6784-26-5Relevant articles and documents
Access to Unsymmetrically Substituted Diaryl Gold N-Acyclic Carbene (NAC) and N-Heterocyclic Carbene (NHC) Complexes via the Isonitrile Route
Vethacke, Vanessa,Claus, Vanessa,Dietl, Martin C.,Ehjeij, Daniel,Meister, Arne,Huber, Jonas F.,Paschai Darian, Leon K.,Rudolph, Matthias,Rominger, Frank,Hashmi, A. Stephen K.
supporting information, p. 536 - 554 (2021/10/20)
A variety of unsymmetric diaryl gold N-acyclic carbene (NAC) complexes was synthesized via the isonitrile route by three different methods: (a) solvent free in a melt, (b) mechanochemically and (c) in THF at room temperature. The latter method can also be used to synthesize unsaturated gold NHC complexes. These methods overall offer access to a broad array of new complexes and remove one of the previous limitations of the isonitrile route to NAC and NHC complexes of gold, namely the inability to react with the less nucleophilic aromatic amines. The new complexes also proved to be successful as pre-catalysts in the gold-catalyzed phenol synthesis. (Figure presented.).
Olefin functionalized IPr.HCl monomer as well as preparation method and application thereof
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Paragraph 0069-0073; 0075; 0078, (2021/06/21)
The invention relates to an olefin functionalized IPr.HCl monomer, a preparation method thereof, a method for preparing an N-heterocyclic carbene functionalized organic polymer (PS-IPr-x) by using the olefin functionalized IPr.HCl monomer, and application of the N-heterocyclic carbene functionalized organic polymer as a heterogeneous catalyst for catalyzing reduction N-formylation of carbon dioxide and amine. A heterogeneous catalyst is prepared by using cheap and easily available DVB as a polymerization cross-linking agent through an AIBN-initiated olefin polymerization method, and has the advantages of low preparation cost and simple preparation method. Meanwhile, the catalytic activity of the catalyst is obviously higher than that of reported catalysts, and the catalyst has a wide practical application prospect.
Zinc Hydride Catalyzed Chemoselective Hydroboration of Isocyanates: Amide Bond Formation and C=O Bond Cleavage
Sahoo, Rajata Kumar,Sarkar, Nabin,Nembenna, Sharanappa
supporting information, p. 11991 - 12000 (2021/04/19)
Herein, a remarkable conjugated bis-guanidinate (CBG) supported zinc hydride, [{LZnH}2; L={(ArHN)(ArN)?C=N?C=(NAr)(NHAr); Ar=2,6-Et2-C6H3}] (I) catalyzed partial reduction of heteroallenes via hydroboration is r
Building N-Heterocyclic Carbene into Triazine-Linked Polymer for Multiple CO2 Utilization
Yue, Chengtao,Wang, Wenlong,Li, Fuwei
, p. 5996 - 6004 (2020/10/06)
The development of new CO2 detection technologies and CO2 “capture-conversion” materials is of great significance due to the growing environmental crisis. Here, multifunctional triazine-linked polymers with built-in N-heterocyclic carbene (NHC) sites (designated as NHC-triazine@polymer) are presented for simultaneous CO2 detection, capture, activation, and catalytic conversion. NHC-triazine@polymer were readily obtained through polymerization of cyanophenyl-substituted NHC. The obtained film-like polymers exhibited interesting CO2-triggered fluorescence “turn-on” response and CO2-sensitive reversible color change. Both NHC and triazine sites could act as efficient binding sites for CO2, and the CO2 uptake of NHC and triazine reached 1.52 and 1.36 mmol g?1, respectively. Notably, after being captured by NHC, CO2 was activated into a zwitterionic adduct NHC?CO2 that could be easily transformed into cyclic carbonate in the presence of epoxides. Moreover, NHC-triazine@polymer were stable and active catalysts for the conversion of low-concentration CO2 in a gas mixture (7 vol %) into cyclic carbonates as well as for hydrosilylation of CO2 to formamides.
Palladium-Catalyzed Diarylation of Isocyanides with Tetraarylleads for the Selective Synthesis of Imines and α-Diimines
Tran, Cong Chi,Kawaguchi, Shin-Ichi,Kobiki, Yohsuke,Matsubara, Hitomi,Tran, Dat Phuc,Kodama, Shintaro,Nomoto, Akihiro,Ogawa, Akiya
, p. 11741 - 11751 (2019/10/02)
Using tetraaryllead compounds (PbAr4) as arylating reagents, isocyanides undergo selective diarylation in the presence of palladium catalysts such as Pd(OAc)2 or Pd(PPh3)4 to afford imines and/or α-diimines based on the isocyanide employed. With aliphatic isocyanides, imines are obtained preferentially, whereas α-diimines are formed in the case of electron-rich aromatic isocyanides. The differences in imine/α-diimine selectivity can be attributed to the stability of imidoylpalladium intermediates formed in this catalytic reaction. Compared with other arylating reagents, tetraaryllead compounds are excellent candidates for use in the selective transformations to imines and/or α-diimines, especially in terms of inhibiting the oligomerization of isocyanides, which results in a lower product selectivity in many transition-metal-catalyzed reactions of isocyanides.
