The X-ray molecular structures of methyl 4,5,7,8,9,10,11,12,13,14-decahydro-7,9-dioxo-8,15-methenopyrrolo[3,2,1-op][1]benzazacyclododecine-16-carboxylate, methyl (Z)-1′,2′,4′,5′-tetrahydro-2,4′-dioxospiro(cycloheptane-1,6′-[6H]pyrrolo[3,2,1-ij]quinolin)-5′-ylideneacetate, and methyl (Z)-1,1a,2,3,4,8,9,9a-octahydro-1-methoxycarbonylmethyl-11-methoxycarbonylmethylene-12-oxo-1b,4a-epoxyethanoindolizino[2,3,4,5,6-jklm]carbazole-1-carboxylate

Abstract

The structures of three adducts obtained from substituted indoles and dimethyl acetylenedicarboxylate have been determined by X-ray crystallography. One of these reveals that its formation is via an unusual 1,3-shift of an acyl group.