The bengazoles are marine natural products with unique structure, containing two oxazole rings flanking a single carbon. They show very potent antifungal activity. The total syntheses of bengazole C and E are described following a convergent route which involves diastereoselective cycloaddition of an appropriately substituted nitrile oxide with a butane-1,2-diacetal-protected alkenediol as the key step.
The metabolites produced in liquid culture by the fungus Lachnellulafuscosanguinea (Rehm) Dennis have been examined and two antifungal agents, lachnelluloic acid and lachnellulone, have been isolated. The structure of lachnelluloic acid has been established as (−)-4-hydroxy-3-octanoyl-6-pentyl-5,6-dihydro-2-pyrone (1) by chemical and spectroscopic methods. The total synthesis of racemic lachnelluloic acid, starting from 6,8-tridecanedione (6) is reported. Lachnelluloic acid (1) shows strong antifungal activity against Ceratocystisulmi, the causative agent of Dutch elm disease.
Cover Picture: Total Synthesis of Leupyrrins A1
and B1
, Highly Potent Antifungal Agents from the Myxobacterium Sorangium cellulosum
(Chem. Eur. J. 14/2017)
