- A practical modification of the Barton-McCombie reaction and radical O- to S- rearrangement of xanthates
-
The C-O bond in xanthates derived from carbohydrates can be reductively cleaved by heating in 2-propanol in the presence of equimolar amounts of dilauroyl peroxide, added in small portions; if benzene is used as the solvent, an O- to S- rearrangement of the xanthate occurs.
- Quiclet-Sire, Beatrice,Zard, Samir Z.
-
-
Read Online
- Microwave assisted, palladium catalyzed aminocarbonylations of heteroaromatic bromides using solid Mo(CO)6 as the carbon monoxide source
-
The direct conversion of a variety of heteroaromatic bromides into heteroaromatic amides is described. This reaction utilizes Mo(CO)6 as the carbon monoxide source and is performed using microwave heating allowing for very short reaction times. This convenient methodology allows for the preparation of a variety of heteroaromatic amides useful in medicinal chemistry applications.
- Letavic, Michael A.,Ly, Kiev S.
-
-
Read Online
- TBAI-catalyzed C–N bond formation through oxidative coupling of benzyl bromides with amines: a new avenue to the synthesis of amides
-
A new green approach for the synthesis of amide through TBAI-catalyzed oxidative coupling of benzyl bromides with amine was developed in the presence of tert-butyl hydroperoxide (TBHP) as an oxidant. Various electron-donating and withdrawing groups containing benzyl bromides and various amines, were subjected to the reaction and transformed to the corresponding amide in good to excellent yields.
- Kumar, Dhirendra,Maury, Suresh Kumar,Kumari, Savita,Kamal, Arsala,Singh, Himanshu Kumar,Singh, Sundaram,Srivastava, Vandana
-
supporting information
p. 424 - 432
(2022/02/09)
-
- Iron-catalyzed oxidative amidation of acylhydrazines with amines
-
A new approach for amide bond formation via a mild and efficient Iron-catalyzed cross-coupling reaction of acylhydrazines and amines using TBHP as oxidant is described. This protocol is compatible with a wide range of amines and acylhydrazines. In addition, the synthetic application of the reaction is presented.
- Wang, Yi-Jie,Zhang, Guo-Yu,Shoberu, Adedamola,Zou, Jian-Ping
-
supporting information
(2021/08/18)
-
- Photocatalytic aldehydes/alcohols/toluenes oxidative amidation over bifunctional Pd/MOFs: Effect of Fe-O clusters and Lewis acid sites
-
Heterogeneous photocatalytic organic synthesis is fascinating because of the utilization of ubiquitous solar light for chemical transformations. Here, three Fe-MOFs with different Fe-O clusters, Lewis acid sites and morphologies were synthesized through coordination structure engineering. Pd/Fe-MOFs nanocomposites were used to challenge the amide bond green synthesis with visible light. Pd/MIL-101(Fe) exhibited the best photocatalytic performance due to the easily excited Fe3-μ3-oxo clusters for light absorption, the efficient photogenerated carriers separation and migration, the large amount of Lewis acid sites based aldehydes and amines condensation promotion and the efficient O2 reduction to superoxide radicals over photogenerated electron-rich Pd NPs. Various aldehydes, alcohols and toluenes could be transformed to amide compounds with amines over Pd/MIL-101(Fe) with just oxygen or air as the green oxidant and water as the by-product. One-pot C–C cross-coupling and photo-redox C–N coupling cascade reactions could also be achieved over Pd/MIL-101(Fe). This work shed light on the efficient and sustainable amide bonds synthesis.
- Bian, Fengxia,Cheng, Hongmei,Jiang, Heyan,Sun, Bin,Tan, Jiangwei,Zang, Cuicui
-
p. 279 - 287
(2021/08/21)
-
- Catalytic N-Acylation of Cyclic Amines by Arylglyoxylic Acids via Radical-Radical Cross-Coupling
-
A methodical mechanistic investigation allowed for the catalytic N-acylation of secondary cyclic amine counterparts by arylglyoxylic acids through radical-radical coupling. The reaction proceeds via a twofold SET-promoted Cu(I)/Cu(II) catalytic cycle under mild conditions. An analogous reaction variant allows for the N-acylation in a one-pot fashion directly starting from a secondary cyclic amine even in the presence of a second amine or hydroxy group.
- Bhadra, Sukalyan,Gupta, Aniket,Kumar Singh, Anupam,Rahaman, Ajijur
-
p. 2198 - 2202
(2021/07/22)
-
- Remarkably Efficient Iridium Catalysts for Directed C(sp2)-H and C(sp3)-H Borylation of Diverse Classes of Substrates
-
Here we describe the discovery of a new class of C-H borylation catalysts and their use for regioselective C-H borylation of aromatic, heteroaromatic, and aliphatic systems. The new catalysts have Ir-C(thienyl) or Ir-C(furyl) anionic ligands instead of the diamine-type neutral chelating ligands used in the standard C-H borylation conditions. It is reported that the employment of these newly discovered catalysts show excellent reactivity and ortho-selectivity for diverse classes of aromatic substrates with high isolated yields. Moreover, the catalysts proved to be efficient for a wide number of aliphatic substrates for selective C(sp3)-H bond borylations. Heterocyclic molecules are selectively borylated using the inherently elevated reactivity of the C-H bonds. A number of late-stage C-H functionalization have been described using the same catalysts. Furthermore, we show that one of the catalysts could be used even in open air for the C(sp2)-H and C(sp3)-H borylations enabling the method more general. Preliminary mechanistic studies suggest that the active catalytic intermediate is the Ir(bis)boryl complex, and the attached ligand acts as bidentate ligand. Collectively, this study underlines the discovery of new class of C-H borylation catalysts that should find wide application in the context of C-H functionalization chemistry.
