Kinetic studies of the pyrolyses of 1- and 2-naphthyl azides reveal neighbouring
group participation by nitro and phenylazo
substituents. The acceleration observed in 1-nitro-2-naphthyl azide, 1-phenylazo-2-naphthyl
azide, and 2-nitro-1-naphthyl azide is 1730-, 211-, and 23.6-fold,
respectively, in nitrobenzene solution at 120�. These effects are all
smaller than that of the 2-nitro group in phenyl azide (3370-fold), which is
ascribed to the steric effect of the peri hydrogen at
C8 in naphthyl azides. The sizes of these
neighbouring group effects correlate with the success of oxidative cyclization
of ortho-substituted naphthylamines with (diacetoxyiodo)benzene.