Asymmetric Aziridination of Allylic Carbamates Using Ion‐Paired Rhodium Complexes and Extrapolation to C─H Amination of Phenethyl Carbamates

Abstract

Abstract Aziridination of alkenes is an important route to chiral nitrogen‐containing building blocks. Here, we report that carbamate‐functionalized allylic alcohols undergo highly enantioselective aziridination using achiral dimeric Rh(II, II) complexes that are ion‐paired with cinchona alkaloid‐derived chiral cations. The aziridine‐containing products are amenable to a variety of further reactions to generate useful groupings of functionality. Furthermore, we show that the carbamate group is effective for directing highly enantioselective benzylic C─H amination when it is appended to phenethyl alcohols. Intermolecular C─H amination of phenethyl alcohol derivatives has proven highly challenging to achieve asymmetrically yet it gives rise to valuable β‐amino alcohols. Both processes result in rapid access to versatile, highly enantioenriched small molecule building blocks for synthesis and highlight the effectiveness and generality of this chiral cation‐based strategy for asymmetric catalysis. We report studies that probe important structural features of the chiral cation and demonstrate that the ion‐paired complexes can be formed from their individual components without a separate isolation step.