- Chattopadhyay, Buddhadeb,Hassan, Mirja Md Mahamudul,Hoque, Md Emdadul
-
p. 5022 - 5037
(2021/05/04)
-
- Metal-Free Selective Modification of Secondary Amides: Application in Late-Stage Diversification of Peptides
-
Here we solve a long-standing challenge of the site-selective modification of secondary amides and present a simple two-step, metal-free approach to selectively modify a particular secondary amide in molecules containing multiple primary and secondary amides. Density functional theory (DFT) provides insight into the activation of C-N bonds. This study encompasses distinct chemical advances for late-stage modification of peptides thus harnessing the amides for the incorporation of various functional groups into natural and synthetic molecules.
- Adebomi, Victor,Sriram, Mahesh,Streety, Xavier,Raj, Monika
-
p. 6189 - 6193
(2021/08/01)
-
- Fluorinated solvent-assisted photocatalytic aerobic oxidative amidation of alcoholsviavisible-light-mediated HKUST-1/Cs-POMoW catalysis
-
Considering the irreplaceable importance of photocatalytic functionalization reactions and the widespread attention paid to the use of metal-organic frameworks, especially their modified variants, for this purpose in recent years, different types of HKUST-1/POMoW composites were prepared through the immobilization of a series of Keggin-type polyoxometalates (POMs; POW = H3PW12O40, POMo = H3PMo12O40, and POMoW = H3PMo6W6O40) on HKUST-1 as a metal-organic framework (HKUST-1; Cu3(1,3,5-benzenetricarboxilicacid)2). Then, to produce HKUST-1/Cs-POM, the substitution of H+cations with Cs+ones as counter cations was carried out. The prepared composites were fully characterized with the PXRD (powder X-ray diffraction), FT-IR (Fourier transform infrared spectroscopy), BET and BJH (sorption of N2), TGA (thermo-gravimetric analysis), SEM (scanning electron microscopy), EDX (energy dispersive X-ray), TEM (transmission electron microscopy), UV-vis DRS (diffuse reflectance UV-vis spectroscopy), photoluminescence (PL) spectroscopy and ICP-AES (inductively coupled plasma atomic emission spectroscopy) techniques. The great importance?of the amide functional group and the attractiveness of photocatalytic oxidative functionalization?reactions led us to study the formation of this functional group using the prepared catalytic system in line with our previous research in this field. The HKUST-1/Cs-POMoW composite showed a raised photocatalytic performance compared to the discrete components, HKUST-1 and Cs-POMs, in aerobic oxidative amidation of alcohols under illumination with visible light, owing to the presence of catalytically active Cs-POMs deposited on the MOF particles. Besides, the combination of composite components mitigated the recombination rate of the electron-hole pairs, raising its photocatalytic activity. The attractiveness of fluorine solvents for oxidation reactions has led to the study of their role in the efficiency of oxidative amidation of alcohols and their significant effect on the efficiency of the process has been confirmed. The Cu-MOF/POM catalyst showed excellent stability during the reaction, and no significant decrease in its ability was observed during five consecutive cycles.
- Azarkhosh, Zahra,Heydari, Akbar,Karimi, Meghdad,Mahjoub, Alireza,Mohebali, Haleh,Sadeghi, Samira,Safarifard, Vahid
-
supporting information
p. 14024 - 14035
(2021/08/16)
-
- Pd-Catalyst Containing a Hemilabile P,C-Hybrid Ligand in Amino Dicarbonylation of Aryl Halides for Synthesis of α-Ketoamides
-
The amino dicarbonylation of aryl halides affording α-ketoamides with Pd catalysts is highly dependent on the stereoelectronic properties of the involved ligands. Ionic diphosphine ligand L4 can serve as precursor of a hemilabile P,C (phosphine, carbene)-hybrid ligand to form a stable Pd(II)-complex, Pd-L4. In contrast, analogues L1-L3 with a similar 1-(thiophen-3-yl)-benzimidazolyl skeleton behave as typical (mono/di)phosphines. The catalytic system resulting from the complexation of PdCl2(MeCN)2 and L4 exhibits good catalytic performance in terms of aryl iodides conversion (81-95%) and α-ketoamide selectivity (80-91%), as well as the available recyclability in the RTIL of [Bpy]BF4. The in situ FT-IR analysis reveals that the PdCl2(MeCN)2-L4 catalytic system favors the amino dicarbonylation toward α-ketoamides according to the proposed mechanism of cycle I, which involves two independent CO-insertion steps.
- Yang, Shu-Qing,Yao, Yin-Qing,Chen, Xiao-Chao,Lu, Yong,Zhao, Xiao-Li,Liu, Ye
-
p. 1032 - 1041
(2021/05/07)
-
- Deoxygenative hydroboration of primary, secondary, and tertiary amides: Catalyst-free synthesis of various substituted amines
-
Transformation of relatively less reactive functional groups under catalyst-free conditions is an interesting aspect and requires a typical protocol. Herein, we report the synthesis of various primary, secondary, and tertiary amines through hydroboration of amides using pinacolborane under catalyst-free and solvent-free conditions. The deoxygenative hydroboration of primary and secondary amides proceeded with excellent conversions. The comparatively less reactive tertiary amides were also converted to the corresponding N,N-diamines in moderate yields under catalyst-free conditions, although alcohols were obtained as a minor product.
- An, Duk Keun,Jaladi, Ashok Kumar,Kim, Hyun Tae,Yi, Jaeeun
-
supporting information
(2021/11/17)
-
- A practical and sustainable protocol for direct amidation of unactivated esters under transition-metal-free and solvent-free conditions
-
In this paper, a NaOtBu-mediated synthesis approach was developed for direct amidation of unactivated esters with amines under transition-metal-free and solvent-free conditions, affording a series of amides in good to excellent yields at room temperature. In particular, an environmentally friendly and practical workup procedure, which circumvents the use of organic solvents and chromatography in most cases, was disclosed. Moreover, the gram-scale production of representative products3a,3wand3auwas efficiently realized by applying operationally simple, sustainable and practical procedures. Furthermore, this approach was also applicable to the synthesis of valuable molecules such as moclobemide (a powerful antidepressant), benodanil and fenfuram (two commercial agricultural fungicides). These results demonstrate that this protocol has the potential to streamline amide synthesis in industry. Meanwhile, quantitative green metrics of all the target products were evaluated, implying that the present protocol is advantageous over the reported ones in terms of environmental friendliness and sustainability. Finally, additional experiments and computational calculations were carried out to elucidate the mechanistic insight of this transformation, and one plausible mechanism was provided on the basis of these results and the related literature reports.
