Abstract

The enantioselective synthesis of a bicyclo[4.3.0]nonene derivative bearing a quaternary carbon stereocenter is achieved by employing a desymmetrization strategy involving an intramolecular addition. The intramolecular nucleophilic addition of a highly reactive carbanion generated from an alkenyl iodide in the presence of a chiral ligand occurs with discrimination of two keto carbonyl groups to give the corresponding bicyclic compound in 81% yield and 39% ee. Asymmetric synthesis via an intramolecular desymmetrization strategy using a chiral ligand–carbanion complex represents a complementary approach to using chiral organocatalysts or chiral ligand–transition-metal complexes.

中文翻译：

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带有季碳立体中心的双环[4.3.0]壬烯衍生物的不对称合成：σ对称二酮通过分子内加成烯基阴离子的不对称化

摘要

通过采用涉及分子内加成的去对称化策略可以实现带有季碳立体中心的双环[4.3.0]壬烯衍生物的对映选择性合成。在手性配体的存在下，由烯基碘化物产生的高反应性碳负离子的分子内亲核加成发生在两个酮羰基的鉴别下，以81％的收率和39％的ee得到相应的双环化合物。通过使用手性配体-碳阴离子络合物的分子内去对称化策略进行不对称合成是使用手性有机催化剂或手性配体-过渡金属络合物的补充方法。