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Updated: Apr 20, 2026

Efficient Synthesis of All-Carbon Quaternary Centers via the Conjugate Addition of Functionalized Monoorganozinc Bromides
Published on: May 26, 2019
Diazo- and transition-metal-free C-H insertion: a direct synthesis of β-lactams
Luis F R Gomes1, Luís F Veiros, Nuno Maulide
1Instituto de Investigação do Medicamento (iMed.ULisboa), Faculty of Pharmacy, University of Lisbon, Av. Prof. Gama Pinto, 1649-019 (Portugal).
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.
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