Diastereoselective and Enantioselective Michael Addition Reactions of Ketones and Aldehydes to Nitro Olefins Catalyzed by C2‐Symmetric Axially‐Unfixed Biaryl‐Based Organocatalysts Derived from Enantiopure α‐Proline

Abstract

AbstractA new class of axially‐unfixed biaryl‐based pyrrolidines with C2‐symmetry were designed and synthesized by using enantiopure α‐proline as a chiral source. These bifunctional organocatalys provided Michael adducts in high chemical yields (up to 99 %) and with excellent stereoselectivities (up to 99:1 dr and 96 % ee) in the direct Michael addition reactions of a variety of ketones and aldehydes to nitro olefins. The transition states were proposed to clarify the stereochemical course of the examined reactions.