A convenient approach for building the spiro[4.4]nonane system present in fredericamycin A, an antitumour anti biotic, is described and the X-ray crystal structure presented. ... Fredericamycin A (1),1 an antitumour antibiotic produced by Streptomyces griseus, possesses an entirely novel spiro[4.4]no- nane system which has not been observed in any other types of antibiotics. It has certain interesting spacial characteristics (the two aromatic portions are nearly at right ...