Application of bis(diphenylphosphino)ethane (DPPE) in Staudinger-type N-glycopyranosyl amide synthesis

Bis(diphenylphosphino)ethane (DPPE) reacts with pyranosyl azides derived from D-glucose and D-glucuronic acid in the presence of acid chlorides to yield the corresponding glycosyl amides. Reaction rates are comparable to those with triphenylphosphine, however, the byproduct phosphine oxide is easily removed from reaction mixtures using column chromatography. The simple and clean workup allows for the formation of collections of related compounds by parallel synthesis, and the method is also applicable to scaled-up reactions. The beta-stereochemistry of the glycosyl azide precursor is retained in all cases, which is supported by X-ray crystallography in several cases.