A one-pot route for the synthesis of spiro-isobenzofuran compounds was developed via the condensation reaction of ninhydrin with 4-amino-1,2-naphthoquinones or 2-amino-1,4-naphthoquinones in acetic acid followed by the oxidative cleavage of the corresponding vicinal diols at room temperature. Various derivatives of spiro[benzo[ g ]indole-2,1′-isobenzofuran]-3,3′,4,5(1 H ) tetraones and spiro[benzo[ f ]pyrrolo[2,3- h ]quinoxaline-2,1′-isobenzofuran]-3,3′(1 H )-diones were synthesized in good to high yields. Moreover, further condensation of spiro[benzo[ g ]indole-2,1′-isobenzofuran]-3,3′,4,5(1 H )-tetraones with 1,2-diamines resulted in the new spiro-isobenzofuran compounds having phenazine rings in high yields.

One-pot metal-free periodic acid-mediated syntheses of azocine rings with high yields under mild reaction conditions via the addition reactions of enaminones and acenaphthoquinone.

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Various new alkyl 1-naphthoates bearing quinoline, pyranone and cyclohexenone moieties were successfully synthesized by a one-pot sequential addition/oxidation process.