Diastereoselective synthesis of ß-heteroaryl syn-α-methyl-ß-amino acid derivatives via a double chiral auxiliary approach.

ABSTRACT

The addition of the SuperQuat enolate to five- and six-membered heterocyclic tert-butyl sulfinimines led to a high syn-selectivity of up to 991 in good to excellent yields. The reaction is tentatively proposed to proceed through an open-chain transition state with the presence of an α-heteroatom on the sulfinimine leading to high diastereoselectivities. The adducts were derivatized to ß-amino esters and amides in a facile manner.