title: Asymmetric Synthesis of Spiropyrazolones by Sequential Organo- and Silver Catalysis.
abstract: A stereoselective one-pot synthesis of spiropyrazolones through an organocatalytic asymmetric Michael addition and a formal Conia-ene reaction has been developed. Depending on the nitroalkene, the 5-exo-dig-cyclization could be achieved by silver-catalyzed alkyne activation or by oxidation of the intermediate enolate. The mechanistic pathways have been investigated using computational chemistry and mechanistic experiments.
authors.affiliation: Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Hack
authors.affiliation: Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany.
authors.forename: Alexander B
authors.initials: AB
authors.lastname: Dürr
authors.affiliation: Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany.
authors.forename: Kristina
authors.initials: K
authors.lastname: Deckers
authors.affiliation: Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany.
authors.forename: Pankaj
authors.initials: P
authors.lastname: Chauhan
authors.affiliation: Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany.
authors.forename: Nico
authors.initials: N
authors.lastname: Seling
authors.affiliation: Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany.
authors.forename: Lukas
authors.initials: L
authors.lastname: Rübenach
authors.affiliation: Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany.
authors.forename: Lucas
authors.initials: L
authors.lastname: Mertens
authors.affiliation: Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany.
authors.forename: Gerhard
authors.initials: G
authors.lastname: Raabe
authors.affiliation: Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany.
authors.forename: Franziska
authors.initials: F
authors.lastname: Schoenebeck
authors.affiliation: Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany. enders@rwth-aachen.de.
authors.forename: Dieter
authors.initials: D
authors.lastname: Enders
keywords: Conia-ene reaction; asymmetric synthesis; organocatalysis; pyrazolones; silver catalysis