Stereoisomerism in pentaerythritol-bridged cyclotriphosphazene tri-spiranes: spiro and ansa 1,3-propanediyldioxy disubstituted derivatives

Article English OPEN
Aylin, U. ; Coles, Simon J. ; Davies, David B. ; Eaton, R.J. ; Hursthouse, Michael B. ; Kiliç, A. ; Shaw, Robert A. (2005)

Four isomeric products were isolated and purified from the reaction of 1,3-propanediol with the tetra-spirane cyclophosphazene-organophosphate compound (1): viz. the di-monospiro (2a), di-monoansa (2b) and two monospiro-monoansa derivatives (2c) and (2d). It is shown by 31P NMR spectroscopy on addition of a chiral solvating agent (CSA) that both the di-monospiro (2a) and di-monoansa (2b) derivatives are racemates, as expected, whereas no splitting of NMR signals occurred on addition of CSA to solutions of (2c) and (2d). It is found by X-ray crystallography that the two monospiro-monoansa spirane derivatives, (2c) and (2d), are meso diastereoisomers, which represent a new case of the stereochemistry of bis di-substituted cyclophosphazene derivatives of (1). It is also observed from the 31P NMR spectrum of the reaction mixture, supported by the yields of pure compounds, that formation of a spiro group is about 4.5 times more likely than that of an ansa moiety under the conditions of the reaction.
  • References (7)

    [1] [1a] R. A. Shaw, Pure and Applied Chem., 1980, 52, 1063. [1b] J-F. Labarre, Topics Curr. Chem. 1985, 129,173-230. [1c] V. Chandrasekhar, V. Krishnan, in Advances in Inorganic Chemistry Including Bioinorganic Studies, 2002, 53, Ed. A.G. Sykes. Academic Press, Amsterdam.

    [2] A. H. Alkubaisi, H.G. Parkes, R. A. Shaw, Heterocycles, 1989, 28, 347-358.

    [3] [3a] H. A. Al-Madfa, L. S. Shaw (neé Gözen), R. A. Shaw, Phosphorus, Sulfur, Silicon 1991, 56, 133; [b] H. A. Al-Madfa, Ph.D. Thesis, 1988, University of London.

    [4] S. J. Coles, D. B. Davies, R. J. Eaton, M. B. Hursthouse, A. Kılıç, R.A. Shaw, A. Uslu, Eur. J. Org. Chem., 2004, 1881-188.

    [5] [5a] S. R. Contractor, M. B. Hursthouse, H.G. Parkes, L. S. Shaw (neé Gözen), R.A. Shaw, H. Yılmaz, Chem. Commun., 1984, 675. [5b] H.R. Allcock, K.D. Lavin, G.H. Riding, P.R. Susko, R.R. Whittle, J. Amer. Chem. Soc, 1984, 106, 2337. [5c] S. R. Contractor, M. B. Hursthouse, H. G. Parkes, L.S. Shaw (née Gözen), R. A. Shaw, H. Yılmaz. Phosphorus Sulfur, 1986, 28, 267-275.

    [6] S. Beşli, S. J. Coles, D. B. Davies, R. J. Eaton, M. B. Hursthouse, A. Kılıç, R. A. Shaw, G. Yenilmez Çiftçi, S. Yeşilot. J. Amer. Chem. Soc., 2003, 125, 4943-4950.

    [7] The starting material, compound (1), is a linear tetra-spirane, in which all the organophosphate and cyclotriphosphazene spirane moieties are six-membered and the shape of the ring system may be described as planar/chair/chair/planar. The introduction m la n r

  • Metrics
    No metrics available
Share - Bookmark