Premium
Stereoisomerism in Pentaerythritol‐Bridged Cyclotriphosphazene Tri‐Spiranes: Spiro and Ansa 1,3‐Propanediyldioxy Disubstituted Derivatives
Author(s) -
Uslu Aylin,
Coles Simon J.,
Davies David B.,
Eaton Robert J.,
Hursthouse Michael B.,
Kılıç Adem,
Shaw Robert A.
Publication year - 2005
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.200400796
Subject(s) - chemistry , pentaerythritol , diastereomer , moiety , nuclear magnetic resonance spectroscopy , stereochemistry , organic chemistry , fire retardant
Four isomeric products were isolated and purified from the reaction of 1,3‐propanediol with the tri‐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 31 P 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(disubstituted) cyclophosphazene derivatives of 1 . It is also observed from the 31 P 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. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)