This study reports a new series of 12 α-lithiated allylic phosphines and phosphine oxides. By incorporating Lewis base donors including diethyl ether (Et₂O), tetrahydrofuran (THF), N,N,N′,N′,-tetramethylethylenediamine (TMEDA), and N,N,N′,N′,N″,-pentamethyldiethylenetriamine (PMDETA), nine complexes were structurally characterized by single-crystal X-ray crystallography. This includes novel dilithiated allylic phosphine 4 [PhP{CHCHCH₂Li(TMEDA)}₂] and a rare hemisolvated lithiated phosphine oxide 6 [{Ph₂P(O)CHC(Me)CH₂Li}₂(TMEDA)]. Interestingly, in the solid state, P(III) complexes take advantage of Li−π interactions to the newly formed delocalized system, in comparison to P(V) complexes where the oxophillic nature of the lithium atom dominates. All 12 complexes were fully characterized in the solution state by multinuclear NMR spectroscopy. DFT calculations on isomers of monomeric lithiated complex 3 [Ph₂PCHC(Me)CH₂Li(PMDETA)] described the low energy barrier between transition steps of the subtle delocalization of the allylic chain.

中文翻译：

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锂化烯丙基膦和氧化膦的合成，结构和溶液研究

这项研究报告了一系列新的12种α-锂化的烯丙基膦和氧化膦。通过掺入路易斯碱供体，包括二乙醚（Et ₂ O），四氢呋喃（THF），N，N，N '，N '，-四甲基乙二胺（TMEDA）和N，N，N'，N '，N '' ，-五甲基二亚乙基三胺（PMDETA），九个配合物通过单晶X射线晶体学表征。这包括新型的双锂化烯丙基膦4 [PhP {CHCHCH ₂ Li（TMEDA）} ₂ ]和稀有的半溶剂化锂化氧化膦6 [{Ph ₂ P（O）CHC（Me）CH ₂ Li} ₂（TMEDA）]。有趣的是，与锂原子的亲氧性占主导的P（V）配合物相比，在固态状态下，P（III）配合物利用了Li-π相互作用与新形成的离域系统。通过多核NMR光谱对所有12种络合物在溶液状态下进行了充分表征。DFT计算的单体锂化配合物3 [Ph ₂ PCHC（Me）CH ₂ Li（PMDETA）]的异构体描述了烯丙基链微细离域的过渡步骤之间的低能垒。