Desilylative Nitration of Alkyl- and Allylsilanes with Nitronium Salts

Desilylative nitration of methyl- and ethylsilanes with nitronium tetrafluoroborate in sulfolane solution gives nitromethane and nitroethane, respectively. Higher alkylsilanes are also nitrated, but the reactions are followed by HNO₂ elimination. The method represents the first successful nitrodesilylations at saturated carbon. Allylsilanes react cleanly with NO₂BF₄ in methylene chloride solution to give nitropropenes in good to excellent yield. These reactions, however, involve initial attack by NO₂⁺ on the allylic π-system followed by fluoride-induced trimethylsilyl elimination and not direct desilylative nitration at saturated carbon. 1-(Trimethylsilyl)but-2-ene gives exclusive secondary 3-nitrobut-1-ene and not the primary direct nitrodesilylation product 1-nitrobut-2-ene.