Transformation of 2-methyl-1-phenylethynyl-1,2,3,4-tetrahydroisoquinoline by the action of activated alkynes

Transformations of 2-methyl-1-phenylethynyl-1,2,3,4-tetrahydroisoquinoline resulting from the action of activated alkynes in trifluoroethanol and hexafluoroisopropanol were studied. In reactions with dimethyl acetylenedicarboxylate, 6-phenylethynyl-substituted benzazocines were prepared, while methyl 4-benzyl-5-(2-ethenylphenyl)-1-methyl-1H-pyrrole-3-carboxylate and benzo[d][3]-azacyclodeca[4,6,7]triene with the allene fragment, respectively, were isolated in reactions with methyl propiolate and acetylacetylene in addition to the corresponding benzazocines. As a rule, in hexafluoroisopropanol, the yields of azocines are higher. In reaction with acetylacetylene in dichloromethane, 1-(2-acetylvinyl)-1-phenylethynyltetrahydroisoquinoline is formed in high yield.