Axially Chiral Trifluoromethylbenzimidazolylbenzoic Acid: A Chiral Derivatizing Agent for α-Chiral Primary Amines and Secondary Alcohols To Determine the Absolute Configuration

Abstract

Racemic 2-(2-trifluoromethyl)-1<i>H</i>-benzo[<i>d</i>]imidazol-1-yl)benzoic acid (TBBA) was synthesized in three steps from 1-fluoro-2-nitrobenzene. Target (<i>P</i>)- and (<i>M</i>)-TBBA atropisomers were stable with a racemization barrier above 30 kcal/mol. As a chiral derivatizing agent, TBBA showed much higher differences in chemical shifts (Δδ^PM) than the conventional Mosher's acid.