Pt0-complexes as catalyst precursors for homogeneous carboncarbon and carbonoxygen double bond hydrogenation

Complexes of the type Pt(C2H4) (chelating diphosphine) in the presence of methanesulfonic acid have been found to be active catalysts for the hydrogenation of carboncarbon and carbonoxygen double bonds. The terminal olefin reduction is accompanied by extensive substrate isomerization, and the resulting internal alkenes undergo very little hydrogenation. The highest catalyst activity is displayed in the hydrogenation of olefinic substrates bearing an electron-withdrawing group. The catalytic system is also active in the hydrogenation of aldehydes to the corresponding alcohols, whereas it is almost inactive in hydrogenation of ketones. The results obtained in the asymmetric hydrogenation of prochiral olefinic substrates allow formulation of a possible intermediate in the catalytic cycle. © 1990.