Recently discovered reactivity of nitrostyrenes in phosphorous acid to facilitate the diastereoselective [4 + 1]-cycloaddition of indoles in combination with unusual oxazoline ring cleavage and subsequent 1,2-alkyl shift afforded stereochemically defined 2-(3-oxoindolin-2-yl)-2-arylacetonitriles as sole products.

Highly efficient cascade involving Michael addition and Baeyer–Drewson reaction is triggered by cyanide anion and transforms ortho-nitrochalcones into 2-(3-oxoindolin-2-ylidene)acetonitriles.

An efficient and straightforward Brønsted-acid mediated cascade process was developed, involving cyclization of readily available β-ketonitriles into 2-aminofurans, and their subsequent recyclization into 2-(1H-indol-2-yl)acetamides is developed. This synthetic route opens a new avenue for an expeditious assembly of various isotryptamine derivatives for medicinal chemistry.

An acid-assisted [4 + 1]-cycloaddition of indoles with nitrostyrenes affords 4′H-spiro­[indole-3,5′-isoxazoles] in a diastereomerically pure form. Several of these spirocyclic molecules exhibit promising anticancer activity by reducing viability and inducing differentiation of neuroblastoma cells.

Indolo[3,2-c]quinolones have been efficiently synthesized via an acid-mediated, one-pot, three-component condensation of arylhydrazines, o-aminoacetophenones, and triazines or nitriles. The synthetic application of this method is showcased by the concise synthesis of isocryptolepine alkaloid and a series of its synthetic analogues with demonstrated cancer cell antiproliferative activities.

An unusual reactivity of nitrostyrenes in phosphorous acid was discovered, which permits the employment of these readily available synthons as 1,4-CCNO-dipole surrogates in a highly diastereoselective (4+1)-cycloaddition of indoles to afford 4′H-spiro[indole-3,5′-isoxazoles] in a diastereomerically pure form.

PPA-activated nitroalkanes are employed in the design of a one-pot cascade transformation involvingortho-C–H functionalization, by Beckman rearrangement, and condensation to produce benzoxazoles and benzobisoxazoles directly from phenols.

The highly efficient oxidative cyclization of 1,3-diarylsubstituted 3-cyanoketones yielded 5-hydroxy-1,5-dihydro-2H-pyrrol-2-ones.