The crystal structures of (Z)-dimethyl 3-methoxycarbonylmethyl-11-methyl-2-oxo-1,4,5,6,6a,11-hexahydrofuro [2′,3′:2,3]cyclohexa[1,2-b]-indol-6a-ylfumarate, (E)-dimethyl-3-methoxycarbonylmethyl-12-methyl-2-oxo-4,5,6,7,7a,12-hexahydro-1H-furo[2′,3′:2,3]cyclohepta-[1,2-b]indol-7a-ylmaleate, and trimethyl 6-bromo-9-methyl-2-oxo-1,2,3,9a-tetrahydro-3,9a-ethenocarbazole-1-spirocyclopentane-4,10,11-tricarboxylate

Abstract

The structures of two (1 IND + 2 DMAD – CH₂) adducts, and a (1 IND + 2 DMAD – CH₄O) adduct, obtained from the addition of dimethyl acetylenedicarboxylate (DMAD) to N-methylindoles (IND) having a polymethylene chain linking positions 2 and 3, have been determined by X-ray crystallography.