Graphical abstract
Herein we report a Rh(II)-catalyzed direct and stereospecific N–H- and N–alkyl aziridination of olefins that uses hydroxylamine-O-sulfonic acids as inexpensive, readily available and nitro group-free aminating reagents. Unactivated olefins, featuring a wide range of functional groups, are converted to the corresponding N–H or N–alkyl aziridines in good to excellent yields. This operationally simple, scalable transformation proceeds efficiently at ambient temperature and is tolerant towards oxygen and trace moisture.