Mitsunobu reaction of 1,5-anhydro-3,4,6-tri-O-benzyl-2-deoxy-2-hydroxymethyl-hex-1-enitols and 1,5-anhydro-2-deoxy-4,6-O-protected-hex-1-enitols. A novel method for the synthesis of 2-C-methylene glycosides and an useful alternative to Ferrier rearrangement

Abstract

A simple and convenient method for the synthesis of aryl-3,4,6-tri-O-benzyl-2-deoxy-2-methylene-hexopyranosides 5,6 and 7, glycosides which are not accessible by the conventional Ferrier rearrangement, has been described based on the Mitsunobu reaction of alcohols 3 and 4 with substituted phenols. The anomeric configurations of glycosides 5 and 6 were established by detailed NOE studies. The reaction is also successfully extended to the synthesis of phthaloyl derivative 10. A mild, neutral and non-acidic alternative to Ferrier rearrangement for the synthesis of 2,3-dideoxy-hex-2-enopyranosides has also been demonstrated with a variety of nucleophiles.