Reaction of 3, 3-dimethyl-and 3-spirocyclohexyl-tetrahydroisoquinolines with alkynes

It has been found that 2, 3, 3-trimethyl-1-phenyl- and 1, 2-dimethyl-3-spirocyclohexyltetrahydro-isoquinolines react with activated alkynes in methanol with cleavage of the tetrahydropyridine ring to give methoxybenzyl- and methoxyethylbenzenes, and in boiling acetonitrile form N-butenoyl derivatives from N-methylspirocylohexyltetrahydroisoquinoline by its reaction with acetylacetylene. © 2012 Springer Science+Business Media, Inc.