NEW CARBONYLATIONS CATALYZED BY TRANSITION-METAL COMPLEXES

The Rh-catalyzed hydroformylation of N-allylamides gives isoaldehyde with good regioselectivity through chelation control. The Rh- and Co2Rh2(CO)12-catalyzed reactions of an N-methallylamide give a novel double carbonylation product and a pyrrolidine, respectively. These reactions are successfully applied to homoallylic systems to generate the corresponding azabicyclo[4.n.0]alkenes and alkanes. Intramolecular amidocarbonylation of 3-butenamide catalyzed by a Rh complex with excess phosphine ligands gives 3,4-dihydro-2-pyridone. The same reaction with excess P(OPh)3 affords a unique heterodimer selectively. The reaction of 4-pentenamide gives 5-methyl-3,4-dihydro-2-pyridone exclusively, regardless of rhodium catalysts used. Reactions of hydrosilanes with 1-hexyne catalyzed by Co2Rh2(CO)12 and Rh4(CO)12 at 25-degrees-C under CO give (Z)-1-silyl-2-formyl-1-hexenes, which are the products of ''silylformylation''. Novel Rh-Co complexes, (R3Si)2Rh(CO)n-Co(CO)4 and RhCo(n-Bu-C=CH)-(CO)5, are found to be important catalyst species for the reaction catalyzed by Co2Rh2(CO)12. The catalytic cycle of the reaction is proposed.