Total synthesis of (+)-intricarene using a biogenetically patterned pathway from (−)-bipinnatin J, involving a novel transannular [5+2] (1,3-dipolar) cycloaddition
作者:Bencan Tang、Christopher D. Bray、Gerald Pattenden
DOI:10.1039/b910572g
日期:——
it gave (+)-intricarene 1, which is found in P. kallos, via a novel transannular [5+2] (or 1,3-dipolar) cycloaddition involving the butenolide-oxidopyrylium ion intermediate 31. We believe that this total synthesis of (+)-intricarene 1 mimics its most likely origin in nature viaoxidation of (−)-bipinnatin J (4a), presumably involving photochemically generated singlet oxygen or possibly a P450 monooxygenase
描述了一种不对称合成的呋喃丁烯内酯基的大环二萜(-)-联吡啶类化合物J(4a),该化合物是从八方正八叶假单胞菌高联杆菌中分离出来的。合成的基础是从(+)-缩水甘油精制手性内酯取代的乙烯基碘化物26b,然后与苯乙烯基糠醛27进行分子间斯蒂勒偶联反应,生成28a,然后进行分子内Nozaki–Hiyama–Kishi烯丙基化反应,28b → 4a。VO(acac)2 – t BuO 2处理(-)-联吡啶J(4a)小时,随后互变异构hydroxypyranone产物的乙酰化7 / 8,下一个得到acetoxypyrone 30。将乙酰氧基吡喃酮30加热至乙腈在DBU存在下,得到(+)-intricarene 1,其存在于P中。kallos,通过一种新颖的跨环式[5 + 2](或1,3-偶极)环加成反应,涉及丁烯内酯-氧化吡啶鎓离子中间体31。我们相信,(+)-tric香烯1的这种全合成模拟了其最可