Palladium-Catalyzed Alkoxycarbonylation of sec-Benzylic Ethers

Herein, we report the palladium-catalyzed synthesis of 3-arylpropionate esters starting from secondary benzylic ethers. With this investigation it could be shown that ethers are suitable starting materials in addition to the established carbonylation reactions of olefins, alcohols, or aryl halides. © 2020 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA

肺結核と梶井基次郎の文学

千葉大学大学院人文社会科学研究科研究プロジェクト報告書第184集『日本近代文学と病』 滝藤満義

Base Metal Catalyzed Isocyanide Insertions

Isocyanides are diverse C1 building blocks considering their potential to react with nucleophiles, electrophiles, and radicals. Therefore, perhaps not surprisingly, isocyanides are highly valuable as inputs for multicomponent reactions (MCRs) and other one-pot cascade processes. In the field of organometallic chemistry, isocyanides typically serve as ligands for transition metals. The coordination of isocyanides to metal centers alters the electronic distribution of the isocyano moiety, and reaction pathways can therefore be accessed that are not possible in the absence of the metal. The tunable reactivity of the isocyanide functional group by transition metals has evolved into numerous useful applications. Especially palladium-catalyzed isocyanide insertion processes have emerged as powerful reactions in the past decade. However, reports on the use of earth-abundant and cheap base metals in these types of transformations are scarce and have received far less attention. In this Minireview, we focus on these emerging base metal catalyzed reactions and highlight their potential in synthetic organic chemistry. Although mechanistic studies are still scarce, we discuss distinct proposed catalytic cycles and categorize the literature according to 1) the (hetero)atom bound to and 2) the type of bonding with the transition metal in which the (formal) insertion occurs

Palladium-Catalyzed Construction of Amidines from Arylboronic Acids under Oxidative Conditions

A valuable palladium-catalyzed three-component coupling reaction for the synthesis of amidines has been developed. Using arylboronic acids, isocyanides, and anilines as the reactants under oxidative conditions, various amidines were isolated in good yields with good functional group tolerances

Modular Three-Component Synthesis of 4‑Aminoquinolines via an Imidoylative Sonogashira/Cyclization Cascade

We developed a one-pot, two-stage synthetic route to substituted 4-aminoquinolines involving an imidoylative Sonogashira coupling followed by acid-mediated cyclization. This three-component reaction affords pharmaceutically valuable 4-aminoquinolines in a one-pot procedure from readily available starting materials. The reaction tolerates various substituents on the arene as well as the use of secondary and even primary isocyanides. Additionally, the wide tolerance for functionalized isocyanides allows for the one-pot synthesis of various substituted chloroquine analogues as well as other medicinally relevant products

Synthesis of Quinazolin-4-ones by Copper-Catalyzed Isocyanide Insertion

Herein, we report a novel copper-catalyzed imidoylative cross-coupling/cyclocondensation reaction between 2-isocyanobenzoates and amines efficiently producing quinazolin-4-ones. The reaction utilizes Cu(II) acetate as an environmentally benign catalyst in combination with a mild base and proceeds well in anisole, a recommended, sustainable solvent. Additionally, the reaction does not require dry conditions or inert atmospheres for optimal performance. The scope of this isocyanide insertion reaction is rather broad, tolerating various functionalized isocyanobenzoates and a range of substituted amines, although the use of aromatic amines as nucleophiles requires microwave heating

Oxidative Addition of Haloheteroarenes to Palladium(0): Concerted versus S N Ar-Type Mechanism

International audienceThe kinetics of the oxidative additions of haloheteroarenes HetX (X=I, Br, Cl) to [Pd-0(PPh3)(2)] (generated from [Pd-0(PPh3)(4)]) have been investigated in THF and DMF and the rate constants have been determined. In contrast to the generally accepted concerted mechanism, Hammett plots obtained for substituted 2-halopyridines and solvent effects reveal a reaction mechanism dependent on the halide X of HetX: an unprecedented SNAr-type mechanism for X=Br or Cl and a classical concerted mechanism for X=I. These results are supported by DFT studies

Synthesis of Densely Functionalized Pyrimidouracils by Nickel(II)-Catalyzed Isocyanide Insertion

A robust nickel-catalyzed oxidative isocyanide insertion/C-H amination by reaction of readily available N-uracil-amidines with isocyanides affording polysubstituted pyrimidouracils has been reported. The reaction proceeds in moderate to quantitative yield, under mild conditions (i.e., green solvent, air atmosphere, moderate temperature). The broad range of structurally diverse isocyanides and N-uracil-amidines that are tolerated make this method an interesting alternative to the currently available procedures toward pyrimidouracils