Description:
<jats:title>Abstract</jats:title><jats:p>We herein report our efforts to obtain a new class of systematically modified bifunctional (thio)urea‐containing quaternary ammonium salts based on easily obtainable chiral backbones. Among the different classes of catalysts that were successfully synthesized, those based on <jats:italic>trans</jats:italic>‐1,2‐cyclohexane diamine were found to be the most powerful for the asymmetric α‐fluorination of β‐keto esters. Selectivities up to 93:7 could be obtained by using only 2 mol‐% of the optimized catalyst. The importance of the bifunctional nature of these catalysts was demonstrated by control experiments using simplified monofunctional catalyst analogues, which gave almost racemic product only.</jats:p>