Abstract N-aryl methylene benzo-fused sultams (2, 3-dihydrobenzo [d] isothiazole 1, 1- dioxides) underwent [3+ 2] cycloaddition with benzonitrile oxide to give 5-spiro isoxazoline adducts with complete regioselectivity. Steric hindrance by atropisomerism around the N- aryl bond induced facial selectivity in these cycloadditions.
