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 α, β‐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 γ‐lactone derivatives. Simple ketones were not applicable, but ketones having a C?O or C?N group at the α‐position served as a good substrate. These reactions could be extended to carbonylative cycloaddition of the corresponding imines leading to γ‐butyrolactam derivatives. The 4 + 1] carbonylative addition of α,β‐unsaturated imines leading to unsaturated γ‐lactams was achieved with Ru₃(CO)₁₂. © 2008 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 8: 201–212; 2008: Published online in Wiley InterScience ( www.interscience.wiley.com ) DOI 10.1002/tcr.20149