Abstract Cyclopropylidenecycloalkanes, which are highly strained methylenecyclopropane (MCPs) containing a cycloalkane moiety, react with carbon dioxide smoothly to give the corresponding five-membered lactone derivatives in moderate to good yields through a cyclopropane ring-opening process in the presence of Pd 0 catalyst and PCy 3 upon heating under 40 atm of CO 2. The relative configuration of the major diastereomers has been ...
