Synthesis and reactivity of a dialkyl-2H-1,2-phosphasiliren-3-olate

A heterocycle containing phosphorus, known as dialkyl-2H-1,2-phosphasiliren-3-olate 2, is synthesized through the reaction of dialkylsilylene 1 and sodium phosphaethynolate (NaOCP) in a high yield at ambient conditions. The structure of 2 is determined by single-crystal X-ray diffraction and multinuclear NMR spectroscopy. The theoretical studies are identified two nucleophilic centres located on the phosphorus (P) and oxygen (O) atoms, respectively. According to WBIs and the crystal characterization analyses, both the C−P and C−O bonds in the C−Si-P three-membered ring have significant double bond character. Reactions involving R₃SiCl and Me₂SO₄ with 2 at room temperature are also conducted at room temperature. The nucleophilic substitution reaction can also occur on oxygen atom of 2, and yield ring-retaining products 3 and 4 a–4 c, respectively. When acyl chlorides are employed as electrophiles, the derivatives of (silylmethylidyne)phosphane, 6 a–6 c, are produced as a result of the substitution of the oxygen atom.