Interplay between the Directing Group and Multifunctional Acetate Ligand in Pd-Catalyzed anti-Acetoxylation of Unsymmetrical DialkylSubstituted Alkynes
EntityUAM. Departamento de Química; UAM. Departamento de Química Orgánica
PublisherAmerican Chemical Society
10.1021/acscatal.2c00710ACS Catalysis 12.11 (2022): 6596–6605
Funded byWe thank the Ministerio de Ciencia e Innovación (MICINN) and Fondo Europeo de Desarrollo Regional (FEDER, UE) for financial support (Agencia Estatal de Investigación/Projects PGC2018-098660-B-I00 and PGC2018-094644-B-C21). J.C. and I.C. thank MECD and MINECO for an FPU fellowship and a Ramón y Cajal contract, respectively. We also acknowledge the Centro de Computación Científica of the Universidad Autónoma de Madrid for computational time. We thank Inés Manjón for generous donation of precursors for the synthesis of starting materials. We also thank the referees for their careful and insightful feedback, which helped us to improve our manuscript and to gain a better understanding of the reaction
SubjectsMultifunctional ligand; Ligand-assisted proton shuttle; Acetoxylation of alkynes; Unsymmetrical dialkyl alkynes; Metal−ligand cooperativity; Directing group; Química
Rights© 2022 The Authors
Esta obra está bajo una Licencia Creative Commons Atribución 4.0 Internacional.
The cooperative action of the acetate ligand, the 2- pyridyl sulfonyl (SO2Py) directing group on the alkyne substrate, and the palladium catalyst has been shown to be crucial for controlling reactivity, regioselectivity, and stereoselectivity in the acetoxylation of unsymmetrical internal alkynes under mild reaction conditions. The corresponding alkenyl acetates were obtained in good yields with complete levels of β-regioselectivity and anti-acetoxypalladation stereocontrol. Experimental and computational analyses provide insight into the reasons behind this delicate interplay between the ligand, directing group, and the metal in the reaction mechanism. In fact, these studies unveil the multiple important roles of the acetate ligand in the coordination sphere at the Pd center: (i) it brings the acetic acid reagent into close proximity to the metal to allow the simultaneous activation of the alkyne and the acetic acid, (ii) it serves as an inner-sphere base while enhancing the nucleophilicity of the acid, and (iii) it acts as an intramolecular acid to facilitate protodemetalation and regeneration of the catalyst. Further insight into the origin of the observed regiocontrol is provided by the mapping of potential energy profiles and distortion−interaction analysis
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Google Scholar:Corpas Pardo, Javier - Arpa González, Enrique Manuel - Lapierre, Romain - Corral Pérez, Inés - Mauleón Pérez, Pablo - Gómez Arrayas, Ramón Jesús - Carretero Gonzálvez, Juan Carlos
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