Tetrahydropyran Rings from a Mukaiyama-Michael Cascade Reaction

摘要

Reactions that form complex rings are vital tools in synthetic chemistry.The significance of [4 + 2] cycloadditions,such as the Diels-Alder reaction,cannot be overstated.We have discovered a new annulation reaction that is formally a two-carbon plus four-carbon ring-forming reaction,but it proceeds through a cationic cascade.In the reaction,enones or acrylates combine with homo-allylic enol ethers,such as 1,to produce tetrahydropyrans.