title: Asymmetric Synthesis of Spirobenzazepinones with Atroposelectivity and Spiro-1,2-Diazepinones by NHC-Catalyzed [3+4] Annulation Reactions.
abstract: A strategy for the NHC-catalyzed asymmetric synthesis of spirobenzazepinones, spiro-1,2-diazepinones, and spiro-1,2-oxazepinones has been developed via [3+4]-cycloaddition reactions of isatin-derived enals (3C component) with in-situ-generated aza-o-quinone methides, azoalkenes, and nitrosoalkenes (4atom components). The [3+4] annulation strategy leads to the seven-membered target spiro heterocycles bearing an oxindole moiety in high yields and excellent enantioselectivities with a wide variety of substrates. Notably, the benzazepinone synthesis is atroposelective and an all-carbon spiro stereocenter is generated.
authors.affiliation: Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany.
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
authors.affiliation: Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany.
authors.forename: Sun
authors.initials: S
authors.lastname: Li
authors.affiliation: Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany.
authors.forename: Marcus
authors.initials: M
authors.lastname: Blümel
authors.affiliation: Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany.
authors.forename: Arne R
authors.initials: AR
authors.lastname: Philipps
authors.affiliation: Institute of Inorganic Chemistry, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany.
authors.forename: Ai
authors.initials: A
authors.lastname: Wang
authors.affiliation: Department of Chemistry, Nanoscience Center, University of Jyvaskyla, 40014, JYU, Finland.
authors.forename: Rakesh
authors.initials: R
authors.lastname: Puttreddy
authors.affiliation: Department of Chemistry, Nanoscience Center, University of Jyvaskyla, 40014, JYU, Finland.
authors.forename: Kari
authors.initials: K
authors.lastname: Rissanen
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: 1,2-diazepinone; N-heterocyclic carbene; asymmetric synthesis; benzazepinone; spiro compound