Scandium Trifluoromethanesulfonate as Catalyst in the Hydrogen/Deuterium Exchange of 1,3,5-Trimethoxybenzene: Evidence for a Direct Interaction of Scandium with the Aromatic Ring

Scandium trifluoromethanesulfonate in CD3OD is a very active catalyst for hydrogen/deuterium exchange at the aromatic nucleus of 1,3,5-trimethoxybenzene. The very low proticity of the system, spectrophotometric evidence, and easy iodination of the substrate point to the formation of a transient unprecedented arylscandium species as a plausible intermediate of the reaction.