REACTIVITY OF CYCLOPALLADATED COMPOUNDS .26. INTRAMOLECULAR CARBON CARBON VS CARBON NITROGEN BOND FORMATION IN AN ORGANOPALLADIUM COMPOUND

The reaction of the cyclopalladated compound of the 1,2,3,4-tetrahydro-1-(dimethylamino)naphthalene ligand, 2, with 1 equiv of ethyl 3-phenylpropynoate leads to insertion of one alkyne into the Pd-C bond of 2. The depalladation of this compound at reflux chlorobenzene temperature results in the synthesis of organic heterocyclic compounds. In the case of an iodated derivative the complete demethylation of the NMe2 group is observed concomitantly with the C-N bond formation. The reaction of 2 with 2 equiv of diphenylacetylene leads to insertion of two alkynes into the Pd-C bond. The depalladation of this latter compound affords organic products containing a fulvene or a naphthyl ring via annulation of two phenyl units of the alkyne and an indolizinium derivative generated through intramolecular formation of a C-N bond by nucleophilic addition of an NMe2 group to a polysubstituted alkene unit eta-2-bonded to Pd.