- Chen, Cheng,Cheng, Hua,Du, Min-Chen,Qian, Liang,Qin, Xin,Sang, Wei,Yao, Wei-Zhong,Yuan, Ye,Zhang, Rui
-
supporting information
p. 3972 - 3982
(2021/06/17)
-
- Method for preparing amide from carboxylic acid under irradiation of blue light by taking iridium and cobalt complexes as catalysts
-
The invention relates to a method for preparing amide from carboxylic acid under the irradiation of blue light by taking iridium and cobalt complexes as catalysts, and belongs to the field of chemistry. The method comprises the following step of: by taking R substituted carboxylic acid and R1' and R2' substituted amines as raw materials, triphenylphosphine as a deoxidizing agent, [Ir(dF(CF3)ppy)2(dtbbpy)]PF6 as a photocatalyst and Co(dmgH)(dmgH2)Cl2 as a metal complex catalyst, reacting in dichloromethane in an inert atmosphere and under the irradiation of blue light to obtain an amide compound, wherein R is an aryl group, a heteroaryl group, a protected amino group, a substituted alkyl group, a substituted aryl group or a substituted protected amino group, R1' is a hydrogen group, a substituted alkyl group, a phenyl group or a substituted phenyl group, and R2' is a hydrogen group, a substituted alkyl group, a phenyl group or a substituted phenyl group.
- -
-
Paragraph 0089-0090
(2021/05/12)
-
- Ammonia-borane as a Catalyst for the Direct Amidation of Carboxylic Acids
-
Ammonia-borane serves as an efficient substoichiometric (10%) precatalyst for the direct amidation of both aromatic and aliphatic carboxylic acids. In situ generation of amine-boranes precedes the amidation and, unlike the amidation with stoichiometric amine-boranes, this process is facile with 1 equiv of the acid. This methodology has high functional group tolerance and chromatography-free purification but is not amenable for esterification. The latter feature has been exploited to prepare hydroxyl- and thiol-containing amides.
- Ramachandran, P. Veeraraghavan,Hamann, Henry J.
-
supporting information
p. 2938 - 2942
(2021/05/04)
-
- A Fast and General Route to Ketones from Amides and Organolithium Compounds under Aerobic Conditions: Synthetic and Mechanistic Aspects
-
We report that the nucleophilic acyl substitution reaction of aliphatic and (hetero)aromatic amides by organolithium reagents proceeds quickly (20 s reaction time), efficiently, and chemoselectively with a broad substrate scope in the environmentally responsible cyclopentyl methyl ether, at ambient temperature and under air, to provide ketones in up to 93 % yield with an effective suppression of the notorious over-addition reaction. Detailed DFT calculations and NMR investigations support the experimental results. The described methodology was proven to be amenable to scale-up and recyclability protocols. Contrasting classical procedures carried out under inert atmospheres, this work lays the foundation for a profound paradigm shift of the reactivity of carboxylic acid amides with organolithiums, with ketones being straightforwardly obtained by simply combining the reagents under aerobic conditions and with no need of using previously modified or pre-activated amides, as recommended.
- Ghinato, Simone,Territo, Davide,Maranzana, Andrea,Capriati, Vito,Blangetti, Marco,Prandi, Cristina
-
supporting information
p. 2868 - 2874
(2021/01/21)
-
- Direct Synthesis of Enamides via Electrophilic Activation of Amides
-
A novel, one-step N-dehydrogenation of amides to enamides is reported. This reaction employs the unlikely combination of LiHMDS and triflic anhydride, which serves as both the electrophilic activator and the oxidant, and is characterized by its simple setup and broad substrate scope. The synthetic utility of the formed enamides was readily demonstrated in a range of downstream transformations.
- Berger, Martin,Kaiser, Daniel,Maulide, Nuno,Spie?, Philipp
-
supporting information
p. 10524 - 10529
(2021/07/28)
-
- Heteroaliphatic Dimethylphosphine Oxide Building Blocks: Synthesis and Physico-Chemical Properties
-
Scalable synthesis of saturated heterocyclic dimethyl phosphine oxides (derivatives of azetidine, pyrrolidine, piperidine, and morpholine) is disclosed. The key steps of the synthesis relied on the reactions of HP(O)Me2, i. e. the phospha-Mannich (the Kabachnik-Fields-type) condensation with cyclic imines or monoprotected diamines, palladium-catalyzed reactions of alkenyl halides or trifltates (generated from cyclic ketones), as well as base-mediated nucleophilic substitution, Michael addition, or oxirane ring opening. It was shown that introducing the P(O)Me2 group into the saturated heterocyclic core had very strong impact on the compound's basicity: the corresponding α-, β-, and γ-isomeric derivatives were by ca. 4, 2, and 1.6 pKa units less basic, respectively, as compared to the parent saturated heterocycle. Meanwhile, the P(O)Me2-substituted compound was more basic than its SO2i-Pr and SO2NMe2-containing isosteres (by ca. 1.2 and 0.4 pKa units, respectively). It was also demonstrated that the P(O)Me2 group typically increased the compound's hydrophilicity and aqueous solubility. In particular, the LogP values for the corresponding derivatives were by ca. 1.4–1.7 and 0.6 units lower than for the non-substituted counterpart and sulfonamide/sulfone isosteres, respectively. Finally, a potential of the synthesized building blocks to generate lead-like three-dimensional compound libraries was confirmed using the Nelson's LLAMA tool.
- Fedyk, Andrii,Slobodyanyuk, Evgeniy Y.,Stotska, Olha,Vashchenko, Bohdan V.,Volochnyuk, Dmitriy M.,Sibgatulin, Dmitriy A.,Tolmachev, Andrey A.,Grygorenko, Oleksandr O.
