Synthetic studies towards Chlorahololides A: practical synthesis of a lindenane-type sesquiterpenoid core framework with a 5,6-double bond

Towards Chlorahololides A: a lindenane-type sesquiterpenoid framework that contains a 5,6-double bond was synthesized from simple starting materials. The reductive cyclization of a 1,6-enyne and an unusual endo-type intramolecular Heck reaction was used as key steps for ring closure.