- Suzuki-Miyaura cross-coupling of esters by selective O-C(O) cleavage mediated by air- And moisture-stable [Pd(NHC)(μ-Cl)Cl]2precatalysts: Catalyst evaluation and mechanism
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The cross-coupling of aryl esters has emerged as a powerful platform for the functionalization of otherwise inert acyl C-O bonds in chemical synthesis and catalysis. Herein, we report a combined experimental and computational study on the acyl Suzuki-Miyaura cross-coupling of aryl esters mediated by well-defined, air- and moisture-stable Pd(ii)-NHC precatalysts [Pd(NHC)(μ-Cl)Cl]2. We present a comprehensive evaluation of [Pd(NHC)(μ-Cl)Cl]2 precatalysts and compare them with the present state-of-the-art [(Pd(NHC)allyl] precatalysts bearing allyl-type throw-away ligands. Most importantly, the study reveals [Pd(NHC)(μ-Cl)Cl]2 as the most reactive precatalysts discovered to date in this reactivity manifold. The unique synthetic utility of this unconventional O-C(O) cross-coupling is highlighted in the late-stage functionalization of pharmaceuticals and sequential chemoselective cross-coupling, providing access to valuable ketone products by a catalytic mechanism involving Pd insertion into the aryl ester bond. Furthermore, we present a comprehensive study of the catalytic cycle by DFT methods. Considering the clear advantages of [Pd(NHC)(μ-Cl)Cl]2 precatalysts on several levels, including facile one-pot synthesis, superior atom-economic profile to all other Pd(ii)-NHC catalysts, and versatile reactivity, these should be considered as the 'first-choice' catalysts for all routine applications in ester O-C(O) bond activation.
- Cavallo, Luigi,Nolan, Steven P.,Poater, Albert,Szostak, Michal,Yang, Shiyi,Zhou, Tongliang
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p. 3189 - 3197
(2021/05/25)
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- Selective Oxidation of Alkylarenes to the Aromatic Ketones or Benzaldehydes with Water
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Here a palladium-catalyzed oxidation method for converting alkylarenes into the aromatic ketones or benzaldehydes with water as the only oxygen donor is reported. This C-H bond oxidation functionalization does not require other oxidants and hydrogen accep
- Du, Jihong,Duan, Baogen,Liu, Kun,Liu, Renhua,Yu, Feifei,Yuan, Yongkun,Zhang, Chenyang,Zhang, Jin
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supporting information
(2022/02/09)
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- Catalytic Aldehyde and Alcohol Arylation Reactions Facilitated by a 1,5-Diaza-3,7-diphosphacyclooctane Ligand
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We report a catalytic method to access secondary alcohols by the coupling of aryl iodides. Either aldehydes or alcohols can be used as reaction partners, making the transformation reductive or redox-neutral, respectively. The reaction is mediated by a Ni catalyst and a 1,5-diaza-3,7-diphosphacyclooctane. This P2N2ligand, which has previously been unrecognized in cross-coupling and related reactions, was found to avoid deleterious aryl halide reduction pathways that dominate with more traditional phosphines and NHCs. An interrupted carbonyl-Heck type mechanism is proposed to be operative, with a key 1,2-insertion step forging the new C-C bond and forming a nickel alkoxide that may be turned over by an alcohol reductant. The same catalyst was also found to enable synthesis of ketone products from either aldehydes or alcohols, demonstrating control over the oxidation state of both the starting materials and products.
- Isbrandt, Eric S.,Nasim, Amrah,Newman, Stephen G.,Zhao, Karen
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supporting information
p. 14646 - 14656
(2021/09/18)
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- Acyl radicals from α-keto acids using a carbonyl photocatalyst: Photoredox-catalyzed synthesis of ketones
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Acyl radicals have been generated from α-keto acids using inexpensive and commercially available 2-chloro-thioxanthen-9-one as the photoredox catalyst under visible light illumination. These reactive species added to olefins or coupled with aryl halides via a bipyridylstabilized Ni(II) catalyst, enabling easy access to a diverse range of ketones. This reliable, atom-economical, and eco-friendly protocol is compatible with a wide range of functional groups.
