P-10 - Catalysis

A Carbene Extended ATRA Reaction

Jennifer Börger, Guojiao Wu and Axel Jacobi von Wangelin

Universität Hamburg, Martin-Luther-King-Platz 6, 20146, Hamburg, GER

The availability of stable and convenient precursors to carbenes and carbenoids has enabled the development of versatile insertion, addition, cyclization, and cross-coupling reactions based on such $\ce{C1}$-building blocks. Especially, metal-catalyzed transformations of diazo compounds have found wide applications to complex molecule syntheses. 1 This was mostly studied with porphyrin-cobalt(II) complexes which effectively translate the open-shell configuration of the metal ion through coordination of a carbene ligand into a C-centered radical (Scheme 1, top left). 2 Another reaction type with the use of of alkenes and alkynes is the atom transfer radical addition (ATRA). This class of reactions has evolved to become one of the most powerful and versatile methods for the direct 1,2-difunctionalization of alkenes and alkynes in a single operation (Scheme 1, top right) 3. We combined these two reaction types to an intermolecular, three-component radical-initiated formal successive carbon-carbon bonds formation of $\ce{TMSCHN2}$ and alkynes via the radical insertion to introduce the fluoroalkyl group (Scheme 1 bottom). 4

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Scheme 1: Merging the concepts of cobalt carbenoid reactivity with metal-catalyzed ATRA mechanism to a cobalt-catalyzed $\ce{C1}$-expanded ATRA reaction.

  1. a) H. Zollinger, Diazo Chemistry I and II; Wiley-WCH: Weinheim, Germany, 1995

  2. for selective examples: a) T. Ikeno, I. Iwakura, T. Yamada, J. Am. Chem. Soc. 2002, 124, 15152-15153. b) T. Ikeno, I. Iwakura, S. Yabushita, T. Yamada. Org. Lett. 2002, 4, 517-520; c) W. I. Dzik, X. Xu, X. P. Zhang, J. N. H. Reek, B. de Bruin, J. Am. Chem. Soc. 2010, 132, 10891-10902.

  3. a) M. S. Kharasch, E. V. Jensen, W. H. Urry, Science 1945, 102, 128; b) M. S. Kharasch, P. S. Skell, P. Fisher, J. Am. Chem. Soc. 1948, 70, 1055-1059

  4. G. Wu, J. Börger, A. Jacobi von Wangelin, Angew. Chem. Int. Ed., 2019, accepted DOI: 10.1002/anie.201909872