-
p. 6591 - 6603
(2021/06/16)
-
- Hydrosilylative reduction of primary amides to primary amines catalyzed by a terminal [Ni-OH] complex
-
A terminal [Ni-OH] complex1, supported by triflamide-functionalized NHC ligands, catalyzes the hydrosilylative reduction of a range of primary amides into primary amines in good to excellent yields under base-free conditions with key functional group tolerance. Catalyst1is also effective for the reduction of a variety of tertiary and secondary amides. In contrast to literature reports, the reactivity of1towards amide reduction follows an inverse trend,i.e., 1° amide > 3° amide > 2° amide. The reaction does not follow a usual dehydration pathway.
- Bera, Jitendra K.,Pandey, Pragati
-
supporting information
p. 9204 - 9207
(2021/09/20)
-
- Cobalt(iii)-catalyzed C-H amidation of: N, N -dialkyl thiobenzamides by sulfur coordination
-
An efficient inexpensive cobalt(iii)-catalyzed intermolecular amidation of N,N-dialkyl thiobenzamides with 1,4,2-dioxazol-5-ones via C-H bond activation is described. The reaction proceeds with high functional group tolerance under external oxidant free conditions, providing a straightforward approach for the direct modification of thioamide derivatives, which are prevalent organic motifs found in vital biological and pharmaceutical molecules. This journal is
- Gao, Pengpeng,Zhang, Xiaohui,Zheng, Qing-Zhong
-
supporting information
p. 10332 - 10336
(2021/12/17)
-
- Direct Amidation of Esters by Ball Milling**
-
The direct mechanochemical amidation of esters by ball milling is described. The operationally simple procedure requires an ester, an amine, and substoichiometric KOtBu and was used to prepare a large and diverse library of 78 amide structures with modest to excellent efficiency. Heteroaromatic and heterocyclic components are specifically shown to be amenable to this mechanochemical protocol. This direct synthesis platform has been applied to the synthesis of active pharmaceutical ingredients (APIs) and agrochemicals as well as the gram-scale synthesis of an active pharmaceutical, all in the absence of a reaction solvent.
- Barreteau, Fabien,Battilocchio, Claudio,Browne, Duncan L.,Godineau, Edouard,Leitch, Jamie A.,Nicholson, William I.,Payne, Riley,Priestley, Ian
-
supporting information
p. 21868 - 21874
(2021/09/02)
-
- Amide Bond Formation via Aerobic Photooxidative Coupling of Aldehydes with Amines Catalyzed by a Riboflavin Derivative
-
We report an effective, operationally simple, and environmentally friendly system for the synthesis of tertiary amides by the oxidative coupling of aromatic or aliphatic aldehydes with amines mediated by riboflavin tetraacetate (RFTA), an inexpensive organic photocatalyst, and visible light using oxygen as the sole oxidant. The method is based on the oxidative power of an excited flavin catalyst and the relatively low oxidation potential of the hemiaminal formed by amine to aldehyde addition.
- Hassan Tolba, Amal,Krupi?ka, Martin,Chudoba, Josef,Cibulka, Radek
-
supporting information
p. 6825 - 6830
(2021/09/11)
-
- One-Pot Synthesis of Tertiary Amides from Organic Trichlorides through Oxygen Atom Incorporation from Air by Convergent Paired Electrolysis
-
A convergent paired electrolysis catalyzed by a B12 complex for the one-pot synthesis of a tertiary amide from organic trichlorides (R-CCl3) has been developed. Various readily available organic trichlorides, such as benzotrichloride and its derivatives, chloroform, dichlorodiphenyltrichloroethane (DDT), trichloro-2,2,2-trifluoroethane (CFC-113a), and trichloroacetonitrile (CNCCl3), were converted to amides in the presence of tertiary amines through oxygen incorporation from air at room temperature. The amide formation mechanism in the paired electrolysis, which was mediated by a cobalt complex, was proposed.
- Luo, Zhongli,Imamura, Kenji,Shiota, Yoshihito,Yoshizawa, Kazunari,Hisaeda, Yoshio,Shimakoshi, Hisashi
-
p. 5983 - 5990
(2021/05/04)
-
- Practical one-pot amidation of N -Alloc-, N -Boc-, and N -Cbz protected amines under mild conditions
-
A facile one-pot synthesis of amides from N-Alloc-, N-Boc-, and N-Cbz-protected amines has been described. The reactions involve the use of isocyanate intermediates, which are generated in situ in the presence of 2-chloropyridine and trifluoromethanesulfonyl anhydride, to react with Grignard reagents to produce the corresponding amides. Using this reaction protocol, a variety of N-Alloc-, N-Boc-, and N-Cbz-protected aliphatic amines and aryl amines were efficiently converted to amides with high yields. This method is highly effective for the synthesis of amides and offers a promising approach for facile amidation.
- Hong, Wan Pyo,Tran, Van Hieu,Kim, Hee-Kwon
-
p. 15890 - 15895
(2021/05/19)
-
- Pd-Catalyzed Oxidative Aminocarbonylation of Arylboronic Acids with Unreactive Tertiary Amines via C-N Bond Activation
-
An efficient synthesis of tertiary amides from aryl boronic acids and inert tertiary amines through the oxidative carbonylation via C(sp3)-N bond activation is presented. This protocol significantly restricts the homocoupling biarylketone product. It involves the use of a homogeneous PdCl2/CuI catalyst and a heterogeneous Pd/C based catalyst, which promotes C(sp3)-N bond activation of tertiary amines with aryl boronic acids. This process represents a ligand-free, base-free, and recyclable catalyst along with an ideal oxidant like molecular oxygen.
- Kolekar, Yuvraj A.,Bhanage, Bhalchandra M.
-
p. 14028 - 14035
(2021/05/29)
-
- Two-step continuous flow synthesis of amide via oxidative amidation of methylarene
-
A green and efficient method for the synthesis of amides has been developed through oxidative amidation between methylarenes with amines in a two-step continuous flow system. This method integrates methylarene oxidation and amide formation into a single operation which is usually accomplished separately. Oxidation with tert-butyl hydroperoxide (TBHP) as “green” oxidant, the synthesis of amides under mild reaction conditions in continuous flow system and the utilization of methylarenes as starting material make this methodology novel and environment friendly. The practical value of this method is highlighted through the synthesis of high-profile pharmaceutical agents, acetylprocainamide.
