NEW SYNTHESIS OF ETHYL 2,3-DIHYDRO-1H-PYRROLO[1,2-A]INDOLE-9-CARBOXYLATES VIA APPARENT 1-AZA-1'-OXA [3,3]SIGMATROPIC REARRANGEMENT

The reaction of N-arylhydroxylamines (3a-f) with ethyl 6-oxo-2-hexynoate (4) and sodium cyanoborohydride affords a series of tricyclic ethyl 2, 3-dihydro-lHpyrrolo[l, 2-a]indole-9-carboxylates (5a-g) in 25-68% yield via apparent l-aza-l'-oxa [3, 3]sigmatropic rearrangements of N-aryl-O-vinylhydroxylamine intermediates (e.g., 7). © 1979, American Chemical Society. All rights reserved.