C-C Double Bond Cleavage of Linear α,β-Unsaturated Ketones

Abstract

The activation of C-H bonds by transition-metal complexes is one of the most efficient methods to form C-C bonds in organic synthesis.1 We have successfully developed a Rh(I)catalyzed C-H bond activation series using 2-amino-pyridine derivatives2 or benzylamine3 as a chelation auxiliary to induce cyclometalation.4 In the course of our studies on chelation-assisted C-H bond activation, we reported a Rh(I)catalyzed hydroiminoacylation of alkynes with allylamine derivatives5 or aldehydes,6 which was further applied to the retro-Mannich-type fragmentation of the resulting unsaturated ketimine by primary amines. Encouraged by these results, we also developed a Rh(I)-catalyzed C-H bond activation of the ring opening in 2-cycloalkenones7 and a chelation-assisted ^-alkylation of o, ^-unsaturated ketone