Highly efficient construction of bisspirooxindoles containing vicinal spirocenters through an organocatalytic modified Feist-Bénary reaction

Abstract

We have developed an organocatalytic modified Feist-Bénary reaction of cyclic dicarbonyl compounds, isatins and cyclic α-bromo dicarbonyl compounds. This method affords bisspirooxindole-fused dihydrofurans containing two vicinal spiro centers. To the best of our knowledge, employing cyclic α-halo dicarbonyl compounds for the synthesis of bisspirooxindole-fused dihydrofurans has not been previously reported. Crowded spaces! An organocatalytic modified Feist-Bénary reaction of cyclic dicarbonyl compounds, isatins, and cyclic α-bromo dicarbonyls was developed. This method affords bisspirooxindole-fused dihydrofurans containing two vicinal spiro centers (see scheme; DBU=1,8-diazabicyclo[5.4.0]undec-7-ene). Employing cyclic α-halo dicarbonyl compounds for the synthesis of bisspirooxindole-fused dihydrofurans has not been previously reported. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.