On March 30, 2020, Karmel, Caleb; Rubel, Camille Z.; Kharitonova, Elena V.; Hartwig, John F. published an article.Safety of 2-(4-Methoxythiophen-2-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane The title of the article was Iridium-Catalyzed Silylation of Five-Membered Heteroarenes: High Sterically Derived Selectivity from a Pyridyl-Imidazoline Ligand. And the article contained the following:
The steric effects of substituents on five-membered rings are less pronounced than those on six-membered rings because of the difference in bond angles. Thus, the regioselectivities of reactions of five-membered heteroarenes that occur with selectivities dictated by steric effects, such as the borylation of C-H bonds, were poor in many cases. The authors report that the silylation of five-membered-ring heteroarenes occurs with high sterically derived regioselectivity when catalyzed by the combination of [Ir(cod)(OMe)]2 (cod = 1,5-cyclooctadiene) and a phenanthroline ligand or a new pyridyl-imidazoline ligand that further increases the regioselectivity. The silylation reactions with these catalysts produce high yields of heteroarylsilanes from functionalization at the most sterically accessible C-H bonds of these rings under conditions that the borylation of C-H bonds with previously reported catalysts formed mixtures of products or products that are unstable. The heteroarylsilane products undergo cross-coupling reactions and substitution reactions with ipso selectivity to generate heteroarenes that bear halogen, aryl, and perfluoroalkyl substituents. The experimental process involved the reaction of 2-(4-Methoxythiophen-2-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane(cas: 1073339-22-6).Safety of 2-(4-Methoxythiophen-2-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane
The Article related to iridium catalyzed silylation borylation five membered heteroarene steric effects, heteroarene silylated stereoselective preparation, borane heteroarene derivative preparation, c−h functionalization, heteroarenes, iridium catalysis, regioselectivity, silylation and other aspects.Safety of 2-(4-Methoxythiophen-2-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane
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Ether – Wikipedia,
Ether | (C2H5)2O – PubChem