- Zhu, Da-Liang,Wu, Qi,Young, David James,Wang, Hao,Ren, Zhi-Gang,Li, Hong-Xi
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supporting information
p. 6832 - 6837
(2020/10/12)
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- Selective Acylation of Aryl- A nd Heteroarylmagnesium Reagents with Esters in Continuous Flow
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A selective acylation of readily accessible organomagnesium reagents with commercially available esters proceeds at convenient temperatures and short residence times in continuous flow. Flow conditions allow us to prevent premature collapse of the hemiacetal intermediates despite noncryogenic conditions, thus furnishing ketones in good yields. Throughout, the coordinating ability of the ester and/or Grignard was crucial for the reaction outcome. This was leveraged by the obtention of several bisaryl ketones using 2-hydroxy ester derivatives as substrates.
- Heinz, Benjamin,Djukanovic, Dimitrije,Ganiek, Maximilian A.,Martin, Benjamin,Schenkel, Berthold,Knochel, Paul
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supporting information
p. 493 - 496
(2020/01/31)
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- Xantphos-ligated palladium dithiolates: An unprecedented and convenient catalyst for the carbonylative Suzuki–Miyaura cross-coupling reaction with high turnover number and turnover frequency
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Xantphos- and dithiolate-ligated macrocyclic palladium complexes as an efficient and stable catalyst for the carbonylative Suzuki–Miyaura cross-coupling reaction have been synthesized. The catalysts were characterized by 1H-nuclear magnetic resonance (NMR), CHNS (carbon, hydrogen, nitrogen, and sulfur) analysis, melting point analysis, and 31P-NMR spectroscopy. Several sensitive functional groups (e.g., –NO2, –F, –Cl, –Br, –NH2, and –CN) on the aromatic ring were well tolerated in the carbonylative Suzuki–Miyaura coupling reaction. The present palladium complexes produce six times higher turnover number (TON) and five times higher turnover frequency (TOF) compared with conventional homogeneous palladium precursors. Maximum TONs in the range of 105 to 106 and TOF in the range of 104 to 105 could be generated by a very low amount of catalyst loading (10–5?mol%).
- Gaikwad, Vinayak V.,Mane, Pravin A.,Dey, Sandip,Bhanage, Bhalchandra M.
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- Efficient construction of C–C bonds from aryl halides/aryl esters with arylboronic acids catalysed by palladium(II) thiourea complexes
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A new set of palladium(II) complexes comprising phenyl(thiazolyl)thiourea ligands have been successfully synthesized and characterized with the aid of analytical as well as spectral (IR, UV–visible and NMR) methods. A distorted square-planar geometry with N^S coordination mode of thiourea ligands in the new palladium complexes was corroborated by single-crystal X-ray diffraction methods. Interestingly, the palladium(II) thiourea complexes showed the highest catalytic activity with 0.1 mol% catalyst loading in Suzuki–Miyaura cross-coupling reactions utilizing a range of aryl bromides/unactivated aryl chlorides with arylboronic acids as coupling partners in aqueous–organic media. Syntheses of diaryl ketones using aryl esters and arylboronic acids as coupling partners were also achieved with low catalyst loading within 20 h. The potential of our catalyst was demonstrated by its wide substrate scope, low catalyst loadings and high isolated yield. Moreover, the influences of key parameters like solvent, base, temperature and catalyst loading were also investigated.
