title: Activation of carboxylic acids in asymmetric organocatalysis.
abstract: Organocatalysis, catalysis using small organic molecules, has recently evolved into a general approach for asymmetric synthesis, complementing both metal catalysis and biocatalysis. Its success relies to a large extent upon the introduction of novel and generic activation modes. Remarkably though, while carboxylic acids have been used as catalyst directing groups in supramolecular transition-metal catalysis, a general and well-defined activation mode for this useful and abundant substance class is still lacking. Herein we propose the heterodimeric association of carboxylic acids with chiral phosphoric acid catalysts as a new activation principle for organocatalysis. This self-assembly increases both the acidity of the phosphoric acid catalyst and the reactivity of the carboxylic acid. To illustrate this principle, we apply our concept in a general and highly enantioselective catalytic aziridine-opening reaction with carboxylic acids as nucleophiles.
authors.affiliation: Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr (Germany).
authors.forename: Mattia Riccardo
authors.initials: MR
authors.lastname: Monaco
authors.forename: Belén
authors.initials: B
authors.lastname: Poladura
authors.forename: Miriam
authors.initials: M
authors.lastname: Diaz de Los Bernardos
authors.forename: Markus
authors.initials: M
authors.lastname: Leutzsch
authors.forename: Richard
authors.initials: R
authors.lastname: Goddard
authors.forename: Benjamin
authors.initials: B
authors.lastname: List
mesh_terms: D000605:Amino Alcohols / Q000737:chemistry; D001388:Aziridines; D002264:Carboxylic Acids / Q000737:chemistry*; D002384:Catalysis; D018360:Crystallography, X-Ray; D008968:Molecular Conformation; D010756:Phosphoric Acids / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D000605:Amino Alcohols; D001388:Aziridines; D002264:Carboxylic Acids; D010756:Phosphoric Acids; C030242:phosphoric acid
keywords: amino alcohols; aziridines; carboxylic acids; organocatalysis; self-assembly