Catalyst-controlled selectivity in the C-H borylation of methane and ethane
Catalyst-controlled selectivity in the C-H borylation of methane and ethane
复制标题
DOI：
10.1126/science.aad9289
复制
发表时间：
2016-03-25
期刊：
影响因子：
56.9
通讯作者：
Sanford, Melanie S.
中科院分区：
文献类型：
--
作者：
Cook, Amanda K.;Schimler, Sydonie D.;Sanford, Melanie S.
与其他碳氢化合物、反应溶剂和甲烷官能化产物相比，甲烷的C-H键通常更具动力学惰性。因此，制定战略以实现甲烷的选择性功能化仍然是一项重大挑战。在这里，我们报道了在150℃，2800到3500千帕斯卡甲烷压力下，在环己烷溶剂中，过渡金属催化的甲烷与双频碳硼烷(B(2)Pin(2))的C-H硼化反应。IrRh、Rh和Ru的络合物都催化该反应。一硼甲烷和二硼甲烷的形成可根据催化剂的变化进行调节，其中Ru络合物提供了最高的CH(3)Bpin与CH2(Bpin)(2)的比率。尽管环己烷的相对浓度很高，但观察到少量的硼化环己烷产物。此外，这三种金属络合物均能催化甲烷的硼化反应，对乙烷的选择性为3.5：1。
The C-H bonds of methane are generally more kinetically inert than those of other hydrocarbons, reaction solvents, and methane functionalization products. Thus, developing strategies to achieve selective functionalization of CH4 remains a major challenge. Here, we report transitionmetal-catalyzed C-H borylation ofmethane with bis-pinacolborane (B(2)pin(2)) in cyclohexane solvent at 150 degrees C under 2800 to 3500 kilopascals of methane pressure. Iridium, rhodium, and ruthenium complexes all catalyze the reaction. Formation of mono-versus diborylatedmethane is tunable as a function of catalyst, with the ruthenium complex providing the highest ratio of CH(3)Bpin to CH2 (Bpin)(2). Despite the high relative concentration of cyclohexane, minimal quantities of borylated cyclohexane products are observed. Furthermore, all three metal complexes catalyze borylation of methane with >3.5:1 selectivity over ethane.