Gold Catalyzed Diastereoselective Cascade Allylation/Enyne Cycloisomerization to Construct Densely Functionalized Oxygen Hetereocycles

A new tandem allylation/enyne cycloisomerization reaction was developed to construct densely functionalized oxygen hetereocycles with high diastereoselectivities from the intermolecular reaction of allylic acetates with propargylic alcohols via gold catalysis. Terminal and nonterminal propargylic alcohols take different reaction routes either to provide 3-oxa-bicyclo[4.1.0]hept-4-ene derivatives 5 or to give endocyclic rearrangement products 7 and alkoxycyclization adducts 8. Cyclopropane's stereochemistry was mainly determined by allylic substituents.