Substituent effect of substrates on cucurbit[8]uril-catalytic oxidation of aryl alcohols

• Two series of benzylic alcohols have been employed to investigate the Q[8]-catalytic oxidation with IBX.
• The electronic and structure effect on the supramolecular catalysis of Q[8] has been discussed.
• A plausible mechanism of this supramolecular catalysis has been proposed.

Based on the formation of the ternary host–guest inclusion complex between veratryl alcohol, o-iodoxybenzoic acid (IBX) and cucurbit[8]uril (Q[8]), the effect of substrate substituents on the IBX oxidation of aryl alcohols to the corresponding aldehyde subject to supramolecular catalysis by Q[8] in aqueous solvent is described. Aryl alcohols with different substituent effect on electron, for example, 2,3,4-methoxybenzyl alcohols and 2,3,4-pyridinemethanol hydrochlorides, have been subjected to the procedure for IBX oxidizing in the absence and presence of Q[8] at room temperature. The catalytic ability of Q[8] reveals that the electronic effect of the substituent on the α-carbon of the aryl alcohol is crucial to the Q[8]-catalytic oxidation, and the supramolecular catalysis of Q[8] is mechanistically suggested to contribute to the alcohols with mainly negative inductive effect of substituent.

Based on the host–guest interaction between veratryl alcohol, o-iodoxybenzoic acid and cucurbit[8]uril (Q[8]), the substituent effect of substrate on the IBX oxidation of aryl alcohol, 2,3,4-methoxybenzyl alcohols and 2,3,4-pyridinemethanol hydrochlorides, to corresponding aldehyde with the supramolecular catalysis of Q[8] in aqueous solvent is described.Figure optionsDownload high-quality image (86 K)Download as PowerPoint slide