title: The Rhodium(II) Carbenoid Cyclization-Cycloaddition Cascade of alpha-Diazo Dihydroindolinones for the Synthesis of Novel Azapolycyclic Ring Systems.
abstract: Tandem carbonyl ylide formation-1,3-dipolar cycloaddition of alpha-diazo N-acetyl-tetrahydro-beta-carbolin-1-one derivatives occur efficiently in the presence of a dirhodium catalyst to afford bimolecular cycloadducts in high yield. The Rh(II)-catalyzed reaction also takes place intramolecularly to give products derived from trapping of the carbonyl ylide dipole with a tethered alkene. The power of the intramolecular cascade sequence is that it rapidly assembles a pentacyclic ring system containing three new stereocenters and two adjacent quaternary centers stereospecifically in a single step and in high yield.
authors.affiliation: Department of Chemistry, Emory University, Atlanta, GA 30322, USA.
authors.forename: Dylan B
authors.initials: DB
authors.lastname: England
authors.forename: James M
authors.initials: JM
authors.lastname: Eagan
authors.forename: Gokce
authors.initials: G
authors.lastname: Merey
authors.forename: Olcay
authors.initials: O
authors.lastname: Anac
authors.forename: Albert
authors.initials: A
authors.lastname: Padwa