Synthesis of 5-(2-methoxy-1-naphthyl)- and 5-[2-(methoxymethyl)-1-naphthyl]-11H-benzo[b]fluorene as 2,2'-disubstituted 1,1'-binaphthyls via benzannulated enyne–allenes

5-(2-Methoxy-1-naphthyl)- and 5-[2-(methoxymethyl)-1-naphthyl]-11H-benzo[b]fluorene were synthesized by treatment of the corresponding benzannulated enediynes with potassium tert-butoxide in refluxing toluene to give benzannulated enyne–allenes for the subsequent Schmittel cascade cyclization reactions. The structures of these two 5-(1-naphthyl)-11H-benzo[b]fluorenes could be regarded as 2,2'-disubstituted 1,1'-binaphthyls with the newly constructed benzofluorenyl group serving as a naphthyl moiety.