- Fang, Zheng,Guo, Kai,He, Wei,Liu, Chengkou,Shi, Tingting,Yang, Yuhang,Yang, Zhao,Zhang, Zhimin
-
supporting information
(2020/02/28)
-
- Cobalt-catalyzed aminocarbonylation of (hetero)aryl halides promoted by visible light
-
The catalytic aminocarbonylation of (hetero)aryl halides is widely applied in the synthesis of amides but relies heavily on the use of precious metal catalysis. Herein, we report an aminocarbonylation of (hetero)aryl halides using a simple cobalt catalyst under visible light irradiation. The reaction extends to the use of (hetero)aryl chlorides and is successful with a broad range of amine nucleophiles. Mechanistic investigations are consistent with a reaction proceeding via intermolecular charge transfer involving a donor-acceptor complex of the substrate and cobaltate catalyst.
- Alexanian, Erik J.,Veatch, Alexander M.
-
p. 7210 - 7213
(2020/07/23)
-
- Tandem Photoredox Catalysis: Enabling Carbonylative Amidation of Aryl and Alkylhalides
-
We report a new visible-light-mediated carbonylative amidation of aryl, heteroaryl, and alkyl halides. A tandem catalytic cycle of [Ir(ppy)2(dtb-bpy)]+ generates a potent iridium photoreductant through a second catalytic cycle in the presence of DIPEA, which productively engages aryl bromides, iodides, and even chlorides as well as primary, secondary, and tertiary alkyl iodides. The versatile in situ generated catalyst is compatible with aliphatic and aromatic amines, shows high functional-group tolerance, and enables the late-stage amidation of complex natural products.
- Connell, Timothy U.,Forni, José A.,Micic, Nenad,Polyzos, Anastasios,Weragoda, Geethika
-
supporting information
p. 18646 - 18654
(2020/08/21)
-
- Ultrafast amidation of esters using lithium amides under aerobic ambient temperature conditions in sustainable solvents
-
Lithium amides constitute one of the most commonly used classes of reagents in synthetic chemistry. However, despite having many applications, their use is handicapped by the requirement of low temperatures, in order to control their reactivity, as well as the need for dry organic solvents and protective inert atmosphere protocols to prevent their fast decomposition. Advancing the development of air- and moisture-compatible polar organometallic chemistry, the chemoselective and ultrafast amidation of esters mediated by lithium amides is reported. Establishing a novel sustainable access to carboxamides, this has been accomplished via direct C-O bond cleavage of a range of esters using glycerol or 2-MeTHF as a solvent, in air. High yields and good selectivity are observed while operating at ambient temperature, without the need for transition-metal mediation, and the protocol extends to transamidation processes. Pre-coordination of the organic substrate to the reactive lithium amide as a key step in the amidation processes has been assessed, enabling the structural elucidation of the coordination adduct [{Li(NPh2)(OCPh(NMe2))}2] (8) when toluene is employed as a solvent. No evidence for formation of a complex of this type has been found when using donor THF as a solvent. Structural and spectroscopic insights into the constitution of selected lithium amides in 2-MeTHF are provided that support the involvement of small kinetically activated aggregates that can react rapidly with the organic substrates, favouring the C-O bond cleavage/C-N bond formation processes over competing hydrolysis/degradation of the lithium amides by moisture or air.
- Bole, Leonie J.,Fairley, Michael,García-Alvarez, Joaquín,Hevia, Eva,Kennedy, Alan R.,Main, Laura,Mulks, Florian F.,O'Hara, Charles T.
-
p. 6500 - 6509
(2020/07/15)
-
- Amine-boranes as Dual-Purpose Reagents for Direct Amidation of Carboxylic Acids
-
Amine-boranes serve as dual-purpose reagents for direct amidation, activating aliphatic and aromatic carboxylic acids and, subsequently, delivering amines to provide the corresponding amides in up to 99% yields. Delivery of gaseous or low-boiling amines as their borane complexes provides a major advantage over existing methodologies. Utilizing amine-boranes containing borane incompatible functionalities allows for the preparation of functionalized amides. An intermolecular mechanism proceeding through a triacyloxyborane-amine complex is proposed.
- Choudhary, Shivani,Hamann, Henry J.,Ramachandran, P. Veeraraghavan
-
-
- Well-defined N-heterocyclic carbene/ruthenium complexes for the alcohol amidation with amines: The dual role of cesium carbonate and improved activities applying an added ligand
-
Dehydrogenative amide bond formation from alcohols and amines has been regarded as an atom-economic and sustainable process. Among various catalytic systems, N-heterocyclic carbene (NHC)-based Ru catalytic systems have attracted growing interest due to the outstanding properties of NHCs as ligands. Herein, an NHC/Ru complex (1) was prepared and its structure was further confirmed with X-ray crystallography. In the presence of Cs2CO3, two NHC/Ru-based catalytic systems were disclosed to be active for this amide synthesis. System A, which did not contain any added ligand, required a catalyst loading of 1.00 mol%. Interestingly, improved catalytic performance was realized by the addition of an NHC precursor (L). Optimization of the amounts of L and other conditions gave rise to system B, a much more potent system with the Ru loading as low as 0.25 mol%. Moreover, an NHC-Ru-carbonate complex 6 was identified from the refluxing toluene of 1 and Cs2CO3, and further investigations revealed that 6 was an important intermediate for this catalytic reaction. Based on the above results, we claimed that the role of Cs2CO3 was to facilitate the formation of key intermediate 6. On the other hand, it provided the optimized basicity for the selective amide formation.
