Álvarez, MaríaBesora, MaríaMolina González, FranciscoMaseras, FeliuRodríguez Belderraín, TomásPérez Romero, Pedro José2021-04-202021-04-202021-03Álvarez, M., Besora, M., Molina, F., Maseras, F., Belderrain, T. R., & Pérez, P. J. (2021). Two Copper-Carbenes from One Diazo Compound. Journal of the American Chemical Society, 143(12), 4837–4843. https://doi.org/10.1021/jacs.1c014830002-78631520-5126 (electrónico)http://hdl.handle.net/10272/19704Many transition-metal complexes MLn decompose diazo compounds N2-CR1R2 generating metal-carbenes LnM-CR1R2 which transfer the carbene group to other substrates, constituting an important tool in organic synthesis. All previous reports have shown that the CR1R2 fragment at the metal-carbene remains intact from the parent diazo compound. Herein we report the detection and isolation of a monosubstituted copper carbene where the CR1R2 ligand has undergone a modification from the initial diazo reagent. When TpMsCu(THF) (TpMs = hydrotris(3-mesityl)pyrazolylborate ligand) was reacted with N,N-diethyl diazoacetamide [N2-C(H)(CONEt2)], the stable copper carbene TpMsCu-C(H)(NEt2) was isolated, resulting from a decarbonylation process, with carbon monoxide being trapped as TpMsCu(CO). The simultaneous observation of products derived from the intramolecular carbene insertion reaction into C–H bonds demonstrates that the expected TpMsCu-C(H)(CONEt2) complex is also formed. Experimental data, DFT calculations, and microkinetic models allow us to propose that the latter undergoes CO loss en route to the former.engAttribution 4.0 Internationalhttp://creativecommons.org/licenses/by/4.0/Metal carbenesCopper carbenesDiazo compoundsCarbene decarbolylationMicrokinetic studiesjournal article10.1021/jacs.1c01483open access23 Química