title: Light-Driven Enantioselective Organocatalytic β-Benzylation of Enals.
abstract: A photochemical organocatalytic strategy for the direct enantioselective β-benzylation of α,β-unsaturated aldehydes is reported. The chemistry capitalizes upon the light-triggered enolization of 2-alkyl-benzophenones to afford hydroxy-o-quinodinomethanes. These fleeting intermediates are stereoselectively intercepted by chiral iminium ions, transiently formed upon condensation of a secondary amine catalyst with enals. Density functional theory (DFT) studies provided an explanation for why the reaction proceeds through an unconventional Michael-type addition manifold, instead of a classical cycloaddition mechanism and subsequent ring-opening.
authors.affiliation: ICIQ-Institute of Chemical Research of Catalonia the Barcelona Institute of Science and Technology, Avenida Països Catalans 16, 43007, Tarragona, Spain.
authors.forename: Luca
authors.identifier: 0000-0003-0423-9628
authors.initials: L
authors.lastname: Dell'Amico
authors.affiliation: ICIQ-Institute of Chemical Research of Catalonia the Barcelona Institute of Science and Technology, Avenida Països Catalans 16, 43007, Tarragona, Spain.
authors.forename: Victor M
authors.initials: VM
authors.lastname: Fernández-Alvarez
authors.affiliation: Departament de Quimica, Universitat Autònoma de Barcelona, 08193, Bellaterra, Spain.|ICIQ-Institute of Chemical Research of Catalonia the Barcelona Institute of Science and Technology, Avenida Països Catalans 16, 43007, Tarragona, Spain.
authors.forename: Feliu
authors.initials: F
authors.lastname: Maseras
authors.affiliation: ICREA-Catalan Institution for Research and Advanced Studies, Passeig Lluís Companys 23, 08010, Barcelona, Spain.|ICIQ-Institute of Chemical Research of Catalonia the Barcelona Institute of Science and Technology, Avenida Països Catalans 16, 43007, Tarragona, Spain.
authors.forename: Paolo
authors.identifier: 0000-0001-8722-4602
authors.initials: P
authors.lastname: Melchiorre
keywords: asymmetric catalysis; benzylation; organocatalysis; photochemistry; synthetic methods