- Wang, Wan-Qiang,Yuan, Ye,Miao, Yang,Yu, Bao-Yi,Wang, Hua-Jing,Wang, Zhi-Qin,Sang, Wei,Chen, Cheng,Verpoort, Francis
-
-
- Double carbonylation of iodoarenes in the presence of a pyridinium SILP-Pd catalyst
-
The efficiency of a palladium catalyst, immobilised on a supported ionic liquid phase (SILP) with adsorbed 1-butyl-4-methylpyridinium chloride, was investigated in aminocarbonylation reactions. Double carbonylation was found to be the main reaction using different iodoarenes and aliphatic amines as substrates. Application of aniline derivatives as nucleophiles led to the exclusive formation of substituted benzamides. The stabilisation effect of the adsorbed pyridinium ionic liquid was compared to that of imidazolium and phosphonium derivatives. It was proved that the pyridinium SILP-palladium catalyst could be reused in at least 10 cycles. Recyclability was tested in five successive runs for all of the substrates.
- Nagy, Enik?,Nagy, Petra,Papp, Máté,Skoda-F?ldes, Rita,Urbán, Béla
-
-
- Amidation of Aldehydes with Amines under Mild Conditions Using Metal-Organic Framework Derived NiO@Ni Mott-Schottky Catalyst
-
Here we report a facile method for the synthesis of nickel oxide-nickel (NiO@Ni) Mott-Schottky catalyst employing metal-organic framework (MOF) as the precursor. A direct amidation protocol of aldehydes with amines has been optimized under mild conditions using NiO@Ni Mott-Schottky catalyst and it shows far better catalytic activity than the NiO?Ni nanoparticles prepared from simple Ni2+ salt under similar reaction conditions. The heterogeneous catalyst is robust, recyclable and efficient to provide comparable yield to costly ligand-based homogeneous Ni catalysts. The scope of the reaction protocol has been explored with variably substituted substrates. The reaction initiates by homolytic cleavage of peroxide and proceeds through radical mechanism.
- Goel, Bharat,Vyas, Ved,Tripathi, Nancy,Kumar Singh, Ajit,Menezes, Prashanth W.,Indra, Arindam,Jain, Shreyans K.
-
p. 5743 - 5749
(2020/09/09)
-
- Electrochemical Amide Bond Formation from Benzaldehydes and Amines: Oxidation by Cathodic-Generated Hydrogen Peroxide
-
Although amide bond formation from aldehydes and amines is a popular synthetic tool, most of the previously reported reactions depend on transition-metal catalysts or expensive oxidants. We considered that a more environmentally benign and safer approach could be achieved by electrochemistry. Nineteen benzamide derivatives were obtained with this reaction. NMR studies, cyclic voltammetry (CV) investigations, and control experiments showed that the corresponding intermediate, a hemiaminal, was transformed into the amide by oxidation with hydrogen peroxide generated in situ by cathodic reduction of molecular oxygen.
- Kurose, Yuma,Imada, Yasushi,Okada, Yohei,Chiba, Kazuhiro
-
supporting information
p. 3844 - 3846
(2020/06/23)
-
- DECONSTRUCTIVE FUNCTIONALIZATION METHODS AND COMPOUNDS
-
Disclosed herein, inter alia, are deconstructive functionalization methods and compounds made using the same.
- -
-
Paragraph 0435; 0436
(2020/01/31)
-
- Ruthenium(II)-catalyzed C-H arylation of N,N-dialkyl thiobenzamides with boronic acids by sulfur coordination in 2-MeTHF
-
We report ruthenium(II)-catalyzed ortho-C-H arylation of N,N-dialkylthiobenzamides with boronic acids. The method employs [RuCl2(p-cym)]2 in the presence of Cu(OTf)2 and Ag2O oxidant. The reaction represents the first example of Ru-catalyzed C-H arylation directed by sulfur-containing groups and a rare example of C-H arylation directed by the versatile thiobenzamide moiety. As a further advantage, the method is performed in sustainable and eco-friendly 2-MeTHF as a solvent.
- Zhang, Jin,Liu, Ying,Jia, Qiangqiang,Wang, Yue,Ma, Yangmin,Szostak, Michal
-
supporting information
p. 6884 - 6890
(2020/09/15)
-
- Solvent-free iron(III) chloride-catalyzed direct amidation of esters
-
Amide functional groups are prominent in a broad range of organic compounds with diverse beneficial applications. In this work, we report the synthesis of these functional groups via an iron(iii) chloride-catalyzed direct amidation of esters. The reactions are conducted under solvent-free conditions and found to be compatible with a range of amine and ester substrates generating the desired amides in short reaction times and good to excellent yields at a catalyst loading of 15 mol%.
- Mkhonazi, Blessing D.,Shandu, Malibongwe,Tshinavhe, Ronewa,Simelane, Sandile B.,Moshapo, Paseka T.
-
supporting information
(2020/03/17)
-
- Amine-Mediated Bond Cleavage in Oxidized Lignin Models
-
Introducing amines/ammonia into lignin cracking will allow novel bond cleavage pathways. Herein, a method of amines/ammonia-mediated bond cleavage in oxidized lignin β-O-4 models was studied using a copper catalyst at room temperature, demonstrating the effect of the amine source on the selectivity of products. For primary and secondary aliphatic amines, lignin ketone models underwent oxidative Cα?Cβ bond cleavage and Cα?N bond formation to generate aromatic amides. For ammonia, the competition between oxygen and ammonia determined the selectivity between Cα?N and Cβ?N bond formation, generating amides and α-keto amides, respectively. For tertiary amines, the lignin models underwent oxidative Cα?Cβ bond cleavage to benzoic acids. Control experiments indicated that amines act as nucleophiles attacking at the Cα or Cβ position of the oxidized β-O-4 linkage to be cleaved. This study represents a novel example that the breakage of oxidized lignin model can be regulated by amines with a copper catalyst.
- Li, Hongji,Liu, Meijiang,Liu, Huifang,Luo, Nengchao,Zhang, Chaofeng,Wang, Feng
-
p. 4660 - 4665
(2020/07/04)
-
- IrIII-Catalyzed direct syntheses of amides and esters using nitriles as acid equivalents: A photochemical pathway
-
An unprecedented IrIII[df(CF3)ppy]2(dtbbpy)PF6-catalyzed simple photochemical process for direct addition of amines and alcohols to the relatively less reactive nitrile triple bond is described herein. Various amides and esters are synthesized as the reaction products, with nitriles being the acid equivalents. A mini-library of different types of amides and esters is made using this mild and efficient process, which uses only 1 mol% of photocatalyst under visible light irradiation (λ = 445 nm). The reaction strategy is also efficient for gram-scale synthesis.
