Application of Rh(I)-catalyzed C-H bond activation to the ring opening of 2-cycloalkenones in the presence of amines.

[reaction: see text]. Herein described is the application of the Rh(I)-catalyzed C-H bond activation to the ring-opening of 2-cycloalkenones in the presence of cyclohexylamine. This reaction includes the C-C double bond cleavage of 2-cycloalkenones through the conjugate addition of cyclohexylamine followed by the retro-Mannich-type fragmentation. The resulting ring-opened intermediates subsequently underwent either chelation-assisted hydroacylation to afford a ring-opened dicarbonyl compound or beta-alkylation via a ring contraction.