Reactivity of Carbamoyl Radicals. A New, General, Convenient Free-Radical Synthesis of Isocyanates from Monoamides of Oxalic Acid
摘要:
A new, general, simple synthesis of isocyanates was developed by oxidation of monoamides of oxalic acid with peroxydisulfate catalyzed by Ag and Cu salts. The reaction was carried out in a two-phase system (water and an organic solvent), and it is suitable also for practical applications, due to the simple experimental conditions and the inexpensive as well as nontoxic reagents. The first example of homolytic intramolecular aromatic carbamoylation is also reported.
We have developed a high-efficiency and practical Cu-catalyzed cross-coupling to directly construct versatile α-aryl-esters by utilizing readily available aryl bromides (or chlorides) and malonates. These gram-scale approaches occur with turnovers of up to 1560 and are smoothly conducted by the usage of a low catalyst loading, a new available ligand, and a green solvent. A variety of functional groups
Oxalohydrazide Ligands for Copper‐Catalyzed C−O Coupling Reactions with High Turnover Numbers
作者:Ritwika Ray、John F. Hartwig
DOI:10.1002/anie.202015654
日期:2021.4.6
long‐lived copper catalysts for couplings that form the C−O bonds in biaryl ethers. These Cu‐catalyzed coupling of phenols with aryl bromides occurred with turnovers up to 8000, a value which is nearly two orders of magnitude higher than those of prior couplings to form biaryl ethers and nearly an order of magnitude higher than those of any prior copper‐catalyzed coupling of aryl bromides and chlorides
Asymmetric Transfer Hydrogenation of α-Keto Amides; Highly Enantioselective Formation of Malic Acid Diamides and α-Hydroxyamides
作者:Shweta K. Gediya、Vijyesh K. Vyas、Guy J. Clarkson、Martin Wills
DOI:10.1021/acs.orglett.1c02830
日期:2021.10.15
The asymmetric transfer hydrogenation (ATH) of α-keto-1,4-diamides using a tethered Ru/TsDPEN catalyst was achieved in high ee. Studies on derivatives identified the structural elements which lead to the highest enantioselectivities in the products. The α-keto-amide reduction products have been converted to a range of synthetically valuable derivatives.
使用系留的 Ru/TsDPEN 催化剂在高 ee 下实现了 α-酮基-1,4-二酰胺的不对称转移氢化(ATH)。对衍生物的研究确定了导致产品中最高对映选择性的结构元素。α-酮酰胺还原产物已转化为一系列具有合成价值的衍生物。
Reagent Design and Ligand Evolution for the Development of a Mild Copper-Catalyzed Hydroxylation Reaction
作者:Patrick S. Fier、Kevin M. Maloney
DOI:10.1021/acs.orglett.7b01403
日期:2017.6.2
modular ligand library, high-throughput experimentation, and rational ligand evolution have led to a novel copper catalyst for the synthesis of phenols with a traceless hydroxide surrogate. The mild reaction conditions reported here enable the late-stage synthesis of numerous complex, druglike phenols.
Cu/Oxalic Diamide-Catalyzed Coupling of Terminal Alkynes with Aryl Halides
作者:Ying Chen、Sailuo Li、Lanting Xu、Dawei Ma
DOI:10.1021/acs.joc.2c02882
日期:2023.3.3
6-Dimethylphenyl)-N2-(pyridin-2-ylmethyl)oxalamide (DMPPO) was revealed to be a more effective ligand for copper-catalyzedcouplingreaction of (hetero)aryl halides with 1-alkynes than previously reported ones. Only 3 mol % CuCl and DMPPO are required to make the coupling complete at 100 °C (for bromides) and 80 °C (for iodides). Both (hetero)aryl and alkyl substituted 1-alkynes worked well under these conditions
N 1 -(2,6-二甲基苯基)- N 2 -(吡啶-2-基甲基)草酰胺 (DMPPO) 被发现是铜催化的(杂)芳基卤化物与 1-炔烃偶联反应的更有效配体以前报道过的。仅需 3 mol% CuCl 和 DMPPO 即可在 100 °C(溴化物)和 80 °C(碘化物)下完成偶联。(杂)芳基和烷基取代的 1-炔烃在这些条件下都表现良好,导致内部炔烃的形成具有很大的多样性。