Methyl proton resonance in nuclear magnetic resonance spectra of 2,2′- and 8,8′-dimethyl-1,1′-binaphthyls. The optical stability of (+)-2,2′-dimethyl-1,1′-binaphthyl

Abstract

(+)-2,2′-Dimethyl-1,1′-binaphthyl has resisted racemisation in solution. This contrasts with 8,8′-dimethyl-1,1′-binaphthyl which is optically labile. Methyl proton signals in the n.m.r. spectra of these compounds can be used to throw light on their conformations in the ground state.