Organic reactions under high pressure : I. Pressure and solvent effects on the migratory aptitude of o-anisyl group

Abstract

The migratory aptitude of the o-anisyl group in the pinacol rearrrangement of 2, 2'-dimethoxybenzopinacol is changed by pressure and solvents. The increasing pressure retards the migration of the o-anisyl group in acetic acid and acetonitrile. And the migratory aptitude increases with the changes of solvents in the order of acetic acid <acetonitrile <toluene. These observations indicate that the migration of the o-anisyl group brings about higher degree of desolvation than the migration of the phenyl group. This is attributable to steric inhibition of solvation and the difference of charge distribution in the two transition states.