Efficient Synthesis of Enynecarbamates and Their Ring-Closing Metathesis/[4 + 2] Diels−Alder Cycloaddition: Synthesis of Hexahydroisoquinolines

Abstract

Enynes 5a-g were prepared in moderate to good yields from 1-(triphenylphosphoranylideneaminoalkyl)benzotriazoles. Ring-closing metathesis of 5a-f afforded functionalized dienes 6a-f, respectively, which were used in a Diels-Alder cycloaddition reaction in the synthesis of the corresponding hexahydroisoquinoline derivatives 7a-f.