REGIOSELECTIVE SYNTHESIS OF SUBSTITUTED RUBRENES

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 diaryl-naphthacenequinones (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). © 1990, American Chemical Society. All rights reserved.