A rapid method for the reduction of secondary phosphine oxides under mild conditions has been developed, allowing simple isolation of the corresponding free phosphines. The methodology involves the use of pinacol borane (HBpin) to effect the reduction while circumventing the formation of a phosphine borane adduct, as is usually the case with various other commonly used borane reducing agents such as borane tetrahydrofuran complex (BH₃⋅THF) and borane dimethyl sulfide complex (BH₃⋅SMe₂). In addition, this methodology requires only a small excess of reducing agent and therefore compares favourably not just with other borane reductants that do not require a metal co‐catalyst, but also with silane and aluminium based reagents.

中文翻译：

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氧化膦可快速形成无金属的游离膦

已经开发出一种在温和条件下还原仲膦氧化物的快速方法，可以简单地分离相应的游离膦。该方法涉及使用频哪醇硼烷（HBpin）的，以实现同时避免膦硼烷加合物的形成的减少，如通常与各种其它常用的甲硼烷还原剂的情况下，如硼烷四氢呋喃复合物（BH ₃ ⋅THF）和硼烷二甲硫醚复合物（BH ₃ ⋅SMe ₂）。此外，这种方法只需要少量过量的还原剂，因此不仅可以与不需要金属助催化剂的其他硼烷还原剂进行比较，而且可以与硅烷和铝基试剂进行比较。