title: Enantioselective organocatalytic hydride reduction.
abstract: The first enantioselective organocatalytic hydride reduction has been accomplished. The use of iminium catalysis has provided a new organocatalytic strategy for the enantioselective reduction of beta,beta-substituted alpha,beta-unsaturated aldehydes to generate beta-stereogenic aldehydes. The use of imidazolidinone 2 as the asymmetric catalyst has been found to mediate the transfer of hydrogen to a large class of enal substrates from ethyl Hantzsch ester. The capacity of catalyst 2 to accelerate E-Z isomerization prior to selective E-olefin reduction allows the implementation of geometrically impure enals in this operationally simple protocol.
authors.affiliation: Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA.
authors.forename: Stéphane G
authors.initials: SG
authors.lastname: Ouellet
authors.forename: Jamison B
authors.initials: JB
authors.lastname: Tuttle
authors.forename: David W C
authors.initials: DW
authors.lastname: MacMillan
mesh_terms: D000447:Aldehydes / Q000737:chemistry*; D004095:Dihydropyridines / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry*; D048289:Imidazolidines / Q000737:chemistry*; D007097:Imines / Q000737:chemistry; D008958:Models, Molecular; D010084:Oxidation-Reduction; D011392:Proline / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D000447:Aldehydes; D004095:Dihydropyridines; D048289:Imidazolidines; D007097:Imines; D006859:Hydrogen; D011392:Proline