Studies on the Biosynthesis of Spirostaphylotrichin A

Incorporation of 14 C‐labelled acetate and amino acids as well as of [1‐ 13 C]‐, [2‐ 13 C]‐, and [1,2‐ 13 C 2 ] acetate, L ‐[ methyl 13 C] methionine, [2,3‐ 13 C 2 ] succinate, and L ‐[2,3‐ 13 C 2 ] 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 C 4 ‐dicarboxylic acid. The latter is most likely aspartate and derived from the citric‐acid cycle. Using [2‐ 13 C, 2‐ 2 H 3 ] acetate as a precursor, the starter unit of the polyketide chain was identified.