Aziridines, recognized as the smallest nitrogen-containing heterocyclic compounds, are a "privileged scaffold" extensively found in natural products and pharmaceuticals, such as Mitomycin A (antitumor agents), Azicemicin A (antimicrobial antibiotic) and FR-66979 (antitumor antibiotic) (Scheme 1a). 1-6 Notably, as a crucial building block, various methods for synthesizing aziridines have emerged. 5-10 These primarily include 1) intramolecular cyclization of amino or azido alcohols. 2) addition of carbene equivalent to imine. 8 3) addition of nitrene equivalent to olefin. 9 Transforming simple olefins into highvalue-added aziridines, given that the significance of olefins as a chemical feedstock, represents a challenging and significant task. However, most of the research studies on alkene aziridination have predominantly focused on the syntheses of activated aziridination compounds, where R is an electron-withdrawing group (Scheme 1b, R = EWG). 7,9- 10 Typically, these reactions generally require transition metal catalysis. Conversely, the synthesis of free N-H aziridines has garnered relatively less attention, probably due to the scarcity of suitable nitrene precursors and approaches. 11-16 In a seminal study in 2014, the Kürti, Falck, and Ess group reported a rhodium-catalyzed N-H aziridination of alkenes utilizing O- hydroxylamines (DPHs) as the aminating reagent (Scheme 1c, left). 13 They later extended this approach to include both N-H-and N-alkyl aziridination of olefins, using hydroxylamine-O-sulfonic acids (HOSA) as nitrene precursors alongside Rhodium(II) dimer catalyst and pyridine as base. 14a Subsequently, Kürti's group has advanced the field by demonstrating enantioselective aziridination using commercially available (+)-3-(trifluoroacetyl)camphor as a chiral catalyst, producing aziridines from simple alkenes through transient oxaziridines formed in situ from HOSA and electron-deficient ketones aziridination of alkenes, (Scheme 1c, middle). 15 Most recently, the Jat and Tiwari groups also reported a metal-free intermolecular N-H using Scheme 1. Overview of aziridines. TsONHBoc as the aminating agent (Scheme 1c, right). 16a However, TsONHBoc needs to be prepared through 2steps with a lower atomic economy. Despite these advances, there is still room for developing new practical reaction systems for the synthesis of free N-H aziridines, especially from simple alkenes and commercially available inexpensive aminating agents, which remains challenging. Herein, we presented a practical methodology for intermolecular alkene aziridination using HOSA as the aminating agent, pyridine or piperidine as the base, and HFIP as the solvent (Scheme 1d). This method highlights the advantages of straightforward operation, mild reaction conditions, and excellent compatibility with various functional groups. Furthermore, it can be scaled up to gram-scale for the synthesis of aziridines.