Cu^II/TEMPO‐Catalyzed Enantioselective C(sp³)–H Alkynylation of Tertiary Cyclic Amines through Shono‐Type Oxidation

Abstract

A novel strategy for asymmetric Shono-type oxidative cross-coupling has been developed by merging copper catalysis and electrochemistry, affording C1-alkynylated tetrahydroisoquinolines with good to excellent enantioselectivity. The use of TEMPO as a co-catalytic redox mediator is crucial not only for oxidizing a tetrahydroisoquinoline to an iminium ion species but also for decreasing the oxidation potential of the reaction. A novel bisoxazoline ligand is also reported.