Asymmetric Mannich Synthesis of α‑Amino Esters by Anion-Binding Catalysis

We
report a scalable, one-pot Mannich route to enantioenriched
α-amino esters by direct reaction of α-chloroglycine ester
as a practical imino ester surrogate. The reaction is promoted by
a chiral aminothiourea, which is proposed to operate cooperatively
by generating an iminium ion by chloride abstraction and an enolate
by deprotonation, followed by highly stereoselective C–C bond
formation between both reactive intermediates associated non-covalently
within the catalyst framework.