An unprecedented enantioselective synthesis of spiro-γ-lactams via a sequential C−H olefination/asymmetric [4+1] spirocyclization under a simple Co^II/chiral spiro phosphoric acid (SPA) binary system is reported. A range of biologically important spiro-γ-lactams are obtained with high levels of enantioselectivity (up to 98 % ee). The concise, asymmetric synthesis of an aldose reductase inhibitor was successfully achieved. Notably, contrast to previous reports that relied on the use of cyclopentadienyl or its derivatives (achiral Cp*, Cp^tBu, or chiral Cp^x) ligated Co^III complexes requiring tedious steps to prepare, cheap and commercially available cobalt(II) acetate tetrahydrate was used as an efficient precatalyst.

中文翻译：

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在简单的 CoII/手性螺磷酸二元体系下通过顺序 C-H 烯烃化/不对称 [4+1] 螺环化合成手性螺内酰胺

报道了在简单的 Co ^II /手性螺磷酸 (SPA) 二元体系下，通过连续的 C-H 烯化/不对称 [4+1] 螺环化，对螺-γ-内酰胺进行了前所未有的对映选择性合成。以高水平的对映选择性（高达 98% ee）获得了一系列生物学上重要的螺-γ-内酰胺。成功实现了醛糖还原酶抑制剂的简洁、不对称合成。值得注意的是，与之前依赖使用环戊二烯基或其衍生物（非手性 Cp*、Cp ^tBu或手性 Cp ^x）连接的 Co ^{III 的}报告相反 需要繁琐步骤来制备的复合物，廉价且可商购的四水合乙酸钴 (II) 被用作有效的预催化剂。