- Thimma Sambamoorthy, Manikandan,Rengan, Ramesh,Jan Grzegorz, Malecki
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- Palladium-Catalyzed Direct Oxidative Coupling of Iodoarenes with Primary Alcohols Leading to Ketones: Application to the Synthesis of Benzofuranones and Indenones
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In the present study, a palladium-catalyzed direct oxidative acylation through cross-dehydrogenative coupling has been investigated, utilizing readily available primary alcohols as acylating sources. Overall, this oxidative coupling proceeds via three distinct transformations such as oxidation, radical formation, and cross-coupling in one catalytic process. This protocol does not involve the assistance of a directing group or activation of the carbonyl group by any other means. Furthermore, this reaction made use of no toxic CO gas as carbonylating agent; instead, feedstock primary alcohols have been utilized as acylation source. Notably, the synthesis of benzofuranones and indenones is enabled. This strategy was also applied to the synthesis of n-butylphthalide, fenofibrate, pitofenone, and neo-lignan.
- Suchand, Basuli,Sreenivasulu, Chinnabattigalla,Satyanarayana, Gedu
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p. 4832 - 4843
(2019/07/31)
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- N-Acyl-5,5-dimethylhydantoin, a New Mild Acyl-Transfer Reagent in Pd Catalysis: Highly Efficient Synthesis of Functionalized Ketones
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The palladium-catalyzed Suzuki-Miyaura cross-coupling of N-acyl-5,5-dimethylhydantoins with arylboronic acids has been developed via selective amides C-N bond cleavage. The new reagent is commercially available and air-/moisture-stable, and it offers a variety of ketones in good yields through Suzuki coupling under mild conditions (up to 95%).
- Luo, Zhongfeng,Liu, Tingting,Guo, Weijie,Wang, Zijia,Huang, Jingjun,Zhu, Yulin,Zeng, Zhuo
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p. 1188 - 1199
(2018/09/06)
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- MeZnOMe-mediated reaction of aldehydes with Grignard reagents: A glance into nucleophilic addition/Oppenauer oxidation pathway
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A novel organozincate of RMgX ?MeZnOMe ?LiCl type, formed in situ via transmetalation of Grignard reagent RMgBr ?LiCl with MeZnOMe, is shown to be an excellent organometallic species in the nucleophilic addition/Oppenauer oxidation of aldehydes to generate aromatic ketones in high yield. This transformation allows quick access to structurally diverse aryl, heteroaryl, benzyl and alkyl ketones with broad substrate scope and excellent functional group tolerance.
- Fu, Ying,Ma, Xian-Zhen,Shi, Chun-Zhao,Shen, Tong,Du, Zhengyin
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- Kumada Arylation of Secondary Amides Enabled by Chromium Catalysis for Unsymmetric Ketone Synthesis under Mild Conditions
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The synthesis of aromatic ketones by chromium-catalyzed Kumada arylation of secondary amides with organomagnesium reagents is described. This reaction was enabled by using low-cost chromium(III) salt as a precatalyst, combined with trimethylsilyl chloride
- Chen, Changpeng,Liu, Pei,Luo, Meiming,Zeng, Xiaoming
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p. 5864 - 5868
(2018/05/29)
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- Ni/Ti Dual Catalytic Cross-Coupling of Nitriles and Organobromides to Access Ketones
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Herein, we report the development of a dual catalytic approach for the cross-coupling of nitriles with aryl- and aliphatic-bromides. A titanium(III) catalyst is used to activate nitriles enabling their coupling with organobromides through a nickel catalyst. The Ni/Ti system efficiently prepared unsymmetrical ketones with good chemoselectivity and could selectively couple a bromide in the presence of other functionalizable handles.
- Chenniappan, Vinoth Kumar,Silwal, Sajan,Rahaim, Ronald J.
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p. 4539 - 4544
(2018/05/23)
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- Hydrogen bond donor solvents enabled metal and halogen-free Friedel–Crafts acylations with virtually no waste stream
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We have developed a metal and halogen-free Friedel–Crafts acylation protocol with virtually no waste stream generation. We propose a hydrogen bonding donor solvent will form a hydrogen bonding network and may provide significant rate enhancement for Friedel–Crafts reactions. Trifluoroacetic acid is one of the strongest H-bond donor solvents, which is also volatile and can be easily recovered by distillation without need for reaction workup. Our protocol is a ‘green’ Friedel–Crafts acylation process: 1) the catalyst can be recovered and reused; 2) using halogen free starting material (carboxylic acids anhydride or carboxylic acids); 3) no need for aqueous reaction work-up; 4) minimum or no waste steam generation.
