Natural (2S, 3R)-3-amino-2-hydroxy-5-methylhexanoic acid is synthesized in 53-5570 yield (referred to (-1-8-phenylmenthol used as chiral auxiliary) by condensation of 1-nitro-3- methylbutane on (-)-8-phenylmenthol glyoxylate hydrate using KF as a mild base. With a large excess of KF in THF it has been possible to increase the diastereoselectivity of the nitro aldol condensation (up to I/II/III/IV= 77/13/10/0). ua
