Plant Process for the Preparation of Cinchona Alkaloid-Based Thiourea Catalysts

Cinchona alkaloid-based thiourea catalysts (<b>1a</b> and <b>1b</b>) belong to an important class of bifunctional organocatalysts, which has been widely used for a variety of asymmetric reactions. The commercial availability of these catalysts is sporadic, and limited to sub-gram quantities. Herein is described a general, scalable, and practicable process for the preparation of these catalysts that was used to synthesize more than 14 kg of catalyst per batch