Some cationic η3-propargylpalladium complexes were prepared upon treatment of the corresponding η1-propargyl- or η1-allenylbis(triphenylphosphine)palladium(II) chloride with Ag[BF4] or Na[BPh4]. The effectiveness of the latter reagent suggests that a η1-propargyl- or η1-allenyl(chloro)palladium complex equilibrates with a cationic η3-propargylpalladium complex with the liberation of a Cl− ligand. A
phosphane, which is employed as the palladium atom’s ligand, and the solvent have a remarkable effect on this reaction. We found that the optimum conditions for the reaction are those using a bidentate phosphane ligand (dppe) in a polar solvent (DMF). Compound 1a reacted smoothly with both aromatic (PhSH) and secondary thiols (CySH) in high yields. The reactions with thiols bearing functional groups (OH or
γ-disubstituted propargylic tosylates was achieved by using metallic barium as the promoter. Various propargylated hydrazines (α-adducts) were exclusively synthesized from the corresponding propargylic tosylates and azobenzenes (diaryldiazenes). The thus-obtained propargylic hydrazines were further efficiently converted into propargylicamines by reductive N–N bond cleavage. Benzidine rearrangement of the propargylic