Catalytic borylation of methane

• Published in: Science (American Association for the Advancement of Science) Vol. 351; no. 6280; pp. 1424 - 1427
• Main Authors: Smith, Kyle T., Berritt, Simon, González-Moreiras, Mariano, Ahn, Seihwan, Smith, Milton R., Baik, Mu-Hyun, Mindiola, Daniel J.
• Format: Journal Article
• Language: English
• Published: United States American Association for the Advancement of Science 25.03.2016; The American Association for the Advancement of Science
• Subjects: Boron; Catalysis; Catalysts; Chemical reactions; High temperature; Hydrocarbons; Inhalants; Iridium; Methane; Rhodium; Ruthenium; Solvents
• ISSN: 0036-8075; 1095-9203; 1095-9203
• DOI: 10.1126/science.aad9730

Despite steady progress in catalytic methods for the borylation of hydrocarbons, methane has not yet been subject to this transformation. Here we report the iridium-catalyzed borylation of methane using bis(pinacolborane) in cyclohexane solvent. Initially, trace amounts of borylated products were detected with phenanthroline-coordinated Ir complexes. A combination of experimental high-pressure and high-throughput screening, and computational mechanism discovery techniques helped to rationalize the foundation of the catalysis and identify improved phosphine-coordinated catalytic complexes. Optimized conditions of 150°C and 3500-kilopascal pressure led to yields as high as ~52%, turnover numbers of 100, and improved chemoselectivity for monoborylated versus diborylated methane.