Mechanisms and Origins of Regioselectivity in Rare-Earth-Catalyzed C–H Functionalization of Anisoles and Thioanisoles

Inorganic Chemistry, Год журнала: 2025, Номер unknown

Опубликована: Март 12, 2025

The direct catalytic C–H functionalization of aromatic compounds such as anisoles and thioanisoles is great interest significance. However, achieving precise regioselectivity remains a major challenge. In this study, we conducted comprehensive density functional theory calculations to explore the mechanisms rare-earth-catalyzed regioselective alkylation, borylation, silylation anisole thioanisole. results reveal that in cationic alkylation systems, alkene insertion step follows substrate-assisted mechanism, which an additional substrate molecule acts ligand facilitate transformation. neutral borylation although mononuclear hydride species readily dimerize into binuclear due thermodynamic stability, process predominantly proceeds via pathway. Furthermore, origins were thoroughly elucidated. A detailed analysis electronic steric effects related transition states reveals that, for anisole, primarily governed by ring strain. Since α-C(sp3)–H activation involves formation highly strained three-membered ring, reaction preferentially occurs at ortho-C(sp2)–H site, forming less four-membered ring. contrast, thioanisole, play decisive role, driving more negatively charged α-C(sp3) site stronger metal–carbon interactions.

Язык: Английский

Asymmetric Catalytic (3 + 2) Cyclization and Sequential Reaction to Construct Dihydrofuran- and Azepine-Based Spirooxindoles

Organic Letters, Год журнала: 2025, Номер unknown

Опубликована: Фев. 22, 2025

The enantioselective formal (3 + 2) cyclization and sequential reaction of 2-malononitrile-substituted oxindoles with benzaldehydes ortho-aminobenzaldehydes were achieved by chiral N,N′-dioxide/metal complex Lewis acid catalysts. This protocol supplies facile efficient access to highly functionalized dihydrofuran- azepine-based spirooxindoles. Based on the control experiments deuterium labeling studies, interconversion diastereomeric intermediates under conditions reversible 1,5-H transfer step disclosed.

Язык: Английский

Overlooked Ligand Role of Pyridine Substrate in Site Selectivity of Rare-Earth-Catalyzed C–H Alkylation with Alkenes

Inorganic Chemistry, Год журнала: 2025, Номер unknown

Опубликована: Апрель 11, 2025

The rare-earth-catalyzed C-H alkylation of heteroatom-containing substrates with alkenes has been extensively studied over the past decade. Traditionally, those have regarded primarily as reactants in these reactions. In this study, mechanism 2-ethylpyridine styrene was investigated by DFT calculations, revealing often-overlooked ligand effect pyridine substrates. Our findings demonstrate that substrates, acting ligands, play a pivotal role modulating site selectivity during activation. These results enhance our understanding rare-earth catalysis and provide valuable insights into its versatile reactivity, offering novel perspective on dual roles (both reactant ligand) which are widely used functionalization

Язык: Английский