Fig. 1: Transformations involving difluorocarbene.

a Free difluorocarbene-involved reactions; b Pd-catalyzed difluorocarbene transfer via [Pd] = CF₂; c Cu-catalyzed difluorocarbene transfer via [Cu] = CF₂; d This work: Cu-catalyzed multi-component reactions via [Cu] = CF₂ as carbonyl source.