Activation of a Cyclobutanone Carbon–Carbon Bond over an Aldehyde Carbon–Hydrogen Bond in the Rhodium-catalyzed Decarbonylation

A rhodium(I)–N-heterocyclic carbene complex achieved a high-yield decarbonylation reaction of cyclobutanones to selectively afford cyclopropanes. With this catalyst, a cyclobutanone having an aldehyde moiety underwent chemoselective decarbonylation of the ketonic carbonyl group with the aldehydic carbonyl group left intact.