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

Cinchona alkaloid-based thiourea catalysts (1a and 1b) 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.