- Liu, Guangchang,Xu, Bo
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supporting information
p. 869 - 872
(2018/02/09)
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- Palladium-catalyzed synthesis of diaryl ketones from aldehydes and (hetero)aryl halides via C-H bond activation
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We developed a palladium-catalyzed C-H transformation that enabled the synthesis of ketones from aldehydes and (hetero)aryl halides. The use of picolinamide ligands was key to achieving the transformation. Heteroaryl ketones, as well as diaryl ketones, were synthesized in good to excellent yields, even in gram-scale, using this reaction. Results of density functional theory (DFT) calculations support the C-H bond activation pathway.
- Wakaki, Takayuki,Togo, Takaya,Yoshidome, Daisuke,Kuninobu, Yoichiro,Kanai, Motomu
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p. 3123 - 3128
(2018/04/14)
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- General Method for the Suzuki-Miyaura Cross-Coupling of Primary Amide-Derived Electrophiles Enabled by [Pd(NHC)(cin)Cl] at Room Temperature
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A general, highly selective method for the room temperature Suzuki-Miyaura cross-coupling of commonly encountered primary benzamides is reported. A combination of site-selective N,N-di-Boc-activation (tert-butoxycarbonyl activation) of the amide nitrogen with practical air- and moisture-stable, well-defined, and highly reactive [Pd(NHC)(cin)Cl] (NHC = N-heterocyclic carbene; cin = cinnamyl) provides a highly effective route to biaryl ketones from primary amides in high yields. For the first time, a TON of >1000 has been achieved in amide acyl cross-coupling.
- Lei, Peng,Meng, Guangrong,Ling, Yun,An, Jie,Nolan, Steven P.,Szostak, Michal
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supporting information
p. 6510 - 6513
(2017/12/26)
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- N-Methylamino Pyrimidyl Amides (MAPA): Highly Reactive, Electronically-Activated Amides in Catalytic N-C(O) Cleavage
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Despite recent progress in catalytic cross-coupling technologies, the direct activation of N-alkyl-N-aryl amides has been a challenging transformation. Here, we report the first Suzuki cross-coupling of N-methylamino pyrimidyl amides (MAPA) enabled by the controlled nN → πAr conjugation and the resulting remodeling of the partial double bond character of the amide bond. The new mode of amide activation is suitable for generating acyl-metal intermediates from unactivated primary and secondary amides.
- Meng, Guangrong,Lalancette, Roger,Szostak, Roman,Szostak, Michal
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p. 4656 - 4659
(2017/09/12)
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- Suzuki-Miyaura Cross-Coupling of N-Acylpyrroles and Pyrazoles: Planar, Electronically Activated Amides in Catalytic N-C Cleavage
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The formation of C-C bonds from amides by catalytic activation of the amide bond has been thus far possible by steric distortion. Herein, we report the first example of a general Pd-catalyzed Suzuki-Miyaura cross-coupling of planar amides enabled by the combination of (i) electronic-activation of the amide nitrogen in N-acylpyrroles and pyrazoles and (ii) the use of a versatile Pd-NHC catalysis platform. The origin and selectivity of forming acylmetals, including the role of twist, are discussed.
