251933-26-3Relevant articles and documents
Direct C-H photoarylation of diazines using aryldiazonium salts and visible-light
Silva, Rodrigo C.,Villela, Lucas F.,Brocksom, Timothy J.,De Oliveira, Kleber T.
, p. 31115 - 31122 (2020/09/23)
In this study, direct C-H photoarylation of pyrazine with aryldiazonium salts under visible-light irradiation (blue-LEDs) is described, and additional examples including photoarylations of pyrimidine and pyridazine are also covered. The corresponding aryl-diazines were prepared in yields up to 84% only by mixing and irradiating the reaction with no need for an additional photocatalyst. We demonstrate the efficacy of this protocol by the scope with electron-donor, -neutral, and -withdrawing groups attached at the ortho, meta, and para positions of the aryldiazonium salts; the results are better than those reported for ruthenium-complex mediated photoarylations. Additionally, we demonstrate the robustness of this methodology with a 5 mmol scaled-up experiment. Mechanistic studies were carried out giving support to the proposal of a photocatalyzed approach by an electron donor-acceptor (EDA) complex, also highlighting the crucial role that solvents play in the formation of the EDA complex. This journal is
Synthesis of Chemically and Configurationally Stable Monofluoro Acylboronates: Effect of Ligand Structure on their Formation, Properties, and Reactivities
Noda, Hidetoshi,Bode, Jeffrey W.
supporting information, p. 3958 - 3966 (2015/04/14)
The recent disclosures of two classes of acylborons, potassium acyltrifluoroborates (KATs) and N-methyliminodiacetyl (MIDA) acylboronates, demonstrated that certain acylboron species can be both remarkably stable and uniquely reactive. Here we report new classes of ligands for acylboronates that have a significant influence on the formation, properties, and reactivities of acylboronates. Our systematic investigations identified a class of neutral, monofluoroboronates that can be prepared in a one step, gram-scale fashion from readily accessible KATs. These monofluoroboronates are stable to air, moisture, and silica gel chromatography and can be easily handled without any special precautions. X-ray crystallography, NMR spectroscopy, and HPLC studies showed that they are tetravalent, configurationally stable B-chiral acylboronates. Significantly, the ligands on the boronate allow for fine-tuning of the properties and reactivity of acylboronates. In amide-forming ligation with hydroxylamines under aqueous conditions, a considerable difference in reactivity was observed as a function of ligand structure. The solid-state structures suggested that subtle steric and conformational factors modulate the reactivities of the acylboronates.
Can Palladium Acetate Lose Its "saltiness"? Catalytic Activities of the Impurities in Palladium Acetate
Carole, William A.,Bradley, Jonathan,Sarwar, Misbah,Colacot, Thomas J.
supporting information, p. 5472 - 5475 (2015/11/18)
Commercially available palladium acetate often contains two major impurities, whose presence can impact the overall catalytic efficacy. This systematic study provides a comparison of the differences in catalytic activity of pure palladium acetate, Pd3(OAc)6, with the two impurities: Pd3(OAc)5(NO2) and polymeric [Pd(OAc)2]n in a variety of cross-coupling reactions. The solid state 13C NMR spectra of all three compounds in conjunction with DFT calculations confirm their reported geometries.
