THE SYNTHESIS OF NOVEL HIGHLY SUBSTITUTED BENZENE-DERIVATIVES FOR USEIN PALLADIUM-CATALYZED CROSS-COUPLING REACTIONS

A combination of conventional electrophilic aromatic substitution reac tions and low-temperature ortho-directed lithiations has been used in the efficient synthesis of some novel highly substituted benzene deriv atives containing alkoxy, alkyl, bromo, cyano, fluoro and iodo functio ns. The use of such compounds is exemplified by selective palladium-ca talysed cross-coupling reactions to generate a series of liquid crysta lline terphenyls with a lateral fluoro substituent ortho to a lateral cyano group.