Diphenyl rhodium

C4,Hj,P, Phosphine, 2- (diphenylphos-phino)methyl]-2-methyl-l, 3-propane-diyl]bis(diphenyl-, rhodium complex, 27 287... 

Phosphine, (2-bromophenyl)dichloro-, 2,991 Phosphine, (w-chloroalkyl)dichloro-, 2, 991 Phosphine, chlorodimethyl-, 2, 991 Phosphine, chloro(dimethylamino)-, 2, 991 Phosphine, chlorodiphenyl-, 2, 990 Phosphine, cyclohexyl(o-anisyl)methyl-rhodium complexes asymmetric hydrogenation, 6, 251 Phosphine, [(dialkylphosphino)alkyl]diphenyl-, 2, 994 Phosphine, dichloromethyl-, 2, 991 Phosphine, dichlorophenyl-, 2, 990 Phosphine, diethylphenyl-, 2, 992 Phosphine, dimethyl-, 2,992 Phosphine, dimethylphenyl-, 2,992 Phosphine, diphenyl-, 2, 992 Phosphine, ethyldiphenyl-, 2, 992 Phosphine, ethylenebis(diethyl-, 2, 993 Phosphine, ethylenebis(diphenyl-, 2,993 Phosphine, ethylenebis(phenyl-, 2,992 Phosphine, ethylidynetris[methylene(diphenyl-, 2,994 Phosphine, [(ethylphenylphosphino)hexyl]diphenyl-, 2, 994... 

Phosphine, methyl-n-propylphenyl-rhodium complexes asymmetric hydrogenation, 6,250 Phosphine, neomenthyldiphenyl-rhodium complexes asymmetric hydrogenation, 6,250 Phosphine, phenyl-, 2,992 Phosphine, o-phenylenebis(dimethyl-, 2,993 Phosphine, p-phenylenebis(diphenyl-, 2,993 Phosphine, seleno-metal complexes, 2,664 bidentatc, 2, 664 Phosphine, triaryl-photographic stabilizer, 6,103 Phosphine, tributyl-, 2, 992 oxide... 

Arylation of alkynes via addition of arylboronic acids to alkynes represents an attractive strategy in organic synthesis. The first addition of arylboronic acids to alkynes in aqueous media catalyzed by rhodium was reported by Hayashi et al.89 They found that rhodium catalysts associated with chelating bisphosphine ligands, such as 1,4-Ws(diphenyl-phosphino)butane (dppb) and 1,1 -/ E(diphenylphospliino)fcrroccnc... 

Rhodium and ruthenium complexes have also been studied as effective catalysts. Rh(diphos)2Cl [diphos = l,2-bis(diphenyl-phosphino)ethane] catalyzed the electroreduction of C02 in acetonitrile solution.146 Formate was produced at current efficiencies of ca. 20-40% in dry acetonitrile at ca. -1.5 V (versus Ag wire). It was suggested that acetonitrile itself was the source of the hydrogen atom and that formation of the hydride HRh(diphos)2 as an active intermediate was involved. Rh(bpy)3Cl3, which had been used as a catalyst for the two-electron reduction of NAD+ (nicotinamide adenine dinucleotide) to NADH by Wienkamp and Steckhan,147 has also acted as a catalyst for C02 reduction in aqueous solutions (0.1 M TEAP) at -1.1 V versus SCE using Hg, Pb, In, graphite, and n-Ti02 electrodes.148 Formate was the main... 

Other phosphine systems have been reported in which four phenyl groups are oriented around a rhodium center (249-254). They all hydrogenate Z-enamides efficiently, and intermediates with a conformation of edge-face phenyls seem plausible in each case. The 2S,4S-4-diphenyl-... 

A new class of phosphines (30) containing only an axial element of chirality (atropisomerism) has been made (253, 254). An in situ 1 1 rhodium/2,2-bis(diphenylphosphinomethyl)-1,1 -binaphthyl system (30a) hydrogenated a-acetamidocinnamic acid to a 54% ee (S) using 50 atm H2, the solvent not being recorded (253). The corresponding diphenyl-phosphinite system (30b) in toluene-acetone was particularly effective (76% ee) for hydrogenation (95 atm) of a-acetamidocinnamic and a-acet-amidoacrylic esters (254). 

