632326-58-0Relevant academic research and scientific papers
Reductive amidation of alkyl tosylates with isocyanates by a Ni/Co-dual catalytic system
Michiyuki, Takuya,Osaka, Itaru,Komeyama, Kimihiro
, p. 1247 - 1250 (2020)
Reductive amidation of alkyl tosylates with isocyanates using the Ni/Co-dual catalytic system is disclosed. The method proceeds efficiently under mild conditions, giving rise to the corresponding alkyl amides. Notably, the protocol can discriminate the steric environment of two alkyl tosylate moieties, enabling regioselective mono-amidation at the less-bulky site.
Low-Valent Tungsten Catalysis Enables Site-Selective Isomerization-Hydroboration of Unactivated Alkenes
Cooper, Phillippa,Engle, Keary M.,Jankins, Tanner C.,Martin, Ruben,Martin-Montero, Raul
supporting information, p. 14981 - 14986 (2021/09/29)
A tungsten-catalyzed hydroboration of unactivated alkenes at distal C(sp3)-H bonds aided by native directing groups is described herein. The method is characterized by its simplicity, exquisite regio- and chemoselectivity, and wide substrate scope, offering a complementary site-selectivity pattern to other metal-catalyzed borylation reactions and chain-walking protocols.
Anti-Markovnikov Hydroazidation of Alkenes by Visible-Light Photoredox Catalysis
Wang, Juan-Juan,Yu, Wei
supporting information, p. 3510 - 3514 (2019/02/19)
The anti-Markovnikov hydroazidation of alkenes has been accomplished under visible-light irradiation by using [Ir(dF(CF3)ppy)2(dtbbpy)]PF6 as the photocatalyst and trimethylsilyl azide as the azidating agent. The reactions were greatly facilitated by water, the beneficial effect of which can be attributed to its participation in the reaction as the hydrogen donor, as indicated by deuterium isotope experiments. The reactions proceed under solvent free conditions in the presence of water. 4-Dimethylaminopyridine also exhibited a beneficial effect on the reactions. The present method enabled hydroazidation of several types of unactivated alkenes with good yields and high regioselectivity.
Merging Photoredox PCET with Ni-Catalyzed Cross-Coupling: Cascade Amidoarylation of Unactivated Olefins
Zheng, Shuai,Gutiérrez-Bonet, álvaro,Molander, Gary A.
supporting information, p. 339 - 352 (2019/02/14)
The integration of amidyl radicals with cross-coupling chemistry opens new avenues for reaction design. However, the lack of efficient methods for the generation of such radical species has prevented many such transformations from being brought to fruition. Herein, the amidoarylation of unactivated olefins by a cascade process from non-functionalized amides is reported by merging, for the first time, photoredox proton-coupled electron transfer (PCET) with nickel catalysis. This new technology grants access to an array of complex molecules containing a privileged pyrrolidinone core from alkenyl amides and aryl- and heteroaryl halides in the presence of a visible light photocatalyst and a nickel catalyst. Notably, the reaction is not restricted to amides—carbamates and ureas can also be used. Mechanistic studies, including hydrogen-bond affinity constants, cyclization rate measurements, quenching studies, and cyclic voltammetry, were central to comprehend the subtleties contributing to the integration of the two catalytic cycles. A rapid, highly diastereoselective amidoarylation of unactivated olefins was achieved to render medicinally privileged pyrrolidinone structures. Taking advantage of a photoredox proton-coupled electron transfer process, amidyl radicals were obtained from non-prefunctionalized N–H bonds under mild conditions, which were subsequently trapped by pendant olefins, delivering alkyl radicals for nickel-catalyzed cross-coupling. Mechanistic studies revealed the key balance between thermodynamically-driven radical generation and kinetically-driven cyclization, which led to expanding the scope toward urea and carbamate substrates. Rapid generation of molecular complexity and access to novel 3D chemical space is pivotal for successful and efficient drug discovery. Nickel/photoredox dual catalysis has arisen as an appealing strategy toward such a goal by rapidly introducing Csp3 centers under mild reaction conditions. By taking advantage of a native amide group, we achieved an amidoarylation reaction of unactivated olefins, rendering a series of medicinally privileged structures in a highly atom-economical way. The reaction takes advantage of a photoredox proton-coupled electron transfer event to cleave the strong amidyl N–H bond homolytically. Subsequent regiospecific 5-exo-trig cyclization generates an alkyl radical. High functional group tolerance was achieved with excellent diastereoselectivities owing to the reaction's mild nature. Mechanistic studies showed the intricate relationship between the base stoichiometry and the N–H donor, as well as the key balance between kinetic and thermodynamic factors.
