Pd(0) or Pd(II)-catalyzed ring-opening reactions of benzylidene- and alkylidenecyclopropyl ketones and aldehydes

Pd(0) catalyzed reactions of methylenecyclopropyl carbonyl compounds afforded a convenient method for the synthesis of conjugate (E,E)-1,3-diene derivatives 2 in good to excellent yields. Moreover, we also found that Pd(II)-catalyzed reactions of methylenecyclopropyl carbonyl compounds with water gave 1,5-diketones in good to high yields via a carbene–palladium intermediate. The plausible reaction mechanisms have also been provided on the basis of control and 18O-labeling experiments.

Graphical abstractThe ring-opening reactions of methylenecyclopropyl ketones or aldehydes catalyzed by Pd(0) or Pd(II) catalyst deliver the corresponding conjugate (E,E)-1,3-dienes or 1,5-diketones in good to excellent yields, respectively.Figure optionsDownload full-size imageDownload as PowerPoint slide