Tandem enlargement of the tetrahydropyridine ring in 1-aryl-tetrahydroisoquinolines using activated alkynes-a new and effective synthesis of benzoazocines

Tetrahydroisoquinolines 3a-e underwent piperidine ring enlargement under the action of activated alkynes, giving benzoazocines 4, 5 and 7-11 in high yields. © 2006 Elsevier Ltd. All rights reserved.