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Benzylic C–H Borylation on Ceria-Supported Nickel Hydroxides
C(sp3)–H Selective Benzylic Borylation by In Situ Reduced Ultrasmall Ni Species on CeO2 .
ACS Catal. 2021;
Nickel hydroxides supported on CeO2 (Ni(OH) x /CeO2), prepared by mixing NiCl·6H2O and CeO2 in H2O (pH = 10) (eq. 1), catalyzed the benzylic C–H borylation of alkylarenes or diphenylmethanes with pinacolborane to give the corresponding benzylic boronates (eq. 2). In the reaction of methylarenes, gem-diborylated products were obtained as the main products (eq. 3). The monoborylation of methylarenes was also achieved by using the catalyst pretreated with HBpin and with the methylarene as the solvent (eq. 4).
Ni(OH)x/CeO2 was characterized by means of XANES XPS, EXAFS, HAADF-STEM, STEM-EDS, XRD, and ICP-AES analyses. A hot-filtration experiment suggested that the reaction occurred heterogeneously.
20 April 2021 (online)
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