Reactions of isoquinolium ylides. Some anomalous products from acetylenes and olefins
Abstract
Isoquinolinium dialkoxycarbonyl ylides (I) and (II) and dimethyl acetylenedicarboxylate react in methanol to give the 1,10b-dihydropyrrolo[2,1-a]isoquinolines (IV) and (V); (I) and (II) in methanol alone yield the more reactive monoalkoxycarbonyl ylides (X) and dialkyl carbonate, the former dimerises to (XVII) or reacts in situ with olefins to yield 1,2,3,10b-tetrahydropyrrolo[2,1-a]isoquinolines.