Diphenyl carbonyl rhodium

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... 

P-31 NMR studies also were carried out in a similar manner on rhodium complexes of two chelating bisphosphines—bis-l,3-diphenyl-phosphinopropane and bis-l,2-diphenylphosphinoethane. These complexes were generated in solution via ligand displacement from tris(tri-phenylphosphine)rhodium carbonyl hydride. For example, one of the possible displacement products of bis-l,3-diphenylphosphinopropane (F) is a cis-chelate (G) that can undergo dissociation to yield a chelating bisphosphine complex (H) ... 

Rhodium carbonyl, Rh4(CO)I2, catalyzes the cyclocarbonylation of acetylenes with benzene to give indenones. For example 2,3-diphenyl -indenone is obtained from diphenyl acetylene and benzene in 10% yield, corresponding to a catalytic turnover of 11 (220°C, 25 bar, 7 hr)... 

Time-resolved FTIR spectra of Rh4(CO)12 subjected to 266 nm. irradiation in heptane gave evidence for the formation of two isomeric forms of Rh4(CO)n(solv).144 Vibrational assignments were made to vCO modes for gas-phase rhodium cluster carbonyls using IR multiphoton depletion spectroscopy. For Rhn(CO), vCO was at 1950 2 cm-1 (n = 6), 1960-1965 cm-1 (n = 7-11 13-20).145 TRIR data (vCO) were used to follow the formation of intrinsically chiral clusters Rh6(CO)i4(p,K2-PX), where PX = bidentate bridging ligands diphenyl(benzothienyl)phosphine and related systems.146... 

With alkynes hydrocarbonylative coupling leads to unsaturated ketones with exclusive cis addition of hydrogen and the acyl group. Thus, rhodium carbonyl catalyzed carbonylation of acetylenes and ethene with carbon monoxide and hydrogen stereospecifically leads to a./l-un-saturated ethyl ketones by cross hydrocarbonylation4- 5, e.g., diphenylacetylene with ethene in the presence of Rh4(CO)l3 gives ( )-1.2-diphenyl-l-penten-3-one in 91 % yield5. 

C3 7H2 5Fe205PS, Dicarbonyl (triphenyIphosphine) iron-/Li (1,2-diphenyl-ethylene-1 -thiolato-2-yl)-tricarbonyl iron, 44B, 727 C37H3oC10P2Rh, trans-Carbonyl-chloro-bis(triphenylphosphine)rhodium-(I), 45B, 894... 

NOCbHb, Benzoyl isocyanide, chromium complex, 26 32, 34, 35 NOPC23H20, Benzamide, 2-(diphenyl-phosphino)-Al-phenyl-, 27 324 NOI bsHss) nzamide, N-[2-(diphenyl-phosphino)phenyl]-, 27 323 NObCbHb, 4-Pyridinecarboxylic acid, rhodium complex, 27 292 N02P2C3 H33, Phosphorus(l -t-), /i-nitrido-bis(triphenyl)-, acetate, 27 296 N03P2RhC25H4B, Rhodium(I), carbonyl(4-pyridinecarboxylato)bis(triisopropyl-phosphine)-, 27 292... 

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