Reactions of palladium(0) olefin complexes stabilized by some different hetero- and homo-ditopic spectator ligands with propargyl halides

Several new allenyl and propargyl complexes have been obtained by oxidative addition with propargyl chlorides of palladium (0) olefin complexes stabilized by N−N, P−P, N−P, N−S. and N−C homo− and hetero−ditopic spectator ligands. The oxidative addition of some of the isolated palladium(0) olefin derivatives with 3−chloro−1−propyne and 3−chloro−1− phenyl−propyne has been investigated and the ensuing tautomeric mixtures bearing propargyl and allenyl fragmenst η1− coordinated isolated. As a consequence of a detailed kinetic study, we have analyzed the influence of the electronic and steric parameters of the involved reactants and hypothesized the mechanism of reaction. The tautomeric rearrangement of one allenyl isomer into its propargyl counterpart was also investigated and in this case the complete determination of all the rate constants involved has been obtained. Beside these studies, two very rare η3−propargyl palladium derivatives have been isolated and characterized.