Selective formylation or methylation of amines using carbon dioxide catalysed by a rhodium perimidine-based NHC complex
Lam, Raphael H.,McQueen, Caitlin M. A.,Pernik, Indrek,McBurney, Roy T.,Hill, Anthony F.,Messerle, Barbara A.
supporting information, p. 538 - 549 (2019/02/14)
Carbon dioxide can play a vital role as a sustainable feedstock for chemical synthesis. To be viable, the employed protocol should be as mild as possible. Herein we report a methodology to incorporate CO2 into primary, secondary, aromatic or alkyl amines catalysed by a Rh(i) complex bearing a perimidine-based NHC/phosphine pincer ligand. The periminide-based ligand belongs to a class of 6-membered NHC ligand accessed through chelate-assisted double C-H activation. N-Formylation and -methylation of amines were performed using a balloon of CO2, and phenylsilane as the reducing agent. Product selectivity between formylated and methylated products was tuned by changing the solvent, reaction temperature and the quantity of phenylsilane used. Medium to excellent conversions, as well as tolerance to a range of functional groups, were achieved. Stoichiometric reactions with reactants employed in catalysis and time course studies suggested that formylation and methylation reactions of interest begin with hydrosilylation of CO2 followed by reaction with amine substrates.
Consecutive Lossen rearrangement/transamidation reaction of hydroxamic acids under catalyst- and additive-free conditions
Jia, Mengmeng,Zhang, Heng,Lin, Yongjia,Chen, Dimei,Chen, Yanmei,Xia, Yuanzhi
, p. 3615 - 3624 (2018/05/26)
The Lossen rearrangement is a classic process for transforming activated hydroxamic acids into isocyanate under basic or thermal conditions. In the current report we disclosed a consecutive Lossen rearrangement/transamidation reaction in which unactivated hydroxamic acids were converted into N-substituted formamides in a one-pot manner under catalyst- and additive-free conditions. One feature of this novel transformation is that the formamide plays triple roles in the reaction by acting as a readily available solvent, a promoter for additive-free Lossen rearrangement, and a source of the formyl group in the final products. Acyl groups other than formyl could also be introduced into the product when changing the solvent to other low molecular weight aliphatic amide derivatives. The solvent-promoted Lossen rearrangement was better understood by DFT calculations, and the intermediacy of isocyanate and amine was supported well by experiments, in which the desired products were obtained in excellent yields under similar conditions. Not only monosubstituted formamides were synthesized from hydroxamic acids, but also N,N-disubstituted formamides were obtained when secondary amines were used as precursors.
Porous Organic Polymers with Built-in N-Heterocyclic Carbenes: Selective and Efficient Heterogeneous Catalyst for the Reductive N-Formylation of Amines with CO2
Lv, Hui,Wang, Wenlong,Li, Fuwei
, p. 16588 - 16594 (2018/10/24)
A series of porous organic polymers (POPs) based on N-heterocyclic carbene (NHC) building blocks has been prepared through an octacarbonyldicobalt complex [Co2(CO)8]-catalyzed trimerization of terminal alkyne groups. By changing the monomer ratio in the copolymerization, cross-linked POPs with tunable surface areas of 485–731 m2 g?1 and pore volumes of 0.31–0.51 cm3 g?1 were easily prepared. Compared with the analogues homogeneous NHC (SIPr) catalysts, the POPs exhibited an enhanced catalytic activity and high selectivity in the reductive functionalization of CO2 with amines. The extraordinary performance of the sample could be attributed to the combination of the gas enrichment (or storage) effect, enhanced in-pore concentrations of other substrates, and advantageous micropore structures of the porous polymers. Meanwhile, these catalysts can easily be separated and recycled from the reaction systems with only a slight loss of activity. This excellent catalytic performance and facile recycling of heterogeneous catalysts make them very attractive. These NHC-containing POPs may provide a new platform for catalytic transformations of CO2.
Catalyst-free: N -formylation of amines using BH3NH3 and CO2 under mild conditions
Zhao, Tian-Xiang,Zhai, Gao-Wen,Liang, Jian,Li, Ping,Hu, Xing-Bang,Wu, You-Ting
supporting information, p. 8046 - 8049 (2017/07/22)
The catalyst-free N-formylation of amines using CO2 as the C1 source and BH3NH3 as the reductant has been developed for the first time. The corresponding formylated products of both primary and secondary amines are obtained in good to excellent yields (up to 96% of isolated yield) under mild conditions.
Electrostatic Catalyst Generated from Diazadiborinine for Carbonyl Reduction
Wu, Di,Wang, Ruixing,Li, Yongxin,Ganguly, Rakesh,Hirao, Hajime,Kinjo, Rei
supporting information, p. 134 - 151 (2017/07/17)
Since the seminal discovery by van der Waals in the late 19th century that weak attractive forces exist between even electrically neutral atoms or molecules, a number of noncovalent interactions have been recognized. Among them, electrostatic interactions such as hydrogen bonds play pivotal roles in countless chemical processes and biochemical living systems. By mimicking biocatalysis, various organocatalysts equipped with hydrogen-bond functionality have been developed; however, a challenge has persisted in designing catalysts exploiting other types of noncovalent interactions. Here, we report metal-free hydroboration reactions of carbonyl compounds and CO2 catalyzed by aromatic diazadiborinine. A joint experimental and computational study on the reaction mechanism suggests that adducts of diazadiborinine with carbonyl and CO2 formed at the initial stage of the reactions serve as actual catalysts. The former stabilizes the transition state by using the electrostatic interaction between the hydride of borane and the polar, hole-shaped structure of the adduct.
