N‐Heterocyclic Carbene Acyl Anion Organocatalysis by Ball‐Milling

The ability to conduct N‐heterocyclic carbene‐catalysed acyl anion chemistry under ball‐milling conditions is reported for the first time. This process has been exemplified through applications to intermolecular‐benzoin, intramolecular‐benzoin, intermolecular‐Stetter and intramolecular‐Stetter reactions including asymmetric examples and demonstrates that this mode of mechanistically complex organocatalytic reaction can operate under solvent‐minimised conditions. Having a ball: The ability to conduct mechanistically complex N‐heterocyclic carbene‐catalysed acyl anion chemistry under ball‐milling conditions is reported for the first time. This process is exemplified through applications to intermolecular‐benzoin, intramolecular‐benzoin, intermolecular‐Stetter and intramolecular‐Stetter reactions including asymmetric examples.