Palladium(II)-catalyzed tandem annulation reaction of o-alkynylbenzoates with methyl vinyl ketone for the synthesis of isocoumarins

A palladium(II)-catalyzed highly regioselective tandem reactions of o-alkynylbenzoates with methyl vinyl ketone for the synthesis of isocoumarins was developed. It is a convenient, mild and environmentally benign reaction with moderate to high yield. The reaction is initiated by the Pd(II) species and regenerate the Pd(II) species to complete the catalytic cycle without the necessity of a redox system.     

Approach to highly functionalized oxazolones by a Pd-catalyzed cyclization of N-alkynyl tert-butyloxycarbamates

A mild and operationally simple approach to highly functionalized oxazolones has been developed, which involves an intramolecular oxypalladation of N-alkynyl tert-butyloxycarbamates, followed by either protonolysis of the alkenyl C-Pd bond to afford 3,5-disubstituted oxazolones or allylation with allyl halides in the presence of Ag₂CO₃ to generate 3,4,5-trisubstituted oxazolones, respectively.