Reductive activation of arenes. VII. Alkylation of 9-cyanoanthracene two-electron reduction products in liquid ammonia.

The reactions of the 9-cyanoanthracene dianion generated by the action of two equivalents of potassium in liquid ammonia with primary alkyl iodides and bromides gave 9-cyano-9,10-dialkyl-9,10-dihydroanthracenes. The alkylation of the 9-cyano-9,10-dihydro-9-anthryl anion generated by the two-electron reduction of 9-cyanoanthracene in liquid ammonia in the presence of ammonium chloride gave 9-cyano-9-alkyl-9,10-dihydroanthracene. The results obtained by using cyclopropylmethyl bromide as model reagent suggest these reactions to proceed through S_N mechanism. The spatial structure of 9,10-dihydroanthracene derivatives obtained is discussed.