Br?nsted Base Assisted Photoredox Catalysis: Proton Coupled Electron Transfer for Remote C?C Bond Formation via Amidyl Radicals
Jia, Jiaqi,Ho, Yee Ann,Bülow, Raoul F.,Rueping, Magnus
supporting information, p. 14054 - 14058 (2018/09/14)
The synthesis of alkyne- and alkene-decorated lactams has been achieved through a photoredox-initiated radical cascade reaction. The developed Br?nsted base assisted, photoredox-catalyzed, intramolecular 5-exo-trig cyclization/intermolecular radical addit
Synthesis of Substituted γ- and δ-Lactams via Pd-Catalyzed Alkene Carboamination Reactions
Boothe, Jordan R.,Shen, Yifan,Wolfe, John P.
, p. 2777 - 2786 (2017/03/14)
The synthesis of substituted γ- and δ-lactams via palladium-catalyzed alkene carboamination reactions between aryl halides and alkenes bearing pendant amides is described. The substrates for these reactions are generated in 1-3 steps from commercially ava
Pd(0)-catalyzed alkene oxy- and aminoalkynylation with aliphatic bromoacetylenes
Nicolai, Stefano,Sedigh-Zadeh, Raha,Waser, Jeroime
, p. 3783 - 3801 (2013/06/26)
Tetrahydrofurans and pyrrolidines are among the most important heterocycles found in bioactive compounds. Cyclization-functionalization domino reactions of alcohols or amines onto olefins constitute one of the most efficient methods to access them. In this context, oxy- and aminoalkynylation are especially important reactions, because of the numerous transformations possible with the triple bond of acetylenes, yet these methods have been limited to the use of silyl protected acetylenes. Herein, we report the first palladium-catalyzed oxy- and aminoalkynylation using aliphatic bromoalkynes, which proceeded with high diastereoselectivity and functional group tolerance. A one-pot hydrogenation of the triple bond gave then access to alkyl-substituted tetrahydrofurans and pyrroldines. Finally, a detailed study of the side products formed during the reaction gave a first insight into the reaction mechanism.
Study on the total synthesis of velbanamine: Chemoselective dioxygenation of alkenes with PIFA via a stop-and-flow strategy
Liu, Huili,Zheng, Kuan,Lu, Xiang,Wang, Xiaoxia,Hong, Ran
supporting information, p. 983 - 990 (2013/07/19)
A "stop-and-flow" strategy was developed for the chemoselective dioxygenation of alkenes with a PIFA-initiated cyclization. This method is conceived for the desymmetrization of seco-diene, and a series of substituted 5-hydroxymethyl-γ-lactones were constructed after hydrolysis. This strategy also differentiates terminally substituted alkenes and constitutes a potentially novel synthetic approach for the efficient synthesis toward velbanamine.
Silver-catalyzed radical aminofluorination of unactivated alkenes in aqueous media
Li, Zhaodong,Song, Liyan,Li, Chaozhong
supporting information, p. 4640 - 4643 (2013/05/09)
We report herein a mild and catalytic intramolecular aminofluorination of unactivated alkenes. Thus, with the catalysis of AgNO3, the reactions of various N-arylpent-4-enamides with Selectfluor reagent in CH 2Cl2/H2/
On the phenyliodine(III)-bis(trifluoroacetate)-mediated olefin amidohydroxylation reaction
Tellitu, Imanol,Urrejola, Andrea,Serna, Sonia,Moreno, Isabel,Herrero, M. Teresa,Dominguez, Esther,SanMartin, Raul,Correa, Arkaitz
, p. 437 - 444 (2008/02/03)
When appropriately substituted amides are treated with PIFA in a non-nudeophilic solvent like trifluoroethanol, a stable N-acylnitrenium ion is generated. If under such conditions a C=C double bond is present in the molecule, an intramolecular cyclization
