Access to cyano-substituted pyrazolines through copper-catalyzed cascade cyanation/cyclization of unactivated olefins

A novel and efficient copper-catalyzed domino cyanation/cyclization of hydrazone-tethered unactivated olefins has been developed. A range of cyano-containing pyrazolines have been easily obtained in good yields under mild conditions. This method provides a facile, practical, and rapid access to valuable pyrazolines with the important cyano functionality, and it is amenable for gram scale synthesis. The simultaneous formation of C(sp(3))-CN and C-N bonds can be achieved in a single step.