Various synthetic approaches for [6,7,m]‐tricyclic compounds containing an oxygen‐bridged skeleton

Abstract

We report the synthesis of [6,7,5]-tricyclic compounds containing an oxabicyclo [3.2.1] octane system from 1,6-enyne carbonyl. We also synthesized [6,7,6]-tricyclic compound from 1,7-enyne carbonyl through Au-catalyzed cyclization. The synthesis of oxacyclic compounds using iodine or oxygen is environmentally friendly cyclization methods. Oxacyclic compounds are useful for synthesizing various diterpene alkaloids.