- Talukdar, Ranadeep
-
supporting information
p. 5303 - 5308
(2020/04/17)
-
- Supramolecular Pd(II) complex of DPPF and dithiolate: An efficient catalyst for amino and phenoxycarbonylation using Co2(CO)8 as sustainable C1 source
-
Highly active, efficient and robust “dppf ligated tetranuclear palladium dithiolate complex” was synthesized and applied as a catalyst for chemical fixation of carbon monoxide for the synthesis value added chemicals such as tertiary amide and aromatic esters. The synthesized catalyst was characterized using different analytical techniques such as elemental analysis, 1H and 31P NMR spectroscopy. The use of Co2(CO)8 as a cheap, less toxic and low melting solid surrogate are additional advantages over the current protocol. The catalyst showed superior activity towards the Amino (10?3 mol % catalyst) and Phenoxycarbonylation (10-2 mol % catalyst) and high TON (104 to 103) and TOF (103 to 102 h-1). The Betol and Lintrin (active drug molecules) were synthesized under an optimized reaction condition. The scalability of the current protocol has been demonstrated up-to the gram level.
- Gaikwad, Vinayak V.,Mane, Pravin A.,Dey, Sandip,Patel, Divya,Bhanage, Bhalchandra M.
-
-
- Palladium-Catalyzed Desulfurative Amide Formation from Thioureas and Arylboronic Acids
-
The development of the reactivity on carbene complexes would lead to the creation of novel synthetic strategies. We discovered herein the Pd-catalyzed desulfurative amide formation involved Suzuki-Miyaura coupling reaction, notably the Pd complex was generated in situ from thioureas, Ag salt and Pd catalyst. Silver salt was essential for the construction of this type of carbenes from available and stable thioureas and well participated in the catalytic cycle. We report a method for the synthesis of arylamides from arylboronic acids, which greatly enriched the application of thiourea chemistry and expanded the application of the Suzuki-Miyaura coupling.
- Su, Jianke,Li, Wendong,Li, Xin,Xu, Jian,Song, Qiuling
-
p. 5664 - 5668
(2020/10/02)
-
- Copper-catalyzed aerobic oxidative C-C bond cleavage of simple ketones for the synthesis of amides
-
A Cu-catalyzed oxidative amidation of simple ketones with amines via carbon-carbon (C-C) bond cleavage has been developed. A number of aryl and alkyl ketones could be easily converted to amides using cheap copper salt as the catalyst and O2 as the oxidant with a wide range of amines, including primary and secondary amines. This method shows a notable advantage of the broad scope for the substrate, thus providing a practical approach to amides. A plausible mechanism is proposed based on the preliminary experiments.
- Li, Ke,Liu, Wei,Liu, Yu-Feng,Yang, Guo-Ping,Zeng, Kai
-
p. 6958 - 6964
(2020/10/02)
-
- Metal-Free Transamidation of Secondary Amides by N-C Cleavage
-
Transamidation reactions represent a fundamental chemical process involving conversion of one amide functional group into another. Herein, we report a facile, highly chemoselective method for transamidation of N-tert-butoxycarbonylation (N-Boc) activated secondary amides that proceeds under exceedingly mild conditions in the absence of any additives. Because this reaction is performed in the absence of metals, oxidants, or reductants, the reaction tolerates a large number of useful functionalities. The reaction is compatible with diverse amides and nucleophilic amines, affording the transamidation products in excellent yields through direct nucleophilic addition to the amide bond. The utility of this methodology is highlighted in the synthesis of Tigan, a commercial antiemetic, directly from the amide bond. We expect that this new metal-free transamidation will have broad implications for the development of new transformations involving direct nucleophilic addition to the amide bond as a key step.
- Rahman, Md. Mahbubur,Li, Guangchen,Szostak, Michal
-
p. 12091 - 12100
(2019/10/11)
-
- Visible Light-Driven, One-pot Amide Synthesis Catalyzed by the B12 Model Complex under Aerobic Conditions
-
A visible light responsive catalytic system with the B12 complex as the catalyst and [Ir(dtbbpy)(ppy)2]PF6 as the photosensitizer was developed. It provides a convenient and efficient way to synthesize amides. Based on this method, trichlorinated organic compounds were converted into amides in the presence of an amine under aerobic conditions at room temperature in a one-pot procedure. Various trichlorinated organic compounds and an amine source, such as primary, secondary, and cyclic amines, have been evaluated for this transformation, providing the expected products in moderate to excellent yields. Notably, product formation depended on the reaction atmosphere where the amide was obtained under aerobic conditions while partially dechlorinated products were obtained under anaerobic conditions. As this protocol is free from hazardous reagents, extra additives, noble metals, and dangerous gas, the present method provides a novel and efficient approach for amide synthesis under mild and easily controlled conditions.
- Tian, Hui,Shimakoshi, Hisashi,Ono, Toshikazu,Hisaeda, Yoshio
-
p. 237 - 240
(2018/12/13)
-
- Oxidative amidation of benzyl alcohol, benzaldhyde, benzoic acid styrene and phenyl acetylene catalyzed by ordered mesoporous HKUST-1-Cu: Effect of surface area on oxidative amidation reaction
-
HKUST-1-Cu synthesized in the presence and absence of P-123 trough solvotermal method. After characterization using some different microscopic and spectroscopic techniques such as XRD, FT-IR, SEM, ICP, BET and TEM its catalytic activity was investigated in the oxidative coupling of benzyl alcohol, benzaldhyde, benzoic acid, styrene and phenyl acetylene with N,N-dialkylformamides for the preparation of N,N-dimethylformamides. Different derivatives of tertiary amides were synthesized in moderate to good yields in the presence of just ~0.28?mol% of this catalytic system. Reusability of the synthesized catalysts was examined and catalysts were reusable for 8 times without significant decrease in optimized conditions.
