A cis-directing effect towards diols by an exocyclic P-NHR moiety in cyclotriphosphazenes |
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| Authors: | Serap Beli Simon J Coles David B Davies Adem K&#x;l&#x; Elif Okutan Robert A Shaw Esra Tanr&#x;verdi Gnül Yenilmez ifti |
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| Affiliation: | aDepartment of Chemistry, Gebze Institute of Technology, Gebze, 41400 Kocaeli, Turkey;bSchool of Biological and Chemical Sciences, Birkbeck College (University of London), Malet Street, London WC1E 7HX, UK;cDepartment of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, UK |
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| Abstract: | Cyclophosphazenes containing the P-NHR moiety in an exocyclic spiro ring, N3P3Cl4NH(CH2)3O], (1), and N3P3Cl4NH(CH2)3NMe], (2), were used to investigate a possible directing effect of the P-NHR moiety on the formation of products in the nucleophilic substitution reactions with diols such as tetraethyleneglycol, 1,3-propanediol and 2,2-dimethyl-1,3-propanediol. The 31P NMR spectra of the reaction mixtures showed that only one kind of ansa product is formed in each of these reactions. X-ray crystallographic studies of the ansa products (4a), (5a), (6a) and (7a)] have provided definitive proof of the cis-directing effect of the P-NHR moiety in cyclotriphosphazenes. It is likely that hydrogen-bond interaction between the incoming nucleophile and the P-NHR moiety of the reactant accounts for the preference for products with the substituents cis to the NH group. |
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| Keywords: | Cyclophosphazene derivatives cis-Directing effect NMR X-ray crystallography |
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