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Chiral separation and CD characterisation of enantiomeric cyclotriphosphazene derivatives
Author(s) -
Bui Tam T.T.,
Coles Simon J.,
Davies David B.,
Drake Alex F.,
Eaton Robert J.,
Hursthouse Michael B.,
Kılıç Adem,
Shaw Robert A.,
Yeşilot Serkan
Publication year - 2005
Publication title -
chirality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.43
H-Index - 77
eISSN - 1520-636X
pISSN - 0899-0042
DOI - 10.1002/chir.20187
Subject(s) - chemistry , stereocenter , enantiomer , diastereomer , circular dichroism , chiral derivatizing agent , chiral column chromatography , piperazine , proton nmr , nuclear magnetic resonance spectroscopy , chiral resolution , chiral auxiliary , stereochemistry , enantioselective synthesis , organic chemistry , catalysis
Abstract The gem‐disubstituted cyclotriphosphazene 1 reacted with piperazine (pip) to give the piperazine‐bridged derivative 2 , which is expected to exist in meso and racemic forms because the two PCl (pip) groups are stereogenic. The proton‐decoupled 31 P NMR spectrum of 2 gave rise to two similar sets of ABX signals in a 1:1 ratio, consistent with formation of diastereoisomers. The meso and racemic forms of compound 2 were separated by column chromatography on silica gel and characterised by elemental analysis, mass spectrometry, 31 P NMR spectroscopy, and X‐ray crystallography. Using HPLC with a chiral stationary phase, the racemic form of compound 2 was further separated into enantiomers, which were characterised by circular dichroism (CD) spectroscopy. This is the first report of the separation of enantiomers in the field of cyclophosphazene chemistry and hence the first CD spectra of derivatives in which the cyclophosphazene ring is at the chiral centre. © 2005 Wiley‐Liss, Inc. Chirality 17:438–443, 2005.