Asymmetric α‐Chlorination of β‐Keto Esters Using Hypervalent Iodine‐Based Cl‐Transfer Reagents in Combination with Cinchona Alkaloid Catalysts

We herein report an unprecedented strategy for the asymmetric α‐chlorination of β‐keto esters with hypervalent iodine‐based Cl‐transfer reagents using simple Cinchona alkaloid catalysts. Our investigations support an α‐chlorination mechanism where the Cinchona species serves as a nucleophilic catalyst by reacting with the chlorinating agent to generate a chiral electrophilic Cl‐transfer reagent in situ. Using at least 20 mol‐% of the alkaloid catalyst allows for good yields and enantioselectivities for a variety of different β‐keto esters under operationally simple conditions.