Intramolecular Diels–Alder reaction of functionalized trienes: synthesis of medium-ring lactones †
作者:Annamaria Deagostino、Jacques Maddaluno、Mariella Mella、Cristina Prandi、Paolo Venturello
DOI:10.1039/a707913c
日期:——
(E)-pent-2-enal. The reaction is initiated by a regioselective metallation at the γ site of the unsaturated system that immediately induces 1,4-eliminative ring fission, and stereoselectively affords hydroxy-functionalized E-1,3-dienes. The esterification of those hydroxy dienes with acryloyl chloride gives activated trienes, suitable for intramolecular Diels–Alder reaction that yields medium-ring lactones. This
对于三烯体系,已经开发了一种简单的制备方法,从巴豆醛和(E)-戊-2-烯醛衍生的环状α,β-不饱和缩醛开始。该反应由不饱和系统的γ位上的区域选择性金属化反应引发,该反应立即引起1,4-消除的环裂变,并立体选择性地提供羟基官能化的E-1,3-二烯。那些羟基二烯与丙烯酰氯的酯化反应生成活化的三烯,适用于分子内Diels-Alder反应,产生中等环内酯。就二烯和亲二烯体之间的系链的长度和取代而言,该方法相对通用。系链中其他立体异构中心的存在在环加成步骤中引起了令人感兴趣的选择性,这些选择性已得到报道和讨论。