Synthesis and Biological Evaluation of Sugars Containing α,β‐Unsaturated γ‐Lactones

Abstract

The stereocontrolled synthesis of new sugar derivatives carrying the α,β‐unsaturated δ‐lactone (butenolide) moiety is described. Sugar‐fused or sugar‐linked butenolides can be constructed by an efficient reaction sequence involving Wittig olefination of 3‐ or 5‐keto sugars and intramolecular cyclization of the intermediate γ‐hydroxy α,β‐unsaturated esters. The antimicrobial activities of the products and that of a known sugar‐derived pyranoid α,β‐unsaturated δ‐lactone were investigated against six pathogenic bacteria and six fungi. The pyranoid α,β‐unsaturated δ‐lactone 29 proved to be the most active compound in this series towards the plant pathogenic fungi Colletotrichum coffeanum (coffee berry disease) and Pyricularia oryzae (rice blast disease).(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)