Direct Synthesis of Cyclopropanes from gem-Dialkyl Groups through Double C-H Activation
Antonin Clemenceau, Pierre Thesmar, Maxime Gicquel, Alexandre Le Flohic and Olivier Baudoin*
*Department of Chemistry, University of Basel, St. Johanns-Ring 19, CH-4056 Basel, Switzerland, Email: olivier.baudoinunibas.ch
A. Clemenceau, P. Thesmar, M. Gicquel, A. Le Flohic, O. Baudoin, J. Am. Chem. Soc., 2020, 142, 15355-15361.
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An intramolecular coupling of two C-H bonds on gem-dialkyl groups is accessible using aryl bromide or triflate precursors and the 1,4-Pd shift mechanism. The use of pivalate as the base was found to be crucial to divert the mechanistic pathway toward the cyclopropane instead of the previously obtained benzocyclobutene product.
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Synthesis of Benzocyclobutenes by Palladium-Catalyzed C-H Activation of Methyl Groups: Method and Mechanistic Study
M. Chaumontet, R. Piccardi, N. Audic, J. Hitce, J.-L. Peglion, E. Clot, O. Baudoin, J. Am. Chem. Soc., 2008, 130, 15157-15166.