Mechanochemical synthesis of C-1 deuterated aldehydes and α-deutero acyloins via NHC catalysis.

α-Deutero acyloins and C-1 deuterated aromatic aldehydes are synthesized via NHC catalysed umpolung using D2O under mechanochemical conditions. The competing aldehyde deuteration and deutero-benzoin condensation are controlled by the steric hindrance of the Breslow intermediate with NHC catalysts. The mechanochemical set-up offers easy access to further deuterium-labelled building blocks.