Practical synthetic protocols of enantiopure 1,1′-binaphthyl-2,2′-dicarboxylic acid and 2,2′-dicyano-1,1′-binaphthyl starting from optically active dibromide precursor

Dilithiation of optically active 2,2′-dibromo-1,1′-binaphthyl 2 with t-BuLi followed by carboxylation of the resulting dilithio-intermediate 3 with CO2 gave optically active 1,1′-binaphthyl-2,2′-dicarboxylic acid 1, which was further transformed to its dicyano derivative 4. Both of these transformations were carried out in a one-pot operation and the products were obtained in excellent yields with no observable racemization.