Electrophilic reactions at single bonds. 26. Oxygenation of bicyclo[2.2.1]heptane and bicylo[2.2.2]octane with nitronium tetrafluoroborate
摘要:
Reaction of bicyclo [2.2.1]heptane (1) with nitronium tetrafluoroborate in nitroethane gives bicyclo[2.2.1]heptan-2-one (2). Bicyclo[2.2.1]heptan-2-yl nitrite (3) was observed as the intermediate of the reaction. The reaction of exo-bicyclo[2.2.1]heptan-2-ol (4) with nitrosonium tetrafluoroborate also gave 2. The reaction of 2-norbornyl cation with silver nitrite gave 2. When exo-2-bromobicyclo[2.2.1]heptane (10) reacted with silver nitrite in ether, 2 and 2-nitrobicyclo[2.2.1]heptan (8) were obtained in 1.3:1 ratio. Reaction of bicyclo[2.2.2]octane (5) with nitronium tetrafluoroborate yields upon aqueous workup bicyclo[2.2.2]octan-1-ol (6). No nitro products were observed in either of the reactions. The mechanism of the observed reactions is discussed.