(E)-2-Oxo-1-sulfonyl-3-alkenes as Reactive Hetero 1,3-Dienes. Absolutely endo-Selective Hetero Diels-Alder Reactions with Vinyl Ethers in the Presence of a Lewis Acid Catalyst

Article abstract of DOI:10.1246/cl.1994.145

(E)-2-Oxo-1-sulfonyl-3-alkenes as new hetero 1,3-dienes undergo smooth hetero Diels-Alder reactions with vinyl ethers in the presence of Eu(fod)3 or TiCl2(i-PrO)2.The reactions are absolutely endo-selective producing 2,4-cis-3,4-dihydro-2H-pyrans in excel