CARBON-MONOXIDE AS A BUILDING-BLOCK IN ORGANIC-SYNTHESIS .4. DIRECT PREPARATION OF AMINES FROM ALKENES BY AMINOMETHYLATION CATALYZED BY DINUCLEAR RHODIUM COMPLEXES

The one-pot aminomethylation reaction has been performed under low pressures of carbon monoxide and hydrogen in the presence of the complex [Rh2(mu-S(t)Bu)2(CO)2(PPh3)2]. This reaction involves the successive hydroformylation of the alkene, the condensation of the aldehyde produced in the first step with the amine, and the hydrogenation of the imine or enamine thus obtained. This last hydrogenation step is rate-determining. At 1.8 MPa, oct-1-ene was transformed with 99% conversion, giving 80% diethylnonylamine, 2% of the iso-compound and 13% methyl-2-octanal, which is more resistant to the condensation with diethylamine and further hydrogenation.