there is provided a novel method of synthesizing certain tetracyclic quinones . in particular , there is provided a novel route to the synthesis of - 7 - deoxydaunomycinone and analogs thereof which includes the provision of novel tetrahydronaphthoquinones and tetracyclic quinone intermediates . the compounds of the present invention are provided through a route comprising a diels - alder addition of certain isobenzofurans to certain novel tetrahydronaphthoquinones . the products of the synthetic route provided herein may be converted into compounds of known antibiotic and antineoplastic activity .