D-Nitration with nitronium salts

Nitronium tetrafluoroborate is a very efficient reagent for the D-nitration of alcohols and glycols containing both primary and secondary hydroxy functionality (Equation 3.7). Yields of nitrate ester are high and frequently quantitative. 0-Nitration with nitronium salts produces a strong acid and so an acid-binding agent should be present for acid sensitive substrates. 

Commercially available nitronium tetrafluoroborate contains between 5 and 15 % nitroso-nium tetrafluoroborate and is difficult to purify due to its poor solubility in many organic solvents. The synthesis of high purity nitronium tetrafluoroborate has been described. Nitronium hexafluorophosphate is less widely available but can be purified by recrystallization from nitromethane.  

Allylic and homoallylic alcohols are particularly susceptible to oxidation and dehydration. Hiskey and Oxley successfully nitrated both allyl alcohol and l-buten-4-ol with nitronium tetrafluoroborate in diethyl ether at -71 °C. 

---