e.g. Filippa Pettersson or Cancer Res. 75(6) , 1102-12, (2015) or 10.1002/anie.201600521
Practical synthesis of 1, 1'-binaphthyl-2-carboxylic acids via side chain oxidation of 2-methyl-1, 1'-binaphthyls.
…, S Okada, T Suzuki, S Handa, H Hashimoto
Index: Miyano, Sotaro; Okada, Shin-ichi; Suzuki, Toshiyuki; Handa, Shigeru; Hashimoto, Harukichi Bulletin of the Chemical Society of Japan, 1986 , vol. 59, p. 2044 - 2046
Four 1, 1′-binaphthyl-2-carboxylic acids were obtained in 38–53% isolated yield via three- stage oxidation of 2-methyl-1, 1′-binaphthyls, that is, i) NBS-bromination to benzylic bromides, ii) treatment with sodium salt of 2-nitropropane to aldehydes, and iii) KMnO 4– oxidation to carboxylic acids.
[Sugimoto, Akira; Sumida, Ryozo; Tamai, Naoto; Inoue, Hiroo; Otsuji, Yoshio Bulletin of the Chemical Society of Japan, 1981 , vol. 54, # 11 p. 3500 - 3504]