Karmel, Caleb; Rubel, Camille Z.; Kharitonova, Elena V.; Hartwig, John F. published an article in 2019, the title of the article was Iridium-catalyzed silylation of five-membered heteroarenes: high sterically derived selectivity from a pyridyl-imidazoline ligand.Name: 2-(4-Methoxythiophen-2-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane And the article contains the following content:
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 that occur with selectivities dictated by steric effects, such as the borylation of C-H bonds, have been poor in many cases. We 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 and a phenanthroline ligand or a new pyridylimidazoline 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).Name: 2-(4-Methoxythiophen-2-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane
The Article related to heteroarene heptamethyltrisiloxane bispinacolatodiboron iridium catalyst pyridyl imidazoline ligand, regioselective chemoselective silylation borylation hiyama coupling, Heterocyclic Compounds (One Hetero Atom): Other 5-Membered Rings and other aspects.Name: 2-(4-Methoxythiophen-2-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane
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