Reaction of 1-benzylindole-2,3-dicarboxylic anhydride with wittig reagents

Article abstract of DOI:10.3987/COM-97-7879

Reaction of 1-benzylindole-2,3-dicarboxylic anhydride with methylene-triphenylphosphorane (Ph₃P=CH₂) and carbethoxymethylenetriphenylphosphorane (Ph₃P=CHCOOEt) gave [2-(3-carboxyindol-2-yl)-2-oxoethylidene]triphenylphosphorane derivatives, which were converted to cyclopenta[b]indol-3-ones after decarboxylation and treatment with aldehydes. On the other hand, the anhydride reacted with carbethoxyethylidenetriphenylphosphorane (Ph₃P=C(Me)COOEt) to afford a mixture of two enol lactones.