Cinchona alkaloid catalysis thiourea-based

The catalytic potential of base functionalities has been referred to in the previous chapter (see Sect. 7.4), wherein the interplay between an acidic (thio-)urea and a basic amine separated by a chiral linker was shown to enable the simultaneous activation of both the electrophile and nucleophile. In addition to such brfunctional thiourea-containing acid-base catalysts, chiral catalysts containing Lewis or Br0nsted-) base functionality as the sole catalyticaUy active group as weU as those having another H-bond donor like a hydroxy group e.g. Cinchona alkaloids) have found widespread applications in asymmetric catalysis (443-449). 

Connon SJ. Asymmetric catalysis with bifunctional cinchona alkaloid-based urea and thiourea organocatalysts. Chem. Commun. 2008 22 2499-2510. 

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