Efficient enantiodiscrimination of chiral monophosphine oxides and boranes by phosphorus coupled 13C NMR spectroscopy in the presence of chiral ordering agents
摘要:
The synthesis of new chiral phospholanes via the corresponding oxides or boranes is reported and the analytical potential of C-13-{H-1} NMR spectroscopy in weakly ordering polypeptide liquid crystalline phases in view to differentiate between enantiomers of these chiral phosphines precursors is explored. In particular results involving organic solutions of poly-gamma-benzyl-L-glutamate (PBLG) and poly-epsilon-carbobenzyloxy-L-lysine (PCBLL) are described. This NMR approach allows determination of the enantiomeric composition, and provides therefore a new efficient alternative to classical methods usually used to analyze this class of compounds. A description of various spectral enantiodifferentiation patterns expected to be observed using C-13-{H-1} NMR of enantiomers having a spin-1/2 heteroatomic nucleus, embedded in a chiral liquid crystal is presented. (C) 2003 Elsevier Science Ltd. All rights reserved.