3-NITRO-2<i>H</i>-CHROMENES IN [3+2] CYCLOADDITION REACTION WITH AZOMETHINE YLIDES DERIVED FROM <i>N</i>-UNSUBSTITUTED α-AMINO ACIDS AND ISATINS: REGIO- AND STEREOSELECTIVE SYNTHESIS OF SPIROCHROMENO[3,4-<i>c</i>]PYRROLIDINES

Abstract

A regio- and stereoselective method was developed for the synthesis of tetrahydro-4H-spiro[chromeno[3,4-c]pyrrole-1,3'-indolin]-2'-ones in 72−96% yields, using a three-component reaction of 3-nitro-2-trifluoromethyl- and 3-nitro-2-phenyl-2H-chromenes with azomethine ylides that were generated in situ from N-unsubstituted α-amino acids and isatins.