Enzyme-Inspired Axially Chiral Pyridoxamines Armed with a Cooperative Lateral Amine Chain for Enantioselective Biomimetic Transamination

Enzymatic transamination is catalyzed
by pyridoxal/pyridoxamine,
and it involves remarkable cooperative catalysis of a Lys residue
in the transaminase. Inspired by transaminases, we developed a class
of axially chiral pyridoxamines 11 bearing a lateral
amine arm. The pyridoxamines exhibited high catalytic activity and
excellent enantioselectivity in asymmetric transamination of α-keto
acids, to give various α-amino acids in 67–99% yields
with 83–94% ee’s. The lateral amine arm likely participates
in cooperative catalysis as the Lys residue does in biological transamination
and has an important impact on the transamination in terms of activity
and enantioselectivity.