A Catalytic Method for the Enantioselective Synthesis of α‐Quaternary Ketones, α‐Ketoesters and Aldehydes
Emilie Wheatley, Joseph M. Zanghi, Miles M. Mason, Simon J. Meek
Abstract
A practical method for the efficient and enantioselective preparation of versatile ketones and aldehydes that contain an α-quaternary stereocenter is described. Reactions utilize simple carboxylic acid or ester starting materials, a monodentate chiral phosphine, and afford a variety of aryl, alkenyl, alkynyl, and alkyl-substituted ketone and aldehyde products in 25-94 % yield and 90 : 10 to >99 : 1 enantiomeric ratio. Reactions proceed by acyl substitution with in situ formed chiral allylic nucleophiles, and display selectivity and conversion dependence on a protic additive. The utility of the approach is demonstrated through several product transformations.
Topics & Concepts
Enantioselective synthesisStereocenterAldehydeChemistryKetoneOrganic chemistryYield (engineering)PhosphineAllylic rearrangementNucleophileEnantiomeric excessCatalysisArylCombinatorial chemistryAlkylMaterials scienceMetallurgyAsymmetric Synthesis and CatalysisAsymmetric Hydrogenation and CatalysisAdvanced Synthetic Organic Chemistry