Diastereoselective construction of cis 2,6-disubstituted tetrahydropyran rings via In(OTf)3-catalyzed intramolecular 2,5-oxonium-ene cyclization: synthetic studies towards the total synthesis of zampanolide and dactylolide
作者:Teck-Peng Loh、Jian-Ying Yang、Li-Chun Feng、Yan Zhou
DOI:10.1016/s0040-4039(02)01666-0
日期:2002.9
Diastereoselective construction of 2,6-disubstituted tetrahydropyrans with an exocyclic double bond was achieved via the In(OTf)3-catalyzed intramolecular 2,5-oxonium-ene cyclization. Its application was further demonstrated by the synthesis of a common intermediate for both zampanolide and dactylolide, fragment I, with a total yield of 42% in three steps starting from (2E)-3-bromobut-2-enal.
通过In(OTf)3催化的分子内2,5-氧-烯环化反应,可以实现具有环外双键的2,6-二取代的四氢吡喃的非对映选择性。从(2 E)-3-溴丁-2-烯醛开始的三个步骤中,合成了用于苯甲环戊内酯和环己内酯的通用中间体片段I,进一步证明了其应用。该中间体的总收率为42%。