- Mohebali, Haleh,Mahjoub, Ali Reza,Karimi, Meghdad,Heydari, Akbar
-
-
- Development of palladium catalysts immobilized on supported phosphonium ionic liquid phases
-
The application of heterogeneous palladium catalysts supported on phosphonium ion modified silica was investigated in aminocarbonylation reactions of aryl iodides. In contrast to catalysts immobilized on supports decorated with imidazolium ions, the application of phosphonium type supported ionic liquid phases made it possible to carry out double carbonylation with good selectivity in apolar toluene which led to a considerable decrease in the amount of leached palladium. An even better stabilization of the palladium catalyst could be achieved by introducing dicationic organic moieties incorporating both imidazolium and phosphonium ions on the surface of the support. At the same time, the former catalyst, obtained from the supported phosphonium ionic liquid phase was found to be superior in monocarbonylations. The amide products were obtained in good yields by the proper choice of the reaction conditions, such as reaction temperature and pressure and that of the base.
- Urbán, Béla,Skoda-F?ldes, Rita
-
p. 302 - 306
(2018/12/04)
-
- Visible light-induced transformation of aldehydes to esters, carboxylic anhydrides and amides
-
A transition metal- and organophotocatalyst free synthesis of esters, carboxylic anhydrides and amides from aldehydes induced by visible-light has been reported. The proposed methodology can be carried out by the use of sunlight or artificial visible light as a blue LED source. The methodology has a very broad applicability and the desired products are obtained in very satisfactory yields.
- Gaspa, Silvia,Raposo, Inês,Pereira, Leonor,Mulas, Gabriele,Ricci, Pier Carlo,Porcheddu, Andrea,De Luca, Lidia
-
p. 10711 - 10715
(2019/07/15)
-
- Base-Promoted Amidation and Esterification of Imidazolium Salts via Acyl C-C bond Cleavage: Access to Aromatic Amides and Esters
-
Imidazolium salts have been effectively employed as suitable acyl transfer agents in amidation and esterification in organic synthesis. The weak acyl C(O)-C imidazolium bond was exploited to generate acyl electrophiles, which further react with amines and alcohols to afford amides and esters. The broad substrate scope of anilines and benzylic amines and base-promoted conditions are the benefits of this route. Interestingly, phenol, benzylic alcohols, and a biologically active alcohol can also be subjected to esterification under the optimized conditions.
- Karthik, Shanmugam,Muthuvel, Karthick,Gandhi, Thirumanavelan
-
p. 738 - 751
(2019/01/24)
-
- Catalyst-Free, Metal-Free, and Chemoselective Transamidation of Activated Secondary Amides
-
A simple protocol, which is catalyst-free, metal-free, and chemoselective, for transamidation of activated secondary amides in ethanol as solvent under mild conditions is reported. A wide range of amines, amino acids, amino alcohols, and the substituents, which are problematic in catalyzed transamidation, are tolerated in this methodology. The transamidation reaction was successfully extended to water as the medium as well. The present methodology appears to be better than the other catalyzed transamidations reported recently.
- Ramkumar, Rajagopal,Chandrasekaran, Srinivasan
-
p. 921 - 932
(2019/02/10)
-
- Amide bond synthesis via silver(I) N-heterocyclic carbene-catalyzed and tert-butyl hydroperoxide-mediated oxidative coupling of alcohols with amines under base free conditions
-
We present a base free method for amide bond construction via oxidative coupling of alcohols with amines catalyzed by Silver(I) N-heterocyclic carbenes (Ag(I)-NHCs) and mediated by tert-butyl hydroperoxide (TBHP) in ethanol. The results of controlled experiments suggest that the oxidative coupling proceeds through the formation of aldehyde, then subsequent attack by amine to give hemiaminal, which can then be oxidized to amide.
- Balaboina, Ramesh,Thirukovela, Narasimha Swamy,Vadde, Ravinder,Vasam, Chandra Sekhar
-
supporting information
p. 847 - 851
(2019/02/20)
-
- Amide Synthesis from Thiocarboxylic Acids and Amines by Spontaneous Reaction and Electrosynthesis
-
Amide bond formation is one of the most important basic reactions in chemistry. A catalyst-free approach for constructing amide bonds from thiocarboxylic acids and amines was developed. The mechanistic studies showed that the disulfide was the key intermediate for this amide synthesis. Thiobenzoic acids could be automatically oxidized to disulfides in air, thioaliphatic acids could be electro-oxidized to disulfides, and the resulting disulfides reacted with amines to give the corresponding amides. By this method, various amides could be easily synthesized in excellent yields without using any catalyst or activator. The successful synthesis of bioactive compounds also highlights the synthetic utility of this strategy in medicinal chemistry.
- Tang, Li,Matuska, Jack H.,Huang, Yu-Han,He, Yan-Hong,Guan, Zhi
-
p. 2570 - 2575
(2019/06/13)
-
- Carbon bridged bis-amide-based rare-earth amine compound and its preparation and with [...][...] synthesis reaction in the application of the
-
The invention discloses a carbon-bridged diacylamino rare earth amide with a general formula of {LLn[N(SiMe3)2]}2, wherein Ln is a rare earth metal selected from lanthanum, neodymium, samarium and yttrium, L represents a carbon-bridged diacylamino ligand, and n may be 1, 2 or 3 and can represent different ligands. The chemical structural formula of the carbon-bridged diacylamino rare earth amide differs with changes of the rare earth metal and the ligand. The invention targetedly discloses four chemical structural formulas of the rare earth amide as shown in the general formula. The carbon-bridged diacylamino rare earth amide provided by the invention is simple to synthesize, has definite structure and high yield and is easy to separate and purify. The invention also provides a preparation method for the rare earth amide and a method for applying the rare earth amide as a catalyst for catalysis of amidation of aldehyde and amine. The application method has the advantages of mild conditions, high activity, good selectivity, a wide substrate adaptation scope, a small catalyst amount and high product yield.
- -
-
Paragraph 0116; 0117
(2019/04/02)
-