Totalsynthese des Verrucarins E sowie ihre Anwendung zur Herstellung eines 13 C‐markierten Derivates desselben

Total synthesis of verrucarin E. Its application to the preparation of a 13 C‐labeled derivative. A relative high over‐all yield synthesis of verrucarin E (3‐acetyl‐4‐hydroxymethyl‐pyrrole), a secondary metabolite of the soil fungus Myrothecium verrucaria , has been achieved by condensation of ( E )‐5‐benzyloxy‐3‐penten‐2‐one with tosylmethylisocyanide and subsequent hydrogenolysis of the obtained O ‐benzyl derivative. As the closure to the pyrrole ring takes place regiospecifically, this procedure is convenient for preparing verrucarin E labeled with C‐isotopes. On the basis of the data obtained from the 13 C‐NMR. spectrum of Verrucarin E labeled with 13 C at the C(2) and C(3) positions, all the 13 C‐resonances of Verrucarin E could be assigned unambiguously.