2,2′-Dihydroxybenzil: A Stereodynamic Probe for Primary Amines Controlled by Steric Strain

A rational approach for generating 1,1′-binaphthalene-like axial chirality of a small organic receptor, 2,2′-dihydroxybenzil is presented. The receptor combines with 2 equiv of monodentate primary amines to form a diimine, of which axial chirality is controlled by steric strain with moderate (1.4:1) to good (4.7:1) stereoselectivity. The observed circular dichroism (CD) spectra have been closely simulated by TD-DFT computations and can be used for determining the absolute chirality and enantiomeric excess of primary amines.