Absolute Asymmetric Synthesis: Viedma Ripening of [Co(bpy)3]2+ and Solvent‐Free Oxidation to [Co(bpy)3]3+

Syntheses of [Co(bpy)3](2+) yield racemic solutions because the Δ- and Λ-enantiomers are stereochemically labile. However, crystallization and attrition-enhanced deracemization can give homochiral crystal batches of either handedness in quantitative yield. Subsequently, solvent-free oxidation with bromine vapour fixes the chirality because [Co(bipy)3](3+) does not enantiomerize in solution at ambient temperature. This combination of Viedma ripening and the labile/inert Co(II)/Co(III) couple constitutes a convenient method of absolute asymmetric synthesis.