Dicyclohexyl phosphine

However, a truly general method for electron-rich heterocycle arylation was not reported until 2007 [38], Electron-rich, bulky butyl-di-l-adamantylphosphine or /er/-buty I dicyclohexyl phosphine in combination with Pd(OAc)2 afforded the best results, and the former was chosen because of cost considerations. Interestingly, electron-rich AMieterocyclic carbene ligands that facilitate oxidative addition of aryl chlorides to low-valent transition metals are inefficient in heterocycle arylation. A number of structurally diverse electron-rich heterocycles are reactive (Scheme 3). Thiophene, benzothiophene, 1,2- and 1,3-oxazole derivatives, benzofuran, thiazoles, benzothiazole, 1-alkylimidazoles, 1-alky 1-1,2,4-triazoles, and caffeine can be arylated. Electron-rich, electron-poor, and heteroaryl chlorides can be used. 

A unique method of oxidation of primary and secondary alcohols was found by Tamaru, who reported that the Pd-catalyzed oxidation of alcohols with aryl halides proceeds under basic conditions involving /3-H elimination of the alkoxypalladium 1 [1]. Guram et al. reported that cheaply available chlorobenzene can be used for the oxidation of benzyl alcohols and some secondary aliphatic alcohols in toluene at 105 °C using biphenylyl(dicyclohexyl)phosphine (IV-2) as a ligand. Sterically hindered aliphatic alcohol was oxidized using /-BuONa as a base [la]. 

The reaction of isoprene with CO2 in the presence of oraanotin ethoxide and DBU by the use of dicyclohexyl( 3-pyridylethyl)phosphine (106) affords the isomeric esters 107 and 108 by head-to-tail and tail-to-tail dimerizations. Tin ethoxide forms tin carbonate, which seems to be an effective carrier of CO2[100]. 

The catalytic hydrogenation of alkenes by mixed NHC/phosphine complexes of rhodinm was also stndied. Initial resnlts of the hydrogenation of cyclohexene by /ranx-[RhCl(ICy)(L)2] (ICy = M/V -(dicyclohexyl)imidazol-2-ylidene, L = PPhj. 

Moreover, the Nb complex hydrogenates catalytically aryl- and benzyl-substituted phosphine under similar conditions (Scheme 6.16) [149]. Kinetic studies show that the hydrogenation of triphenylphosphine into the monocyclohexyl, dicyclohexyl, and tricyclohexylphosphine are successive reactions, and the rate of hydrogenation of the arylphosphine decreases as the number of cyclohexyl substituents increases [153]. 

Flydroformylation A catalyst solution consisting of dicarbonylacetylacetonato rhodium (I) (0.063 g) and dicyclohexyl-(3-sulfonoylphenyl)phosphine mono sodium salt (1.10 g) in n-methyl pyrrolidinone (NMP) (16.0 g) was placed in a 100 mL stainless steel autoclave at 75 C under 200 psig synthesis gas. After 15 minutes soy methyl esters (34.05 g) were added and the synthesis gas pressure raised and maintained at 400 psig for 3 hrs resulting in the desired conversion of unsaturation. 

Tetrahydrobis(benzofuran) is produced by a tandem cyclization reaction from the bis-vinyl ether on reaction with catalytic quantities of rhodium(l) salts in the presence of electron-rich phosphine ligands <20030L1301>. Thus, employing 10mol% of [RhCl(coe)2]2 with 20mol% of a dicyclohexyl ferrocenyl phosphine ligand produces the bis-cyclized product (coe = cyclooctene Equation 67). 

Preparation.- Trialkyl or triaryl phosphites and trithiophosphites (55) can be obtained in 50-90% yields from white phosphorus, carbon tetrachloride, triethylamine, and the appropriate alcohol, phenol, or thiol in a polar aprotic solvent such as dimethylformamide. A series of racemic phenylbis(dialkylamino)phosphines (56) have been prepared in a one-pot synthesis as shown the bulk of the dicyclohexyl-amino group prevents substitution of the second chlorine atom, and the products (56) are claimed to be stable to air and moisture. In a one-pot synthesis tris(diethylamino)-phosphine has been treated successively with three different alcohols to give a 89% yield of the thiophosphate (57) after oxidation with sulphur. ... 

The results with the dicyclohexyl-, di-/so-propyl- and diphenyl phosphines show that the cr-donor properties of alkyl phosphines are superior to those of aryl phosphines. However, the triazolop3rridine system reflects at the same time the dual properties of phosphines. For instance, in the case of di-zso-propyl phosphine, there is no preferential structure. A and B are in equilibrium with a ratio of 1.04 1.00. In terms of electron density, this phosphine has equal properties of an acceptor and a donor (09DT5068). 

BINAP = 2,2 -bis(diphenylphosphino)-l,l -binaphthyl DPPF = 1,1 -bis(diphenylphosphino)ferrocene PPF-OMe (1) = l-[(2-diphenylphosphino)ferrocenyl]ethyl methyl ether PPF-P( -Bu)2 = l-[(2-diphenylphosphino)ferrocenyl]ethyldi- -butylphopshine D -BPF = 1,1 -bis(di- -butylphosphino)ferrocene Guram s ligand (4b) = dicyclohexyl [2-(2-methyl-l,3-dioxolan-2-yl)phenyl]phosphine ArPR2 (2) = 2-dimethyl amino-2 -dicy cl ohexylphoshino-1,1 -biphenyl. 

Chloro[2-dicyclohexyl(2, 4, 6 -tri-isopropylbiphenyl)phosphine]gold(I) [X-Phos-gold(I) chloride, X-Phos-... 

Azobis (2-methyl-N-phenylpropionamidine) dihydrochloride 2,2 -Azobis (2-methylpropane) 2,2 -Azobis (2-methylpropionamide) dihydrate 2,2 -Azobis [N-(2-propenyl)-2-methylpropionamide] 2,2 -Azobis [2-(3,4,5,6-tetrahydropyrimidin-2-yI) propane] dihydrochloride 2,2 -Azobis (2,4,4-trimethylpentane) n-Butyl-4,4-bis (t-butylperoxy) valerate t-Butyl hydroperoxide t-Butyl peroxycrotonate t-Butyl peroxyneoheptanoate Cerium Cumene hydroperoxide Cumyl peroxyneodecanoate o-Cumylperoxyneoheptanoate 1 -[(1 -Cyano-1 -methylethyl) azo] formamide Decanoyl chloride Decanoyl peroxide Di-t-amyl peroxide 2,2-Di (t-butylperoxy) butane Dicetyl peroxydicarbonate Dicyclohexyl peroxydicarbonate Dimethyl 2,2 -azobis (2-methylpropionate) 2,5-Dimethyl-2,5-di (benzoylperoxy) hexane 2,5-Dimethylhexane-2,5-dihydro peroxide Dimyristyl peroxydicarbonate Di-n-propyl peroxydicarbonate Ethyidibutylperoxybutyrate 3,3,6,6,9,9-Hexamethyl 1,2,4,5-tetraoxa cyclononane Lauroyl chloride Pelargonyl peroxide, 2-Phenylazo-4-methoxy-2,4-dimethylvaleronitrile Phosphine Potassium persulfate Sodium persulfate Succinic acid peroxide... 

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