Stereospecific Synthesis of (-)-allo-Muscarine from D-Glucose: Novel Routes to the Key Chiral Synthon

Abstract

The key chiral synthon in a novel synthesis of (-)-allo-muscarine from D-glucose has been prepared by three independent routes. The most efficient one includes a four-step conversion via the 4-O-benzoyl derivatives of starting 2,5-anhydro-3,5-di-O-methanesulfonyl-L-idose ethylene acetal (2a) into 2,5-anhydro-3,6-dideoxy-L-lyxo-hexose ethylene acetal (4b). The intermediate 4b was efficiently converted into the chiral synthon 2,5-anhydro-4-O-benzoyl-3,6-dideoxy-L-arabino-hexose (4c) by Mitsunobu reaction.