Optical activity in the 1,1′-binaphthyl series. Energy barriers to racemisation of 8-substituted 1,1′-binaphthyls

Abstract

8-Methyl- and 8-hydroxymethyl-1,1′-binaphthyl have been synthesised in the optically active state, and their Arrhenius parameters and transition-state theory (Eyring) functions for racemisation in solution determined. Optically active 8-bromomethyl-1,1′-binaphthyl has also been prepared, but velocity constants for its racemisation could not be determined because it decomposes at the temperatures required. Optical stabilities of 1,1′-binaphthyl substituted in the 8-position by –CO₂H, –CO₂Me, –CH₂·OH, and –CH₃ are compared within the series, and with those of the corresponding 8,8′-disubstituted compounds and of 1,1′-binaphthyl itself.