Deracemization of a Racemic Compound by Using Tailor-Made Additives.

Viedma ripening is a process that combines abrasive grinding of a slurry of crystals with solution-phase racemization, resulting in solid-phase deracemization. One of the major disadvantages of Viedma ripening is that the desired compound needs to crystallize as a racemic conglomerate, accounting for only 5-10 % of all chiral molecules. Herein, we show that use of a chiral additive causes deracemization under conditions, in which the compound normally crystallizes as a racemic compound. Although this concerns a single example, it is envisioned that through this new approach the scope of Viedma ripening can be significantly expanded.