Kinetic Resolution of α‑Tertiary Propargylic Amines through Asymmetric Remote Aminations of Anilines

A practical
method for kinetic resolution of α-tertiary propargylic
amines has been achieved via asymmetric remote aminations of anilines
with azodicarboxylates enabled by chiral phosphoric acid catalysis.
A broad range of aryl and alkyl groups at the α-position, as
well as the substituted alkynyl and N-aryl groups
were well tolerated in these reactions, providing high kinetic resolution
performances (with an s-factor up to 111). In addition,
the α-tertiary amines bearing an α-CN group (the Strecker
reaction product) could be kinetically resolved with excellent stereoselectivity
as well under the same reaction conditions. Fruitful transformations
of the chiral amination products and the recovered propargylic amines
demonstrated the power of this method in asymmetric synthesis of α-tertiary
amines and their derivatives.