Regioselectivity in the acylation of methylhydroquinone dimethyl ether: an unprecedented case of indirect steric hindrance

The origin of the highly regioselective acylation of methylhydroquinone dimethyl ether was investigated using geometry minimization (ab initio and DFT) and NOE spectroscopic measurements. The theoretical and experimental results were consistent with the indirect participation of the aromatic methyl group in blocking the electrophile attack at position 3 of the aromatic ring.