Biosynthesis of echinulin. The stereochemistry of aromatic isoprenylation

Abstract

The incorporation of [1,2-¹³C]acetate into echinulin has shown that the aromatic isoprenylation at the 5- and 7-positions occurs without any change in stereochemistry around the double bond of the dimethyl-allyl group and chemical degradation of echinulin, obtained by feeding [5(R)-³H]- and [5(S)-³H]mevalonate, to isopentylamine and oxidation with pea seedling diamine oxidase has shown that the isoprenylation reactions at positions 5- and 7- proceed with inversion of configuration at the allylic pyrophosphate.