Enantioselective Coupling of Nitroesters and Alkynes
By using Rh-H catalysis, we couple α-nitroesters and alkynes to prepare α-amino acid surrogates. This atom-economical strategy generates two contiguous stereocenters, with high enantio- and diastereocontrol. In this transformation, the alkyne undergoes isomerization to generate a Rh(III)-π-allyl electrophile, which is trapped by an α-nitroester nucleophile. A subsequent reduction with In powder transforms the allylic α-nitroesters to the corresponding α,α- disubstituted α-amino esters.