One-Pot Cascade Transformations of Zinc Trifluorodiazoethylide and α,β-Unsaturated Enones: Access to Trifluoromethylated Polycyclic Pyrazolines

One-pot cascade transformations are developed that involve [3 + 2] cycloaddition/Michael/aldol and [3 + 2] cycloaddition/double 1,2-addition reactions of zinc trifluorodiazoethylide with various α,β-unsaturated enones. The protocol provides straightforward access to trifluoromethyl-substituted polycyclic pyrazolines with high chemo-, regio-, and diastereoselectivity