Biosynthesis of ascochitine and synthesis of its biogenetic precursors

Abstract

‘Enzymic trap’ experiments show that the main biosynthetic pathway to ascochitine (1) involves the direct reduction of the enzyme-bound ester into aldehyde (4). Therefore the complete pathway has now been assessed. Various synthetic approaches have been tried to synthesize the precursors: the use of 1,3-dithians, of an organo-lithium equivalent to the Friedel–Crafts reagent, and of phase-transfer reactions allowed for a good introduction of the label.