Facile synthesis of enantiopure tricyclic furanyl derivatives via tungsten-mediated cycloalkenation reactions and Diels–Alder reactions

Chiral furanyl diene 1 is easily prepared from cycloalkenation of chiral tungsten alkynol with acetaldehyde, followed by demetalation with Me3NO. This diene bears a chiral 1,3-dioxolane group to control diastereoselective Diels–Alder reactions with electron-deficient olefins. The chiral 1,3-dioxolane substituent of the cycloadducts was degraded to a hydrogen atom to make these molecules possess a common furanyl functionality.