HYDROFORMYLATION OF 1-ARYL-1-(2-PYRIDYL)ETHENES CATALYZED BY RHODIUM COMPLEXES

The hydroformylation of 1-aryl-1-(2-pyridyl) ethenes 1 can be accompli shed in good yield (85%) using HRh(CO) (PPh(3))(3) with rather high ca talyst to substrate molar ratios (1/80) under standard conditions. Oth er cobalt, platinum and rhodium complexes exhibit lower catalytic acti vity towards hydroformylation, the hydrogenation of the substrate bein g in most cases the main reaction. The formation of the more branched aldehyde 3 occurs in the presence of HRh(CO)(PPh(3))(3) regiospecifica lly. The formation of the complex 9 from [Rh(CO)(2)Cl](2) and olefin 1 a, in which only the pyridine nitrogen is coordinated to the metal, en lightens on the role played by the heteroatom in determining both chem o- and regioselectivity of the reaction.