Assignment of the Absolute Configuration of Polyfunctional Compounds by NMR Using Chiral Derivatizing Agents

Studies relating to the assignment of the absolute configuration of polyfunctional compounds by nuclear magnetic resonance (NMR) using chiral derivatizing agents are discussed. Recent studies have reported that the absolute configuration of an acyclic sec/sec-1,n-diol can be accurately assigned through the comparison of the NMR spectra. Sootepensin and donnaienin derivatives represent examples of polyhydroxylated substrates whose absolute configuration cannot be assigned using the model for secondary alcohols due to the anomalies observed. The configuration of the two chiral centers is determined simultaneously by analyzing the corresponding MPA amido esters without the need to carry out selective protection/deprotection protocols. Studies have also found that the presence of the MPA esterifying the primary hydroxyl is sufficiently important to modify the conformation around the O-C bond in the derivative in which the phenyls of both MPA units are close together.