Catalytic Asymmetric Alkynylation of C1‐Substituted C,N‐Cyclic Azomethine Imines by CuI/Chiral Brønsted Acid Co‐Catalyst

It all adds up: The title reaction was developed for the synthesis of chiral tetrahydroisoquinoline derivatives with a tetrasubstituted carbon center at the C1-position (see scheme, Bz=benzoyl, pybox=2,6-bis(2-oxazolinyl)pyridine). The reaction was facilitated effectively by the co-catalyst system composed of copper(I)/Ph-pybox and an axially chiral dicarboxylic acid.