Full experimental details, including general information, experimental methods for ring opening reactions and rearrangement reactions, reaction optimization, mechanistic studies, Chiral studies, 1 H NMR spectra, C NMR spectra, high-resolution mass spectrometry (HRMS) and High-performance liquid chromatography (HPLC) data are available in the supplemental information for all compounds. Crystallographic data are available free of charge from the Cambridge Crystallographic Data Centre (CCDC): 2235405. Raw data are available from the corresponding author upon reasonable request. Double C-N cleavage in organic microdroplets: Imidazoline derivative 1 (1.5 mg, 5.0 mmol L -1 , 1.0 equiv) and 0.05-5 μL (0.18-18.4 equiv) of sulfuric acid (98%) were dissolved in 2 mL acetonitrile. The mixed solution was fed (15-300 μL min -1 ) into a concentric capillary (150 μm ID × 365 μm OD) of a nebulizer with dry nitrogen gas at 101.5 psi. Microdroplets were sprayed into an electrically heated glass chamber with temperature monitored by a thermocouple thermometer, and collected in a 25 mL glass beaker for 10 min (Figure ). The collected crude product was washed with saturated aqueous NaHCO3 and extracted with dichloromethane (1 mL). The organic layer was collected and filtered by a 0.22 μm filter, and appropriately diluted for yield measurements by high performance liquid chromatography (HPLC) using external standard method. The crude product from scaled reaction was purified by preparative thin-layer chromatography (PTLC) (petroleum ether / ethyl acetate = 3 : 1 ~ 1 : 1) for characterization.