Ruthenium- and Copper-Catalyzed Propargylic Substitution Reactions of Propargylic Alcohol Derivatives with Hydrazones.

Ruthenium- and copper-catalyzed propargylic substitution reactions of propargylic alcohol derivatives with  N -monosubstituted hydrazones as ambident nucleophiles are achieved where  N -monosubstituted hydrazones exhibit impressive different reactivities dependent on different catalytic systems, behaving as carbon-centered nucleophiles to give the corresponding propargylic alkylated products in ruthenium catalysis, or as nitrogen-centered nucleophiles to afford the corresponding propargylic aminated products in copper catalysis, respectively.  DFT calculations are carried out to investigate detailed reaction pathways of these two systems.  Further transformation of propargylic substituted products affords the corresponding multisubstituted pyrazoles as cyclization products in good to high yields.