Copper(I)-Catalyzed Conjugate Addition/Enantioselective Protonation with Selenols and α-Substituted α,β-Unsaturated...

Herein, a copper(I)-catalyzed asymmetric conjugate addition/protonation with selenols and α-substituted α,β-unsaturated thioamides is disclosed, which affords a series of chiral selenides in high to excellent enantioselectivity. As for both selenols and α-substituted α,β-unsaturated thioamides, the reaction enjoys broad substrate scopes. The present catalytic system is also successfully applied to asymmetric selenation of β-substituted α,β-unsaturated thioamides. A [Cu-(R,R_P )-TANIAPHOS]-SePh species is characterized by its ⁷⁷ Se NMR spectra, which gives a chemical shift at δ 462 ppm. Moreover, a {[Cu-(R)-TOL-BINAP]-SePh}₂ species is characterized by X-ray analysis, which confirms the formation of Cu-Se bond in the reaction. Finally, the transformations of the thioamide group to amine and thioester are demonstrated to be straightforward.