Abstract
Absolute stereostructure of alternaric acid (1) has been determined by the synthesis of four diastereomers of the degradation product, which had been obtained in the course of structural studies. The key synthetic steps incorporated into the total synthesis of 1 were the Julia olefination of tertiary aldehyde 6 and phenylsulfone 7 and novel one pot construction of 3-acyl-4-hydroxy-5, 6-dehydro-2-pyrone 1b via Fries-type rearrangement of the O-enol acyl group of β-keto-δ-valerolactone toward the α-position of the δ-lactone. The structure-activity relationship of analogues of 1 and synthetic intermediates has been investigated.
