title: Diazo- and transition-metal-free C-H insertion: a direct synthesis of β-lactams.
abstract: Carbene intermediates are very useful species for a range of reactions including C-H insertions and cycloadditions. They are most commonly generated by metal-catalyzed release of nitrogen gas from diazo precursors. Herein, we present a novel C-H insertion of simple β-ketoamide substrates, through reaction with (diacetoxyiodo)benzene (DIB) in the presence of a base. This unprecedented transformation bypasses the use of either diazo precursors or metal catalysts and directly delivers β-lactam products by an iodonium ylide, in a single step under mild conditions. Mechanistic studies support the intermediacy of a free singlet carbene of unique reactivity and selectivity.
authors.affiliation: Instituto de Investigação do Medicamento (iMed.ULisboa), Faculty of Pharmacy, University of Lisbon, Av. Prof. Gama Pinto, 1649-019 (Portugal).
authors.forename: Luis F R
authors.initials: LF
authors.lastname: Gomes
authors.forename: Luís F
authors.initials: LF
authors.lastname: Veiros
authors.forename: Nuno
authors.initials: N
authors.lastname: Maulide
authors.forename: Carlos A M
authors.initials: CA
authors.lastname: Afonso
mesh_terms: D000577:Amides / Q000138:chemical synthesis / Q000737:chemistry*; D001555:Benzene Derivatives / Q000138:chemical synthesis / Q000737:chemistry*; D008697:Methane / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry; D013816:Thermodynamics; D047090:beta-Lactams / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D000577:Amides; D001555:Benzene Derivatives; D047090:beta-Lactams; C520957:beta-ketoamide; C030011:carbene; D008697:Methane
keywords: CH insertion; carbenes; iodonium ylides; lactams; reaction mechanism