Copper-Catalyzed Hydroamination of Oxa- and Azabenzonorbornadienes with Pyrazoles

An efficient and highly chemo- and stereoselective copper-catalyzed hydroamination of oxa- and azabenzonorbornadienes with various pyrazole derivatives is described. This catalytic process is promoted by the presence of N-heterocyclic carbene ligands and KOt-Bu under mild and simple reaction conditions, and allows for the direct synthesis of new and versatile functionalized oxa(aza)benzonorbornyl pyrazoles starting from readily available oxa(aza)bicyclic alkenes. The synthetic utility of this method was demonstrated by the transformation of the obtained products into pyrazolyl-substituted naphthalenes.