Application of a lanthanide shift-reagent for conformational and configurational assignment in the carbohydrate field

Abstract

The paramagnetic shift-reagent, tris-(2,2,6,6-tetramethylheptanedionato)europium(III), was used to resolve the n.m.r. spectrum of methyl 2,3,6-trideoxy-α-D-erythro-hexopyranoside (methyl α-amicetoside, 1); the extreme spectral dispersion thus effected permitted determination of the conformation of (1) in solution and the configuration of a 2,3-dideuterio-derivative (2), and allowed the differentiation of a pair of 4-C-ethynyl derivatives (5 and 6) obtained from (1).