The metal-free reduction of a range of phosphine(V) oxides employing oxalyl chloride as an activating agent and hexachlorodisilane as reducing reagent has been achieved under mild reaction conditions. The method was successfully applied to the reduction of industrial waste byproduct triphenylphosphine(V) oxide, closing the phosphorus cycle to cleanly regenerate triphenylphosphine(III). Mechanistic studies and quantum chemical calculations support the attack of the dissociated chloride anion of intermediated phosphonium salt at the silicon of the disilane as the rate-limiting step for deprotection. The exquisite purity of the resultant phosphine(III) ligands after the simple removal of volatiles under reduced pressure circumvents laborious purification prior to metalation and has permitted the facile formation of important transition metal catalysts.

中文翻译：

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轻度一锅还原膦（III）及其金属催化剂上的膦（V）氧化物

在温和的反应条件下，已经实现了使用草酰氯作为活化剂和六氯乙硅烷作为还原剂的一系列膦（V）氧化物的无金属还原。该方法成功地用于减少工业废物副产物三苯基膦（V）的氧化，关闭磷循环以干净地再生三苯基膦（III）。机理研究和量子化学计算支持中间体phospho盐的离解氯离子对乙硅烷硅的攻击，这是脱保护的限速步骤。