title: Shedding light on organocatalysis-light-assisted asymmetric ion-pair catalysis for the enantioselective hydrogenation of pyrylium ions.
abstract: A new light-driven asymmetric ion-pair catalysis procedure for the metal-free enantioselective hydrogenation of in situ generated pyrylium ions from readily available chalcones was developed (see scheme). The photo-assisted Brønsted acid catalyzed procedure has broad scope and allows, for the first time, access to valuable 4H-chromenes in good yields and with excellent enantioselectivities.
authors.affiliation: Institut für Organische Chemie, RWTH Aachen, Landoltweg 1, 52074 Aachen, Germany.
authors.forename: Chien-Chi
authors.initials: CC
authors.lastname: Hsiao
authors.forename: Hsuan-Hung
authors.initials: HH
authors.lastname: Liao
authors.forename: Erli
authors.initials: E
authors.lastname: Sugiono
authors.forename: Iuliana
authors.initials: I
authors.lastname: Atodiresei
authors.forename: Magnus
authors.initials: M
authors.lastname: Rueping
keywords: asymmetric catalysis; benzopyrane; chiral ion pair; oxocarbenium ion; reduction