Treatment of cis-fused bicyclic diene dicarboxylates with Li/naphthalene triggers a tandem ring-opening and transannular cyclization process that stereoselectively yields hydroazulenes and hydrindanes derivatives. Cyclononadienyl diesters, which can be isolated after the ring-opening step by judicious choice of the reaction conditions, undergo a tandem conjugate addition/intramolecular Michael addition upon treatment with chiral lithium amides to give bicyclic β-amino esters in a process where 4 contiguous stereocenters are formed with high diastereocontrol. A concise route toward the highly enantioenriched AEF ring core of the aconitine-type alkaloids has been developed as an application of this methodology. The starting cis-fused bicyclic dicarboxylates are easily prepared in one step by reductive alkylation of diisopropyl phthalate (Na/THF, followed by the appropriate bis-electrophiles).

中文翻译：

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九元和十元碳环跨环化立体选择性合成氢化茚和氢化芴衍生物

用锂/萘处理顺式稠合双环二烯二羧酸酯引发串联开环和跨环环化过程，立体选择性地产生氢化茚和氢化茚衍生物。环壬二烯基二酯可在开环步骤后通过明智地选择反应条件进行分离，在用手性氨基化锂处理后进行串联共轭加成/分子内迈克尔加成，在 4 个连续立体中心的过程中得到双环 β-氨基酯形成高非对映控制。作为这种方法的应用，已经开发了一种通往乌头碱型生物碱的高度对映体富集的 AEF 环核心的简明路线。起始顺式-融合的双环二羧酸容易在一个步骤中由二异丙基邻苯二甲酸酯的还原性烷基化制备（钠/ THF，随后适当的双-electrophiles）。