The reaction of the propargyl amines R1C⋮CCH(R2)NMe(R3) and thioethers R1C⋮CCH(R2)SR4 (R1= Me, n-Bu, Ph; R2 = H, Me; R3 = Me, bn; and R4 = Me, i-Pr, Ph) with Li2PdCl4 in methanol affords the air-stable five-membered palladocyclic compounds [PdC(R1)C(Cl)CH(R2)NMe(R3)(μ-Cl)]2 and [PdC(R1)C(Cl)CH(R2)SR4(μ-Cl)]2, respectively, resulting formally from the trans nucleophilic addition of the chlorine anion onto the C⋮C bond. On the other hand, alkynes with more sterically demanding groups (R1 = t-Bu or SiMe3) only form adducts of the type PdCl2(alkyne)2. Under the same reaction conditions, the terminal alkynes (R1 = H) afford analogous five-membered palladocyclic compounds in very low yields and an ill-defined mixture of organic/organometallic products. However, the treatment of these terminal alkynes with catalytic amounts of palladium(II) salts and copper dichloride in the presence of lithium chloride and water yields (2-chloroallyl)amines and thioethers in good yields.

A minilibrary of cationic N-heterocycles has been prepared and evaluated. The potential for the preparation was a result of the high versatility of palladium-mediated chemistry. The synthesis of the novel molecules was based on intramolecular quaternization of tertiary amine attached allylpalladium complexes. The steric and electronic factors of the reaction are discussed. The structures of the synthesized molecules made them candidates for precise biological and pharmaco-