1, -Binaphthyl, 2,2 -dilithio

Different amino-, alkyl-, and aryl-substituted phosphepines 7-12 and 90 were also obtained in two steps directly from binaphthyl 84 and dichloro-Ar,Ar-dialkylphosphinamines, dichloro(alkyl)phosphines, or dichloro(aryl)phosphines in 60-80% yields. This method requires initial metallation of 2,2 -dimethylbinaphthyl 84 with -BuLi and isolation of dilithio salt in the crystalline form <2004TA2621, 2003JOM(675)91, 2002TL4977>. 

Novel -symmetric chiral arsepin 61 possessing the 1,1 -binaphthyl-2,2 -bis(methylene) backbone was prepared using (S)-(—)-l,l -bi-2-naphthol 84 as the chiral substrate. The dilithio derivative 86, generated from (S)-2,2 dimethyl-1,1 -binaphthyl 85 and Avy-biitvllithiuru, reacted with PhAsBr2 to give arsepin 61 (Scheme 7) <2002TA2187>. 

It appears remarkable that benzylic and poly(p-phenylene diselenide polymers are able to incorporate additional selenium atoms in to the chain through a simple melt alloying process, thus giving products whose structures are intermediate between organic and inorganic polymers [224,227]. Recently, poly(l,l -binaphthyl-2,2 -diselenide) was prepared along with other compounds when 2,2 -dilithio-l,l binaphthyl was reacted with selenium followed by aerial oxidation [228]. 

Many attempts were made to access optically active tetraphenylenes in past years owing to their unique structures and properties. In 2000, Rajca et al. [44] reported that a CuBr2-mediated oxidation coupling of partially resolved (/ )-2,2 -dibromo-l,l -binaphthyl 89 afforded R)-90 in 20% yield with 95% ee (Scheme 5.18). This method was based on the configurational stability of 2,2 -dilithio-l,l -binaphthyl. Amplification of the enantiomeric excess was also observed. Interestingly, when ( )-89 was used under the same condition, ( )-90 was isolated in only a trace amount. 

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