NMR separation of beta-prochiral protons to the ether oxygen of chiral esters with lanthanide shift reagents.
The use of chiral ester derivatives of 2-phenylethan-1-ol in conjunction with chiral lanthanide shift reagents allows separation of the prochiral and homo prochiral protons to the ether oxygen in the NMR spectrum. Specifically the alpha- and beta- protons of the N-(4-nitrophenylsulfonyl)-L-phenylalanyl ester of 2-phenylethan-1-ol, after addition of either europium d- or l-3-heptafluorobutyrylcamphorate or ytterbium d-3-heptafluorobutyrylcamphorate are differentiated. This is the first report of the NMR separation of prochiral protons beta to an ester linkage. [reaction: see text]
Coxon
J M
JM
Department of Chemistry, University of Canterbury, Christchurch, New Zealand. j.coxon@chem.canterbury.ac.nz
Cambridge
J R
JR
Nam
S G
SG