Synthesis of Polycyclic Oxanorbornanes via a Sequential Epoxyhexopyranoside Ring Contraction−Intramolecular Diels−Alder Reaction
作者:Fritiof Pontén、Göran Magnusson
DOI:10.1021/jo970667c
日期:1997.11.1
Ring contraction of methyl 2,3-anhydro-6-deoxy-6-(furfurylthio)-alpha-D-allopyranoside with LiBr/TMU in boiling toluene gave the corresponding alpha,beta-unsaturated furanosidic aldehyde 1 together with a small amount of the corresponding oxanorbornene Diels-Alder adduct 2. Pumping a mixture of heptane and Et(3)N slowly through a SiO(2) column containing 1 and 2 shifted the ratio strongly toward 2