Domino Aza-Claisen/Mannich Cyclization Reaction from a Chiral α-Alkoxy Enamine or Sequential Alkylation of an α-Alkoxy Ester Enolate or Nitrile Anion, Followed by an Intramolecular Wittig Reaction: Two (3+2) Annulation Routes to Homochiral 4-Alkyl-4-hydroxy-2-cyclopentenone Synthesis
作者:Cyrille Kuhn、Leandros Skaltsounis、Claude Monneret、Jean-Claude Florent
DOI:10.1002/ejoc.200300045
日期:2003.7
process is based on the sequential alkylation of esters 21, 39, or nitrile 20 with acetonyl equivalents 3 or 25, followed by an intramolecular Wittig reaction. As an application, the synthesis of the naturally occurring alkylidene-cyclopentenone prostaglandin clavulone II from the spiro[cyclopentene-furan]one 5 and the formal total synthesis of (+/-)-untenone 19 has been carried out. (© Wiley-VCH Verlag
报道了对 4-烷基-4-羟基亚烷基-环戊烯酮前列腺素的对映选择性合成的研究。两个 (3+2) 环化过程允许合成同手性 4-烷基-4-羟基-2-环戊烯酮 4-5、10-11 和 17。第一个过程涉及多米诺氮杂-克莱森/曼尼希环化反应,得到来自α-烷氧基-烯胺的烷基化,衍生自手性α-烷氧基醛1、9或16,以3-碘-2-(甲氧基甲氧基)丙-1-烯(3)作为丙酮基等价物。第二个过程基于酯 21、39 或腈 20 与丙酮基等价物 3 或 25 的顺序烷基化,然后是分子内 Wittig 反应。作为应用程序,已经进行了由螺[环戊烯-呋喃]酮 5 合成天然存在的亚烷基-环戊烯酮前列腺素克拉维酮 II 和 (+/-)-untenone 19 的正式全合成。(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)