Amrutha, U.Babu, B.Prathapan, S.2026-02-052019Journal of Heterocyclic Chemistry, 2019, 56, 12, pp. 3236-32430022152Xhttps://doi.org/10.1002/jhet.3718https://idr.nitk.ac.in/handle/123456789/24262In the cycloaddition reaction between fluorenone N-aryl nitrones and 1,1-disubstituted allenes, the initially formed cycloadduct underwent facile [1,3] shift to give 1?-phenylspiro[fluorene-9,2?-pyrrolidin]-4?-ones. Although 1?-phenylspiro[fluorene-9,2?-pyrrolidin]-4?-ones are stable in solid state, a few of them underwent facile aerial oxidation in solution to give the corresponding 1?-phenylspiro[fluorene-9,2?-pyrrolidine]-4?,5?-diones in excellent overall yields. © 2019 Wiley Periodicals, Inc.articlecycloadditionoxidationsolid statesynthesisMetal free synthesis of 1-azaspiro[4.4]nonane-3-one system via reactions of nitrones with 1,1-disubstituted allenes