Ruthenium-catalyzed carbonylative cycloaddition reactions involving carbonyl and imino groups as assembling units.
This paper describes carbonylative cycloaddition reactions catalyzed by Ru3(CO)12. Ru3(CO)12 was found to catalyze an intramolecular Pauson-Khand-type reaction. Carbonylative cycloaddition reactions involving a carbonyl group in aldehydes, ketones, and esters as a two-atom assembling unit were also achieved in the presence of Ru3(CO)12 as the catalyst. The reaction of 5-hexyn-1-al and 6-heptyn-1-al derivatives with CO in the presence of Ru3(CO)12 resulted in cyclocarbonylation from which bicyclic alpha, beta-unsaturated lactones were obtained. Intermolecular [2 + 2 + 1] carbonylative cycloaddition of alkenes, ketones, and CO was also catalyzed by Ru3(CO)12 as the catalyst to give saturated gamma-lactone derivatives. Simple ketones were not applicable, but ketones having a C==O or C==N group at the alpha-position served as a good substrate. These reactions could be extended to carbonylative cycloaddition of the corresponding imines leading to gamma-butyrolactam derivatives. The [4 + 1] carbonylative addition of alpha,beta-unsaturated imines leading to unsaturated gamma-lactams was achieved with Ru3(CO)12.
Chatani
Naoto
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Department of Applied Chemistry, Faculty of Engineering, Osaka University, Suita, Osaka 565-0871, Japan.