Reductive alkylation of anthracene, 9, 10-dimethylanthracene, 1, 4-dimethylanthracene, benz (a) anthracene and dibenz (a, h) anthracene via treatment of the dilithio adducts in liquid ammonia with alkyl halides proceeds stereo selectively to furnish high yields of the corresponding cis-dialkyldihydro derviatives.