A convenient synthesis of alpha-methylene-gamma-butyrolactones from allenyl carbonyl units mediated by Mo(CO)6 through intramolecular cyclocarbonylation.

A novel procedure for the synthesis of cis-fused bicyclic alpha-methylene-gamma-butyrolactones from allenyl carbonyl functionalities via the molybdenum-mediated cyclocarbonylation is described. The use of Mo(CO)(6) with DMSO to promote reaction results in an efficient and convenient protocol through the three-component assembly in high yields.