New Carbonylations by Means of Transition Metal Catalysts

New homogeneous mixed metal catalyst systems for the synthesis of N-acyl-α-amino acids di rectly from allylic alcohols, oxiranes or fluoro-olefins are described. The new catalytic processes include (i) the isomerization-amidocarbonylation of allylic alcohols catalyzed by Co₂(CO)₈ - Group VIII transition metal complex combinations, (ii) the isomerization-amidocarbonylation of oxiranes promoted by Co₂(CO)₈ - Lewis acid systems, and (iii) the hydroformylation-amidocarbonylation of fluoro-olefins catalyzed by Co₂(CO)₈-rhodium carbonyl systems which proceeds with excellent regioselectivity. It is found that the hydroformylation-amidocarbonylation process includes a unique Co-Rh mixed metal complex, CoRh(CO)₇, as an active catalyst species. New amide-directed hydrocarbonylations of allylic and homoallylic amides catalyzed by rhodium complexes, Co₂Rh₂(CO)₁₂, and Co₂(CO)₈, which give a variety of monocyclic and bicyclic nitrogen-heterocycles are described. A novel rhodium-catalyzed sequential double carbonylation process was developed. Possible mechanisms of these novel carbonylation processes are discussed, including a detailed mechanistic study on the catalysis of CoRh(CO)₇.