Synthesis of All the Diastereomers of 2‐Amino‐3‐hydroxy‐4,5‐dimethylhexanoic Acid

Herein, we describe an efficient stereoselective synthesis of all the diastereomers of 2-amino-3-hydroxy-4,5-dimethylhexanoic acid. The γ-branched carbon skeleton was set up by reaction of Garner's aldehyde with 2-lithio-3-methyl-2-butene. Hydrogenation (Pd/C catalyst) of the tetrasubstituted olefin proceeded smoothly with acceptable stereoselectivity, depending on the diastereomer hydrogenated. The final compounds were then obtained in 12–18 % overall yield through intramolecular cyclization, Jones oxidation, and hydrolysis in 5–7 steps from Garner's aldehyde.