Enantiomerically pure cyclic nitrones, readily available via electrophilic hydroxyaminations of N-acylsultams, serve as key intermediates in the syntheses of optically pure (-)-allosedamine, (-)-pinidine, (-)-coniine, (-)-solenopsin-A, (-)-2-heptylpyrrolidine, (-)-solenopsis fugax venom and (-)-xenovenine. This work also features a new deoxygenative decarboxylation of N-hydroxylamines carrying an acyl substituent at C(α). N-4-Alkenylhydroxylamine cyclizations proceed in a suprafacial manner, consistent with a retro-Cope elimination pathway. This reaction is strategically employed in short and efficient syntheses of (±)-α-lycorane and the enantiomerically pure alkaloid (+)-trianthine.