C–H Borylation Catalysts that Distinguish Between Similarly Sized Substituents Like Fluorine and Hydrogen
作者:Susanne L. Miller、Ghayoor A. Chotana、Jonathan A. Fritz、Buddhadeb Chattopadhyay、Robert E. Maleczka、Milton R. Smith
DOI:10.1021/acs.orglett.9b02299
日期:2019.8.16
By modifying ligand steric and electronic profiles it is possible to C–H borylate ortho or meta to substituents in aromatic and heteroaromatic compounds, where steric differences between accessible C–H sites are small. Dramatic effects on selectivities between reactions using B2pin2 or 4,4,5,5-tetramethyl-1,3,2-dioxaborolane (HBpin) are described for the first time. Judicious ligand and borane combinations
通过修改配体空间和电子分布,可以将 C-H 硼酸化为邻位或间位芳族和杂芳族化合物中的取代基,其中可及 C-H 位点之间的空间差异很小。首次描述了使用 B 2 pin 2或 4,4,5,5-tetramethyl-1,3,2-dioxaborolane (HBpin)对反应之间选择性的显着影响。明智的配体和硼烷组合在底物上提供高度区域选择性的 C-H 硼酸化,而典型的硼酸化方案提供的选择性很差。