Ester Dienolate [2,3]-Wittig Rearrangement in Natural Product Synthesis: Diastereoselective Total Synthesis of the Triester of Viridiofungin A, A<sub>2</sub>, and A<sub>4</sub>
作者:Annett Pollex、Agnès Millet、Jana Müller、Martin Hiersemann、Lars Abraham
DOI:10.1021/jo0505270
日期:2005.7.1
3]-Wittig rearrangement was utilized to access the alkylated citric acid skeleton 6 that is characteristic for the viridiofungins and other members of the alkyl citrate family of secondary natural products. The [2,3]-sigmatropic rearrangement of (Z,Z)-15 provided the rearrangement product (±)-syn-16 in moderate yield and with very good diastereoselectivity. A Julia−Kocienski olefination efficiently served
利用酯二烯酸酯[2,3] -Wittig重排来进入烷基化的柠檬酸骨架6,该骨架是维地芬净蛋白和次要天然产物的柠檬酸烷基酯家族的其他成员的特征。(Z,Z)-15的[2,3]-σ重排提供了中等产率和非常好的非对映选择性的重排产物(±)-syn - 16。甲朱莉娅- Kocienski烯有效地提供给所述极性头(±)连接-顺式- 26用亲脂性尾部(32A - ç的viridiofungins的)。外消旋的viridiofungin前体之间的酰胺形成35a - c和对映体纯的氨基酸1-酪氨酸甲酯,然后进行制备型反相HPLC,提供了viridiofungin A((+)- 39a),A 2((+)- 39b)和A 4的异丙基二甲基酯((+)- 39c)以及非天然非对映异构体(-)- 38a - c。