Hydrogenation of olefins and acetylenes

A very significant recent development in the field of catalytic hydrogenation has been the discovery that certain transition metal coordination complexes catalyze the hydrogenation of olefinic and acetylenic bonds in homogeneous solution.Of these catalysts tris-(triphenylphosphine)-chloror-hodium (131) has been studied most extensively.The mechanism of the deuteration of olefins with this catalyst is indicated by the following scheme (131 -> 135) ... 

J. A. Osborne, F. J. Jardine, J. F. Young, G. Wilkinson, The Preparation and Properties of Tris(triphenylphosphi-ne)halogenorhodium(I) and some Reactions thereof including Catalytic Homogeneous Hydrogenation of Olefins and Acetylenes and their Derivatives, J. Client Soc A. 1966,1711-1732. 

The full report of the crystal structure of Cp3Ti has appeared.1 la Diphenylacetylene reacts with CpTi(CO)2 in the cold to give the yellow monoacetylene complex Cp2Ti(CO)PhC2Ph the acetylene is readily displaced by CO and the complex is an active catalyst for the hydrogenation of olefins and acetylenes. Under more vigorous reaction conditions the metallocycle (1) is formed.12... 

One of the most fundamental examples of a surface-mediated reaction is the heterogeneous catalytic hydrogenation of olefins and acetylenes on charcoal-supported transition metals like Pd, Pt, Ni,... 

Organolanthanoide hydrides (1 11,1 8,215,221), cyclopentadienyl-ytterbium(ll) complexes (190) as well as the cocondensation products of lanthanoides with acetylenic derivatives (137,216,222) catalyze the hydrogenation of olefins and acetylenes. 

A substantial percentage of the transition metal complexes which catalyze the hydrogenation of olefins and acetylenes have a [Pg.84]

One of the earliest examples of polystyrene-bound palladium was reported by Tera-sawa and co-workers in 1975, when such a system was used for hydrogenation of olefins and acetylenes and isomerization of double bonds. However, it is not clear if the high activity exhibited by resin-bound catalysts toward hydrogenation was due to the reduced heterogeneous paUadium deposited on the resin. Pittman et al. in 1976 prepared a series of diphenylphosphinated PS-based palladium catalysts and studied their behavior... 

Osborn, J. A. Jardine, R H. Young, J. R Wilkinson, G. The preparation and properties of tris(triphenylphosphine)halogeno-rhodium(I) and some reactions thereof including catalytic homogeneous hydrogenation of olefins and acetylenes and their derivatives. /. Chem. Soc. A 1966,1711-1732. 

Grubbs and others " have reported the use of metallocenes attached to crosslinked styrene-divinylben2ene (20%) copolymers. These systems catalyze a wide variety of reactions, including reduction of dinitrogen, isomerization of olefins, hydrogenation of olefins and acetylenes, epoxidation of olefins, and isomerization of cyclodienes. 

Nagashima, H., Nakaoka, A., Tajima, S., Saito, Y, Itoh, K. Catalytic hydrogenation of olefins and acetylenes over CeoPdn. Chem. Lett. 377,1361-1364 (1992)... 

C. Homogeneous hydrogenation of olefins and acetylenes The variety of transition metal complexes which will catalyse the hydrogenation of unsaturated hydrocarbons under homogeneous conditions is exemplified in Table 30. Only two of these reactions, which have been studied in some detail, are discussed here. 

---