Radical rearrangement of 2-O-(diphenylphosphoryl)glycosyl bromides. A new synthesis for 2-deoxy disaccharides and 2-deoxy ribonucleosides
摘要:
2-Deoxy-1-O-diphenylphosphoryl glycosides react with nucleophiles under mild conditions giving access to 2-deoxy disaccharides and nucleosides. The intermediate 2-deoxy-1-O-diphenylphosphoryl compounds were generated in situ by a radical 2 --> 1 migration of the phosphate ester group. This is the first observation of a rearrangement of a phosphate ester in radicals. ESR experiments and quenching of the radical at C2 by tin hydride or tin deuteride were used to detect the intermediates and to prove their structure.