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 alpha-amino-beta-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 alpha-keto-beta-yne ester, and the dynamic kinetic resolution of an alpha-amino-beta-keto ester through ruthenium-mediated asymmetric hydrogenation.