I. Nasibullin, A. V. Nemtarev, V. Mironov
May 17, 2014
Citations
0
Influential Citations
2
Citations
Journal
Russian Journal of Organic Chemistry
Abstract
Phosphoryl derivatives of polyphenolic compounds are increasingly used both in organic synthesis [1] and as additives to polymeric and functional materials [2–4] due to their ability to inhibit radical degradation. In the present communication we report for the first time that 1,2,3and 1,2,4-tris(trimethylsiloxy)benzenes I and II react with phosphorus trichloride to give 2-chloro-4(5)-(dichlorophosphanyloxy)-1,3,2-benzodioxaphospholes III and IV in good yields (50 and 70%, respectively). Treatment of compounds III and IV with excess chlorine at –20°C produced 93–97% of hydrolytically unstable 2,2,2-trichloro-4(5)-(tetrachloro-λ-phosphanyloxy)-1,3,2λ-benzodioxaphospholes V and VI (V , δP –23.0, –62.5 ppm; VI, δP –22.5, –63.5 ppm; CCl4). Phosphoranes V and VI reacted with sulfur dioxide to afford in nearly quantitative yield 2-chloro-4(5)-(dichlorophosphoryloxy)1,3,2λ-benzodioxaphosphole 2-oxides VII and VIII, which displayed in the P NMR spectrum signals at δP 4.8, 20.2 (VII) and 3.2, 19.5 ppm (VIII); the downfield signal belongs to the endocyclic phosphorus atom. The reaction of cyclic chlorophosphates VII and VIII with an equimolar amount of phosphorus pentachloride in methylene chloride at 20°C was chemoselective, and only the endocyclic phosphoryl group was subjected to chlorination. The phosphorus atoms in the resulting 2,2,2-trichloro-4(5)-(dichlorophosphoryloxy)-1,3,2λ-benzodioxaphospholes IX and X have different coordination numbers, which makes them promising from the viewpoint of further transformations selectively involving either phosphorane or dichlorophosphate moiety. 2-Chloro-4-(dichlorophosphanyloxy)-1,3,2-benzodioxaphosphole (III). Yield 50%, colorless liquid, bp 98°C (0.1 mm), d4 = 2.2044 g/cm, nD = 1.5990. IR spectrum (film), ν, cm: 1027 br (O–C), 466– 504 br (P–Cl). C NMR spectrum (CD3CN), δC, ppm (J, Hz): 135.10 br.m (d.d) (hereinafter, the multiplicity of the corresponding signal in the proton-decoupled spectrum is given in parentheses) (C, JPC = 7.7, JPC = 2.9), 136.36 m (d.d) (C, JPC = 11.4, JPC = 2.6), 118.0 d.d.d (d) (C, JPC = 5.5, JCH = 168.0, JCH =