title: Enantioselective cyclopropanation of indoles: construction of all-carbon quaternary stereocenters.
abstract: The first enantioselective copper-catalyzed cyclopropanation of N-acyl indoles is described. Using carbohydrate-based bis(oxazoline) ligands (glucoBox), the products were obtained in up to 72% ee. Cyclopropanation of N-Boc 3-methyl indole yielded a product with an all-carbon quaternary stereocenter, which is a valuable building block for the synthesis of indole alkaloids: Deprotection and rearrangement gave a tricyclic hemiaminal ester in 96% ee, which was subsequently employed as a key intermediate for the synthesis of (-)-desoxyeseroline.
authors.affiliation: Institute of Organic Chemistry, Gottfried-Wilhelm-Leibniz University of Hannover, D-30167 Hannover, Germany.
authors.forename: Gülsüm
authors.initials: G
authors.lastname: Özüduru
authors.forename: Thea
authors.initials: T
authors.lastname: Schubach
authors.forename: Mike M K
authors.initials: MM
authors.lastname: Boysen
mesh_terms: D002244:Carbon / Q000737:chemistry*; D003521:Cyclopropanes / Q000737:chemistry*; D007211:Indoles / Q000737:chemistry*; D008024:Ligands; D015394:Molecular Structure; D013237:Stereoisomerism
chemical_list: D003521:Cyclopropanes; D007211:Indoles; D008024:Ligands; D002244:Carbon; C030374:indole; C030797:cyclopropane