Absolute configuration at the chiral nitrogen atom in optically active oxaziridines. X-Ray structure, physical properties, and thermal epimerization of (–)-(2S)– and (+)-(2R)-2-[(R)-α-methylbenzyl]-3,3-diphenyloxaziridines

Abstract

The crystal and molecular structures of (–)-(2S)- and (+)-(2R)-2-[(R)-α-methylbenzyl]-3,3-diphenyloxaziridine (2) and (3) have been determined from X-ray three-dimensional diffraction data and refined by full-matrix least-squares to R 5.1 [(2); 1 560 reflections] and 4.6%[(3); 1 285 reflections]. Thermal epimerisations have been studied by polarimetry and ¹H n.m.r. spectroscopy. The results suggest that isomerisations involve neither bond cleavage nor racemisation but only a nitrogen inversion mechanism.