Postils, VerònicaRodríguez, MònicaSabenya, GerardConde Alcántara, Ana IsabelDíaz Requejo, María MarPérez Romero, Pedro JoséCostas, MiquelSolà, MiquelLuis, Josep M.2019-02-132019-02-132018Postils, V., Rodríguez, M., Sabenya, G., Conde, A., Díaz-Requejo, M. M., Pérez, P. J., Costas, M., Solà, M., Luis, J. M. (2018). Mechanism of the Selective Fe-Catalyzed Arene Carbon–Hydrogen Bond Functionalization. ACS Catalysis, 8(5), 4313-4322. https://doi.org/10.1021/acscatal.7b039352155-5435http://hdl.handle.net/10272/15970The complete chemoselective functionalization of aromatic C(sp(2))-H bonds of benzene and alkyl benzenes by carbene insertion from ethyl diazoacetate was unknown until the recent discovery of an iron-based catalytic system toward such transformation. A Fe(II) complex bearing the pytacn ligand (pytacn = L1 = 1-(2-pyridylmethyl)-4,7-dimethyl-1,4,7-triazacyclononane) transferred the CHCO2Et unit exclusively to the C(sp(2))-H bond. The cycloheptatriene compound commonly observed through Buchner reaction or, when employing alkyl benzenes, the corresponding derivatives from C(sp(3))-H functionalization are not formed. We herein present a combined experimental and computational mechanistic study to explain this exceptional selectivity. Our computational study reveals that the key step is the formation of an enol-like substrate, which is the precursor of the final insertion products. Experimental evidences based on substrate probes and isotopic labeling experiments in favor of this mechanistic interpretation are provided.engAtribución-NoComercial-SinDerivadas 3.0 Españahttp://creativecommons.org/licenses/by-nc-nd/3.0/es/Carbene transferIron catalysisC-H activationC(sp(2))-H functionalizationDFT calculationsjournal article10.1021/acscatal.7b03935open access