1)(OR2)Cl(NHC), W(N-2,6-bis(2,4,6-tri-iPr-C6H4)phenyl)(CHR1)Cl2(NHC), [W(NtBu)(CHR1)(OR2)(NHC)][B(ArF)4] and [W(N-2,6-bis(2,4,6-tri-iPr-C6H4)phenyl)(CHR1)Cl(NHC)][B(ArF)4] (R1= CMe3, CMe2Ph; R2= sterically demanding alkoxide; B(ArF)4= tetrakis(3,5-(CF3)2-C6H3)borate; NHC = N-heterocyclic carbene) were prepared. Two electronically different NHCs, namely 1,3-dimethylimidazol-2-ylidene (IMe) and 1,3-dimethyl-4,5-dichloroimidazol-2-ylidene (IMeCl), as well as a variety of terphenolates and a chiral biphenolate were employed.Z-selective homometathesis (HM) of unfunctionalized olefins was achieved with a selectivity of up to 90% and decent turnover numbers (TON) of up to 480 in the HM of 1-dodecene. Additionally, the reactivity of the cationic tungstentert-butylimido complexes in the reaction with vinyltrimethylsilane and ethylene was investigated, which yielded the corresponding silyl-alkylidene complex and, for the first time, a fully characterized cationic tungsten(IV) NHC ethylene complex.
N-Heterocyclic Carbene Complexes Of Metal Imido Alkylidenes And Metal OXO Alkylidenes, And The Use Of Same
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Paragraph 0181, (2017/03/21)
The invention relates to an N-heterocyclic carbene complex of general formulas I to IV (I) (II) (III) (IV), according to which A1 stands for NR2 or PR2, A2 stands for CR2 R2′, NR2, PR2, 0 or S, A3 stands for N or P, and C stands for a carbene carbon atom, ring B is an unsubstituted or a mono or poly-substituted 5 to 7-membered ring, substituents R2 and R2′ stand, inter alia, for a linear or branched C1-Cw-alkyl group and, if N and N each stand for NR2 or PR2, are the same or different, M in formulas I, II, III or IV stands for Cr, Mo or W, X 1 or X2 in formulas I to IV are the same or different and represent, inter alia, C1-C1s carboxylates and C1-C1s-alkoxides, Y is inter alia oxygen or sulphur, Z is inter alia a linear or branched C1-Cw-alkylenoxy group, and R 1 and R1′ in formulas I to IV are, inter alia, an aliphatic or aromatic group. These compounds are particularly suitable for use as catalysts for olefin metathesis reactions and have the advantage, compared to known Schrock carbene complexes, of displaying clearly increased tolerance to functional groups such as, in particular, aldehydes, secondary amines, nitriles, carboxylic acids and alcohols.
Allyl sulphides in olefin metathesis: Catalyst considerations and traceless promotion of ring-closing metathesis
Edwards, Grant A.,Culp, Phillip A.,Chalker, Justin M.
supporting information, p. 515 - 518 (2015/02/19)
Allyl sulphides are reactive substrates in ruthenium-catalysed olefin metathesis reactions, provided each substrate is matched with a suitable catalyst. A profile of catalyst activity is described, along with the first demonstration of allyl sulphides as traceless promoters in relayed ring-closing metathesis reactions. This journal is
One-step, enantiospecific transformation of cyclic, five-membered-1, 2-diols into their respective 1,2-bis(phenylsulfanyl) derivatives
Skarzewski, Jacek,Gupta, Anil,Wojaczyńska, Elzbieta,Siedlecka, Renata
, p. 1615 - 1618 (2007/10/03)
The enantiomeric cyclic, five-membered vic-diols reacted with (PhS) 2/Bu3P in benzene at 80 °C giving the corresponding bis(phenylsulfanyl) derivatives (42-74%) with complete inversion of configuration at both stereogenic centers. Si
Efficiency of a ruthenium catalyst in metathesis reactions of sulfur-containing compounds
Spagnol, Gaelle,Heck, Marie-Pierre,Nolan, Steven P.,Mioskowski, Charles
, p. 1767 - 1770 (2007/10/03)
1,3-Dimesitylimidazol-2-ylidene ruthenium benzylidene catalyst (RuCl2(=C(H)Ph)(PCy3)(IMes)) has been successfully employed in ring-closing metathesis reactions of acyclic diene sulfides, disulfides, and dithianes and in self-cross metathesis reactions of ene-sulfides, thioethers and thiols.
