Enantioselective Iridium-Catalyzed Allylation of Nitroalkanes: Entry to β-Stereogenic α-Quaternary Primary Amines
Woo‐Ok Jung, Binh Khanh, Brian J. Spinello, Zachary J. Dubey, Seung Wook Kim, Craig E. Stivala, Jennifer E. Klomp, Peng Liu, Michael J. Krische
Abstract
The first systematic study of simple nitronate nucleophiles in iridium-catalyzed allylic alkylation is described. Using a tol-BINAP-modified π-allyliridium C,O-benzoate catalyst, α,α-disubstituted nitronates substitute racemic branched alkyl-substituted allylic acetates, thus providing entry to β-stereogenic α-quaternary primary amines. DFT calculations reveal early transition states that render the reaction less sensitive to steric effects and distinct trans-effects of diastereomeric chiral-at-iridium π-allyl complexes that facilitate formation of congested tertiary–quaternary C–C bonds.
Topics & Concepts
StereocenterChemistryEnantioselective synthesisIridiumCatalysisQuaternaryPrimary (astronomy)Organic chemistryCombinatorial chemistryAstronomyPaleontologyPhysicsBiologyAsymmetric Hydrogenation and CatalysisChemical Synthesis and AnalysisAsymmetric Synthesis and Catalysis