title: Catalytic asymmetric Tamura cycloadditions.
abstract: In the presence of a novel, tert-butyl-substituted squaramide-based catalyst, enolizable anhydrides react with alkylidene oxindoles to generate spirooxindole products of significant synthetic interest with excellent enantio- and diastereocontrol. The methodology is of wide scope and encompasses both homophthalic and glutaconic anhydride derivatives, which lead to structurally diverse products. Glutaconic acid-derived anhydrides undergo a clean post-cyclization decarboxylation process which is not a feature of reactions involving homophthalic acid-derived anhydrides. The unusual influence of reaction temperature on diastereocontrol has been probed, with reactions occurring at 30 °C and -30 °C delivering products epimeric at one stereocenter only, in near optical purity.
authors.affiliation: Trinity Biomedical Sciences Institute, School of Chemistry, The University of Dublin, Trinity College, Dublin 2 (Ireland).
authors.forename: Francesco
authors.initials: F
authors.lastname: Manoni
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Connon
mesh_terms: D000577:Amides / Q000737:chemistry*; D002384:Catalysis; D003500:Cyclization; D007211:Indoles / Q000138:chemical synthesis* / Q000737:chemistry; D008958:Models, Molecular; D015394:Molecular Structure; D013141:Spiro Compounds / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D000577:Amides; D007211:Indoles; D013141:Spiro Compounds
keywords: asymmetric catalysis; cycloaddition; organocatalysis; spirocompounds; synthetic methods