| Abstract: | Reaction of isoquinolinium bis(ethoxycarbonyl)methylide (I) with diketene gave diethyl 1-acetyl-2,3-dihydro-2-oxopyrrolo2,1-α]isoquinoline-3,3-dicarboxylate (VI), which on hydrolysis with dilute hydrochloric acid afforded ethyl 1-acetyl-2-hydroxypyrrolo2,1-α]isoquinoline-3-carboxylate (IX) and ethyl 3-methylpyrrolo2,1-α]isoquinoline-3-carboxylate (X). On the other hand, isoquinolinium cyanoethoxycarbonylmethylide (IIa) reacted with diketene to give isoquinolinium cyano(3-ethoxycarbonyloxy-3-butenoyl)methylide (XIIIa) which was isomerized to isoquinolinium cyano(3-ethoxycarbonyloxy-2-butenoyl)methylide (XIII). Similarly, reactions of isoquinolinium cyanomethoxycarbonylmethylide (IIb) and pyridinium cyanoalkoxycarbonyl-methylide (IIIa,b) with diketene gave rise to the corresponding cyano(3-alkoxycarbonyloxy-3-butenoyl)methylides (XIIb, XVIa,b). |
