Studies on the Biosynthesis of Spirostaphylotrichin A

Incorporation of 14C‐labelled acetate and amino acids as well as of [1‐13C]‐, [2‐13C]‐, and [1,2‐13C2] acetate, L‐[methyl13C] methionine, [2,3‐13C2] succinate, and L‐[2,3‐13C2] aspartate into spirostaphylotrichin A (1) by Staphylotrichum coccosporum demonstrates that the building blocks of 1 are 5 units of acetate/malonate, 1 unit of methionine, and a C4‐dicarboxylic acid. The latter is most likely aspartate and derived from the citric‐acid cycle. Using [2‐13C, 2‐2H3] acetate as a precursor, the starter unit of the polyketide chain was identified.