Introduction

Phospholanes are very promising building blocks for designing ligand systems and transition metal complexes, especially for enantioselective catalysis purposes.¹ The five-membered phosphorus-containing heterocycles have been extensively studied since the development of the first chiral phospholane ligands by Burk et al. in the early 1990s. The BPE (1,2-bis(phospholano)ethane) and DuPHOS (1,2-bis(phospholano)benzene) ligand families showed remarkable stereoselectivity in rhodium catalyzed hydrogenation reactions.² In the following years, many related phospholane ligands were synthesized and applied to enantioselective catalysis processes, giving insight into electronic and steric dependencies of structural motives on the performance.¹

Also for other reaction types phospholane based ligands in complexes successfully act as catalysts, for example in cycloadditions,³ copolymerizations⁴ or acylation reactions.⁵ The latter where amongst others investigated by Vedejs et al. who developed a bicyclic chiral phospholane catalyst with high performance in enantioselective acylation reactions. Bicyclic phospholanes as possible ligands were also developed by Koenig et al. via cyclozirconation reactions leading to fused five-membered heterocycles with two equal (P,P) or different (P,Si or P,Ge) functionalities at opposite positions.⁶ Similar bicyclic systems with one amine and one phosphinic acid functionality are investigated as artificial TPMPA analogs.⁷

More recently the coordination behavior of phospholane bearing ligands to a higher variety of transition metals like Mn(I),⁸ Mo(III),⁹ Ni(II),¹⁰ Cu(I),¹¹ Ag(I)¹² and Au(I)^{12, 13} was investigated.

However, all so far published routes towards phospholane derivatives start from building up the phospholane ring step by step from precursor molecules.^{1, 14} Interestingly, synthetic approaches to phospholanes employing addition reactions or formal hydrogenation of the unsaturated phosphole analogs have not been reported to best of our knowledge. For the latter multiple synthetic pathways are well-established and phospholes are a thriving subject of investigation mainly owing to their luminescence properties.¹⁵

Herein we describe a synthetic approach towards phospholanes via twofold C−H-addition of DMSO to a phosphole ring, during which multiple stereogenic centers are implemented in the resulting fused phospholane oxothiolane bicycle in a stereoselective fashion.

中文翻译：

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磷杂环戊烷通过两次 C-H 加成到磷环上

 介绍

磷杂环己烷是用于设计配体系统和过渡金属配合物的非常有前途的构建模块，特别是对于对映选择性催化目的。 ¹ 自从Burk等人开发出第一个手性磷杂环戊烷配体以来，五元含磷杂环得到了广泛的研究。 20世纪90年代初。 BPE（1,2-双（磷杂环）乙烷）和 DuPHOS（1,2-双（磷杂环）苯）配体家族在铑催化氢化反应中表现出显着的立体选择性。 ² 在接下来的几年里，许多相关的磷杂环戊烷配体被合成并应用于对映选择性催化过程，深入了解结构动机对性能的电子和空间依赖性。 ¹

对于其他反应类型，配合物中的基于磷杂环戊烷的配体也成功地充当催化剂，例如在环加成、 ³ 共聚 ⁴ 或酰化反应中。 ⁵ Vedejs 等人对后者进行了研究。他开发了一种在对映选择性酰化反应中具有高性能的双环手性磷杂环戊烷催化剂。 Koenig 等人还开发了双环磷杂环戊烷作为可能的配体。通过环锆化反应产生稠合五元杂环，在相反位置具有两个相同的（P，P）或不同的（P，Si或P，Ge）官能团。 ⁶ 研究了具有一种胺和一种次膦酸官能团的类似双环系统作为人工 TPMPA 类似物。 ⁷

最近，磷杂环戊烷配体与更多种类的过渡金属如 Mn(I)、 ⁸ Mo(III)、 ⁹ Ni(II)、 ¹⁰ Ag(I) ¹² 和Au(I) ^{12, 13} 进行了研究。

然而，迄今为止所有已发表的磷杂环戊烷衍生物路线都是从前体分子逐步构建磷杂环戊烷环开始的。 ^{1, 14} 有趣的是，据我们所知，利用不饱和磷杂环己烷类似物的加成反应或形式氢化来合成磷杂环戊烷的方法尚未见报道。对于后者，多种合成途径已经成熟，并且磷化物主要由于其发光特性而成为热门的研究对象。 ¹⁵

在此，我们描述了一种通过将 DMSO 双重 C-H 加成到磷杂环戊烷环上来合成磷杂环戊烷的方法，在此过程中，以立体选择性方式在所得的融合磷杂环戊烷氧硫杂环戊烷自行车中实现了多个立体中心。