Rhodium(i) complexes are excellent catalysts for the 1,4-addition of aryl- or 1-alkenylboron, -silicon, and -tin compounds to a,/3-unsaturated carbonyl compounds. In contrast, there are few reports on the palladium(n) complex-catalyzed 1,4-addition to enones126,126a for the easy formation of C-bound enolate, which will result in /3-hydride elimination product of Heck reaction. Previously, Cacchi et al. described the palladium(n)-catalyzed Michael addition of ArHgCl or SnAr4 to enones in acidic water.127 Recently, Miyaura and co-workers reported the 1,4-addition of arylboronic acids and boroxines to a,/3-unsaturated carbonyl compounds. A cationic palladium(n) complex [Pd(dppe)(PhCN)2](SbF6)2 was found to be an excellent catalyst for this reaction (dppe = l,2-bis(diphenyl-phosphine)ethane Scheme 42).128... 

The first example of an enantioselective [5 + 2]-cycloaddition was reported for the tethered alkene-VCP 7a, which upon treatment with a chiral rhodium complex afforded the m-fused bicyclo[5.3.0]decene 8a in 80% yield and 63% enantiomeric excess (ee) (Equation (6)).39 A later study found that when a 2,2-bis(diphenyl-phosphanyl)-l,l-binaphthyl (BINAP)-modified rhodium(l) catalyst is used, good to excellent ee s and yields are achieved with a variety of substrates (Equation (7)).40... 

Addition of diphenyl disulfide (PhS)2 to terminal alkynes is catalyzed by palladium complexes to give l,2-bis(phe-nylthio)alkenes (Table 3)168-172 The reaction is stereoselective, affording the (Z)-adducts as the major isomer. A rhodium(i) catalyst system works well for less reactive aliphatic disulfides.173 Bis(triisopropylsilyl) disulfide adds to alkynes to give (Z)-l,2-bis(silylsulfanyl)alkenes, which allows further transformations of the silyl group to occur with various electrophiles.174,175 Diphenyl diselenide also undergoes the 1,2-addition to terminal alkynes in the presence of palladium catalysts.176... 

The hydride route involves the initial reaction with hydrogen followed by coordination of the substrate the well-known Wilkinson catalyst [RhCl(PPh3)3] is a representative example. A second possible route is the alkene (or unsaturated) route which involves an initial coordination of the substrate followed by reaction with hydrogen. The cationic catalyst derived from [Rh(NBD)(DIPHOS)]+ (NBD = 2,5-norbornadiene DIPHOS = l,2-bis(diphenyl)phosphinoethane) is a well-known example. The above-mentioned rhodium catalysts will be discussed, in the detail, in the following sections. 

Excellent ee-values (up to 94%) have been obtained for the hydrogenation of various 2-substituted N-acetyl indoles with an in-situ prepared rhodium catalyst modified with the trans-chelating diphosphine (S,S)-(R,R)-2,2"-bis[l-(diphenyl-phosphino)ethyl]-1,1"-biferrocene (Scheme 16.23) [88]. A strong base was required as co-reagent to observe both high conversion (TOFs of 50-100) and en-... 

Bicyclo[2.2.1]hepta-2,5-diene-l,4-bis(diphenylphosphino)butanerhodium trifluoromethanesulfonate Rhodiura(l+), [(2,3,5,6- )-bicyclo[2.2.1]hepta-2,5-diene][l, 4-butanediylbi s[diphenyl phosphine]- ,P ]-, tri f1uoromethanesulfonate Bicyclo[2.2.l]hepta-2,5-diene-2,4-pentanedionatorhodiurn Rhodium, (2,5-norbornadiene) (2,4-pentanedionato)- (8) Rhodium, [(2,3,5,6- )-bicyclo[2.2.l]hepta-2,5-diene] (2,4-pentanedionato-0,0 )- (9) (32354-50-0) Trimethylsilyl trifluoromethanesulfonate Methanesulfonic acid, trifluoro-, trimethylsilyl ester (8,9) (27607-77-8)... 

Symmetric alkenediols undergo a hydroformylation reaction to give perhydrofuro[2,3-, ]pyrans in the presence of a rhodium catalyst. The reaction proceeds in high yields, except in the case of the l,6-diphenyl-3-hexene-l,6-diol (40%) (Equation 19) <2002OL289>. 

The reaction of bis-phenylpropargyl ether (321) with tris(triphenylphosphine)rhodium chloride in benzene or toluene led to the formation of the unusual organometallic compound (322), which can be viewed as a derivative of an oxygen-rhodium pentalene system. Reaction of the rhodium complex (322) with sulfur leads to the corresponding 4,6-diphenyl-l,3-dihydro[3,4-c]furan (323). The selenium and tellurium analogs (324) and (325) were made in a similar manner (Scheme 111) (76LA1448). 

Ethyl 3,3-Diphenyl-2-propenoate. In the presence of either Co2(CO)8 or rhodium this ester leads only to the hydrogenated product (16) ... 

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