Tricyclohexylphosphine PCy

Chloroaryls, which are electronically deactivated and thus resistant to enter to the oxidative addition, were coupled with phenyltributyltin (PhSnBus) by using tricyclohexylphosphine (Pcys) adducts of palladium in K3PO4 and 1,4-dioxane to yield the corresponding biaryls in good yield. ... 

Among the nickel-based catalysts, beside the nickel on charcoal [43], mainly the various nickel(0)-phosphine complexes were employed [12,13,44,45]. Several common bidentate phosphine ligands such as dppf, dppe, dppp, dppb and tricyclohexylphosphine (PCys) are the most popular in the nickel-based SM crosscoupling reactions of less reactive aryl chlorides with arylboronic acids [44], While the nickel complexes of electron-rich trialkylphosphines react readily with aryl chlorides. 

An important observation regarding Suzuki couplings of aryl chlorides was reported in 1997 by Shen, who established that palladium complexes that include a bulky, electron-rich trialkylphosphine, such as tricyclohexylphosphine (PCys), catalyze Suzuki couphngs of activated aryl chlorides at 100°C (Equation 2.14) [25]. 

Replacement of a phosphine ligand with an A7-heterocycUc carbene (NHC) increases the stability and efficiency of the catalyst precursors, thus affording a second generation of monometallic ruthenium initiators. Several vinylidene complexes [RuCl2(=C=CHR)(PCy3)(NHC)] bearing mixed ligand sets made up of tricyclohexylphosphine (PCys) and Ai-heterocyclic carbenes promoted several RCM and ROMP reactions (Scheme 48) [170, 171]. 

PCys salen=bis(salicylidene)-ethylene-diamine Cy = tricyclohexylphosphine 28.7 0.4 120.0 1.6 ... 

Reaction (21) occurs with cyclohexene and both cis- and frans-2-butene, without isomerization of the alkenes, while the reduction of Ni(acac)2 with Al(alkyl)3 in the presence of PCys and 2-butene (cis and trans) affords the complex bis(tricyclohexylphosphine)(l-butene)nickel(O). 

Sulfine complexes of platinum(II) can be formed by oxidative addition to Pt(PPh3)3. The initial step involves the formation of an ij -CS complex which undergoes intramolecular oxidative addition of a C—S bond (equation 542). Use of Pt(cod)2 and PCys ves the tricyclohexylphosphine analogue. The reaction gives two stereoisomers. The coordination stabilization of sulfines allows their synthesis in the coordination sphere of platinum, but the cyclic process is not very efficient. ... 

The mechanism of reductive elimination with C—C bond formation has been studied for [Ni(CN)PhPa], where P=PEta or PCys (tricyclohexylphosphine). The thermal decomposition of [Ni(CN)Ph(PCy3>2] gives very little PhCN, but with an excess of P(OEt)3 this is formed quantitatively by a reaction, first-order in both complex and triethyl phosphite. An associative reaction with reductive elimination from the five-co-ordinate intermediate is most likely since there is no rate retardation by added PCys, and the rate characteristics are very like those of bimolecular substitution, which, of course, requires the formation of a very similar intermediate. For the reaction of P(OEt)a with [Ni(CN)Ph(PEt3)2] competitive substitution of phosphine by phosphite and reductive elimination need to be considered to account for the kinetics in this case added PEts does lead to rate retardation. Nonetheless, reductive elimination from a five-coordinate species still seems to operate. 

Scheme 11 Conversion of secondary to tertiary alcohols via ruthenium(0)-catalyzed C-C bond forming transfer hydrogenation with conjugated dienes. Yields are of material isolated by flash chromatography on silica get PCys = tricyclohexylphosphine...

Rh-catalyzed Arylation of Heterocycles. Arylation of benzimidazole was achieved using aryl iodides in the presence of a Rh catalyst and 40 mol % of PCys. Other ligands, such as alkyl and aryl phosphines, phosphites, and phosphoramidites, produced inferior conversions compared with tricyclohexylphosphine. Excess phosphine inhibited the reaction, suggesting that phosphine dissociation occurs prior to oxidative addition of the aryl iodide. 

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