Total synthesis of symbioramide: A flexible approach for the efficient preparation of structural isomers

A concise, enantioselective total synthesis of symbioramide, starting from simple achiral compounds and racemic α-amino-β-keto ester derivatives is reported. This highly flexible strategy allowed the efficient preparation of seven structural isomers of the natural product as well. The synthesis relies on a convergent route that involves the efficient stereoselective reduction of a α-keto-β-yne ester, and the dynamic kinetic resolution of an α-amino-β-keto ester through ruthenium-mediated asymmetric hydrogenation.