Shielding effects of the diphenylmethanol substituent in certain anisole derivatives: a method for determination of the site of metallation

Abstract

A potentially valuable tool for isomer identification of lithio-aromatics consists of condensation of the lithio-intermediate with benzophenone and examination of the effect on the chemical shift of various alkyl substituent protons in the molecule: alkyl protons adjacent to the diphenylmethanol substituent invariably experience a significant upfield shift.