Regioselective Synthesis of Substituted Rubrenes

Article abstract of DOI:10.1021/jo00300a043

The development of two complementary synthetic routes to 5,6,11,12-tetraphenylnaphthacene (rubrene) derivatives is described.In one approach, selective nucleophilic addition of aryllithiums to diarylnaphthacenequinones (13, 14, 16), followed by HI aromatization of the corresponding diols, allows for the convenient preparation of a wide variety of selectively functionalized rubrenes.Symmetrically and unsymmetrically di- and tetrasubstituted rubrenes have been prepared, as well as several "end-capped" versions.In a second route, cycloaddition of 1,3-diphenylisobenzofuran with the naphthyne 7 (Ar= Ph) followed by Lewis acid mediated deoxygenation of the resultant oxo-bridged adduct gives rubrene in a particularly convergent manner.Elaboration through the use of substituted isobenzofurans (i.e. 9-11) allows for the analogous preparation of substituted rubrenes (45-47).