"Polar addition" based approach: reagents. The reaction of NO2 gas or fuming nitric acid with alkenes delivers doubly nitrated product or mixture of nitrate esters. b, Possible competing pathways of alkene radical hydronitration. c. Optimization of reaction conditions: a survey of anomeric nitroamide 35A with precedented nitrating reagents reveals its superior reactivity, further structural optimization leads to 16 as the optimal reagent. a All reactions were performed on a 0.1 mmol scale. 1 H NMR yields were calculated using CH2Br2 as the internal standard. b 40% 23 was recovered. c 47% 23 was recovered. d 32% 23 was recovered. TMDSO, tetramethyldisiloxane; Ac2O, acetic anhydride; ND, not determined; rt, room temperature.