General stereoselective synthesis of (E)-exo-alkylidene tetrahydrofurans via base-mediated cyclization of hydroxyl propargylic sulfones
作者:Wei-Min Dai、Mavis Yuk Ha Lee
DOI:10.1016/s0040-4020(98)00730-3
日期:1998.10
The base-promoted cyclization of a number of phenyl propargylic sulfones possessing a β-hydroxyl group afforded 5-substituted (E)-2-[(benzenesulfonyl)methylene]tetrahydrofurans 3 in >80% yield. The phenyl allenic sulfone, formed by isomerization of the phenyl propargylic sulfone under the basic conditions, is attacked by the internal alkoxide to give an allylic anion which undergoes protonation to
许多具有β-羟基的苯基炔丙基砜的碱促进的环化以> 80%的产率提供了5-取代的(E)-2-[(苯磺酰基)亚甲基]四氢呋喃3。在碱性条件下通过苯基炔丙基砜的异构化反应形成的苯基烯丙砜被内部醇盐攻击,得到烯丙基阴离子,该烯丙基阴离子经过质子化反应形成共轭的外双键。