Abstract
The 1, 3-dipolar cycloaddition of dicyanoacetylene (IIb) to isoquinolinium ylides did not give the primary adduct but the aromatized and/or isomerized products. Further, in the reaction of isoquinolinium bis(methoxycarbonyl)methylide (Ia), possibly a rearranged addition product, 1, 10b-dihydropyrrolo[2, 1-α]isoquinoline (VII), was obtained beside 2, 3-dihydropyrrolo[2, 1-α]isoquinoline (Va) and pyrrolo[2, 1-α]isoquinoline (VIa). In the reaction of isoquinolinium cyano(methoxycarbonyl)methylide (Ib), 2, 3-dihydropyrrolo[2, 1-α]isoquinoline (VIII), formed by the liberation of a methoxycarbonyl group, was obtained in addition to VIa and pyrrolo[2, 1-α]isoquinoline-1, 2, 3-tricarbonitrile (VIb).
