A novel one-pot synthesis of isomeric naphtho[1,2-d]isoxazole 2-oxide and naphtho[1,8-de][1,2]oxazine ring systems. A case of simultaneous o- and peri-cyclisation in naphthalene

2-Hydroxy-1-naphthaldehyde oxime 1 undergoes a one-pot o- and peri-oxidative cyclisation with lead(IV) acetate to give the isomeric naphtho[1,2-d]isoxazole 2-oxide 2 and naphtho[1,8-de][1,2]oxazine 3. A common o-nitroso quinonemethide intermediate is invoked for both isomers.