Asymmetric Copper-Catalyzed Propargylation of 5-Aminopyrazoles with Propargylic Acetates

Abstract An asymmetric copper-catalyzed propargylic substitution reaction of propargylic acetates with ambident 5-aminopyrazoles was developed. Under optimized conditions, the relevant products with a wide range of substrates and good functional tolerance were obtained in 51–98% yields and up to 99:1 er. A gram-scale reaction and synthetic transformations demonstrated the practicality, delivering chiral γ-aryl-substituted propargylic products with high enantioselectivity.