Synthesis of Rare‐Bacterial Sugar Analogs: Thomosamine and Fluorinated Thomosamine

Abstract

Bacterial carbohydrates that include unusual deoxy amino sugars represent interesting targets in drug discovery. The chemical synthesis of such probes and fluorinated analogs is a challenge that needs to be addressed. In this work, a novel approach to thomosamine (4‐amino‐4,6‐dideoxy‐d‐galactopyranose (d‐Fucp4N)) and fluorinated thomosamines from levoglucosan (1,6‐anhydro‐β‐d‐glucopyranose) is developed. The key steps involve the introduction of the C4 amino on 1,6‐anhydro bridged intermediates and the subsequent C6 reduction. Thomosamine, 3‐deoxy‐3‐fluoro‐thomosamine, and 2,3‐dideoxy‐2,3‐difluoro‐thomosamine are accessed as their protected form with a thiophenyl group at the anomeric position.