(2S,3R,4S)-4-Hydroxyisoleucine, found in fenugreek, is an insulinsecretagogue molecule. Non-natural analogues of (2S,3R,4R)- and (2R,3S,4S)-4-hydroxyisoleucine were efficiently prepared by 1,3-dipolar cycloaddition reactions of chiral nitrones derived from either (−)- or (+)-menthone to alkenes. The cycloadducts, obtained via the exo-approach of the alkenes to the nitrone’s less hindered face, led