Pyridinylidenaminophosphines: Facile Access to Highly Electron‐Rich Phosphines
Pyridinylidenaminophosphines: Facile Access to Highly Electron‐Rich Phosphines
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DOI：
10.1002/chem.201904621
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发表时间：
2019-12
期刊：
影响因子：
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通讯作者：
Philipp Rotering;Lukas F. B. Wilm;Janina A. Werra;Fabian Dielmann
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文献类型：
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作者：
Philipp Rotering;Lukas F. B. Wilm;Janina A. Werra;Fabian Dielmann
摘要富电子叔膦是化学合成中有价值的物种。然而，它们作为配体在催化和化学计量反应中作为试剂的广泛应用往往受到合成成本的限制。在这里，我们报道了一系列具有1-烷基吡啶-4-亚乙基氨基和1-烷基吡啶-2-亚亚氨基取代基的膦的合成和性质，这些取代基可以从商业上可获得的氨基吡啶和氯膦以非常短的和可扩展的路线获得。Tolman电子参数(TEP)值的测定表明，电子给体能力可以由氨基吡啶主链上的取代基模式来调节，它可以超过普通的烷基膦和N-杂环卡宾。通过与CO2和CS2形成Lewis碱加合物，证明了新的膦作为强亲核试剂在膦介导的转化中的潜力。此外，还探讨了新的膦对CuI、AuI和PdII金属中心的配位化学，并描述了从空气稳定的膦盐开始将最碱性的膦引入金属络合物的简便方法。
Abstract Electron‐rich tertiary phosphines are valuable species in chemical synthesis. However, their broad application as ligands in catalysis and reagents in stoichiometric reactions is often limited by their costly synthesis. Herein, we report the synthesis and properties of a series of phosphines with 1‐alkylpyridin‐4‐ylidenamino and 1‐alkylpyridin‐2‐ylidenamino substituents that are accessible in a very short and scalable route starting from commercially available aminopyridines and chlorophosphines. The determination of the Tolman electronic parameter (TEP) value reveals that the electron donor ability can be tuned by the substituent pattern at the aminopyridine backbone and it can exceed that of common alkylphosphines and N‐heterocyclic carbenes. The potential of the new phosphines as strong nucleophiles in phosphine‐mediated transformations is demonstrated by the formation of Lewis base adducts with CO2 and CS2. In addition, the coordination chemistry of the new phosphines towards CuI, AuI, and PdII metal centers has been explored, and a convenient procedure to introduce the most basic phosphine into metal complexes starting from air‐stable phosphonium salt is described.