The total synthesis of structural analogues of the unnatural, C-6-hydroxylated isokalafungins and isonanaomycins is described. The new compounds show improved antibiotic activity and support theories for a mechanism of action which base on the formation of reactive quinone methides. Calculations of the molecular structures show that the chromophore of the most active 9-methyl derivatives 28 and 32 is bended off along its 5-CO-10-CO axis. ...
