Synthesis of (4S,5R)-(–)-4-methyl-5-phenyloxazolidine-2-selone: a chiral auxiliary reagent capable of detecting the enantiomers of (R,S)-lipoic acid by 77Se nuclear magnetic resonance spectroscopy

Abstract

(4S,5R)-(–)-4-Methyl-5-phenyloxazolidine-2-selone was constructed in 5 steps on the 10-gram scale. ⁷⁷Se NMR spectroscropic studies revealed that this selone served as a remarkably sensitive chiral auxiliary agent which readily distinguished the selone-coupled (R,S)-lipoic acid (Δδ 0.119 ppm), even though its chiral centre was separated by 8 bonds from the observed nucleus.