SYNTHESIS OF ETA-3-ALLYL-PD COMPLEXES AND SUBSEQUENT FORMATION OF N-HETEROCYCLES VIA THE REACTION OF A CYCLOMETALATED COMPOUND WITH CONJUGATED DIENES

The Pd-C bond of the cyclopalladated derivative of dimethylaminomethyl ferrocene (1) is fairly reactive to insertion of conjugated dienes suc h as 1,3-butadiene, isoprene, 2,3-dimethylbutadiene or 1,3-cyclohexadi ene. This reaction affords organopalladium complexes containing an eta 3-allyl-Pd moiety where the NMe2 unit of the starting material is stil l intramolecularly coordinated to Pd. These complexes are stable in so lution but in MeOH in the presence of PPh3, reductive elimination of P d is observed. This occurs whilst a nucleophilic intramolecular additi on of the NMe2 group to the allylic fragment takes place, affording si x-, seven- or eight-membered heterocyclic compounds. The importance of the steric effects of the substituents on the butenyl chain upon the course of the reaction has been investigated.