Download full text in PDF Opens in a new window. Article suggestions will be shown in a dialog on return to ScienceDirect. ... Please enable JavaScript to use all the features on this page. ... A regiospecific, Diels-Alder based synthesis of the naphthofuranone chromophore ( ) of the rifamycins is described. ... The rubradirins, which contain a napthoquinone system reminiscent of that in , have inspired a synthetic approach conceptually related to the route depicted: ...