Regioselective inversion of the hydroxyl group in d-ribo-phytosphingosine via a cyclic sulfate and bis-sulfonate intermediate

摘要

The selective synthesis of d-xylo-and d-lyxo-phytosphingosines from commercially available d-ribo-phytosphingosine is described. Thermolysis of the N-carbonyl protected cyclic sulfate led to an inversion of configuration of the proximal hydroxyl group to give the xylo-isomer, whereas the corresponding bis-sulfonate resulted in an inversion of configuration of the distal hydroxyl group to give the lyxo-isomer. This study allowed the comparison between a cyclic sulfate and a bis-sulfonate in an intramolecular substitution reaction involving a carbonyl oxygen nucleophile.