- Meng, Guangrong,Szostak, Roman,Szostak, Michal
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p. 3596 - 3599
(2017/07/15)
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- Pd-PEPPSI: Pd-NHC Precatalyst for Suzuki-Miyaura Cross-Coupling Reactions of Amides
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Pd-PEPPSI-IPr serves as a highly reactive precatalyst in the direct Suzuki-Miyaura cross-coupling of amides. An array of amides can be cross-coupled with a range of arylboronic acids in very good yields using a single, operationally simple protocol. The studies described represent the first use of versatile PEPPSI type of Pd-NHC complexes as catalysts for the cross-coupling of amides by N-C bond activation. The method is user-friendly, since it employs a commercially available, air- and moisture-stable Pd-PEPPSI-IPr complex. Pd-PEPPSI-IPr provides a significant improvement over all current Pd/phosphane catalysts for amide N-C bond activation. Mechanistic studies provide insight into the reaction rates of Pd-NHC-catalyzed cross-coupling of different amides, with Pd-PEPPSI-IPr being particularly effective for the cross-coupling of N-Boc carbamates under the developed conditions.
- Lei, Peng,Meng, Guangrong,Ling, Yun,An, Jie,Szostak, Michal
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p. 6638 - 6646
(2017/07/15)
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- General Method for the Suzuki-Miyaura Cross-Coupling of Amides Using Commercially Available, Air- and Moisture-Stable Palladium/NHC (NHC = N-Heterocyclic Carbene) Complexes
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The direct Suzuki-Miyaura cross-coupling of amides catalyzed by Pd-NHC complexes is reported. Using a single protocol, commercially available, air- and moisture-stable (NHC)Pd(R-allyl)Cl complexes can effect Suzuki-Miyaura cross-coupling of a wide range of amides with arylboronic acids in very good yields. The studies described herein represent the use of versatile Pd-NHC complexes as catalysts for transition-metal-catalyzed cross-coupling of amides by N-C bond activation. The Pd-NHC catalysts provide a significant improvement over all current Pd-PR3 systems employed for the amide N-C bond activation. Mechanistic studies provide strong support for the development of a unified reactivity scale of the amide bond for the generation of acyl-metal intermediates.
- Lei, Peng,Meng, Guangrong,Szostak, Michal
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p. 1960 - 1965
(2017/08/14)
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- Palladium-Catalyzed Denitrogenative Synthesis of Aryl Ketones from Arylhydrazines and Nitriles Using O2 as Sole Oxidant
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An efficient and simple palladium-catalyzed approach for the synthesis of aryl ketones from low-cost nitriles and arylhydrazines using molecular oxygen (O2) as sole oxidant via C-N bond cleavage is reported. Various aryl ketones were synthesized in moderate to good yields under mild conditions. A possible mechanism involving the PdII/Pd0 catalytic cycle process is depicted, and a cationic palladium intermediate was detected by ESI-MS.
- Wang, Xu,Huang, Yubing,Xu, Yanli,Tang, Xiaodong,Wu, Wanqing,Jiang, Huanfeng
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p. 2211 - 2218
(2017/02/26)
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- Coupling of aromatic aldehydes with aryl halides in the presence of nickel catalysts with diazabutadiene ligands
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Nickel catalysts with diazabutadiene ligands promote cross-coupling of benzaldehydes with aryl halides in the presence of zinc as reducing agent, which leads to the corresponding benzhydrols and benzophenones. The benzophenone percentage considerably increases when lithium chloride additive is used.
- Asachenko,Valaeva,Kudakina,Uborsky,Izmer,Kononovich,Voskoboynikov
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p. 456 - 463
(2017/03/08)
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- Suzuki Coupling of Amides via Palladium-Catalyzed C–N Cleavage of N-Acylsaccharins
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A palladium-catalyzed cross-coupling of activated amides with arylboronic acids has been developed via C–N bond cleavage. This approach demonstrated high tolerance to a variety of alkyl, aryl, heterocyclic and vinyl substituents. Unsymmetrical ketones could be achieved in excellent yield under mild conditions with 1% catalyst loadings. (Figure presented.).
- Wu, Hongxiang,Li, Yue,Cui, Ming,Jian, Junsheng,Zeng, Zhuo
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p. 3876 - 3880
(2016/12/16)
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- Magnesium salt promoted tandem nucleophilic addition-Oppenauer oxidation of aldehydes with organozinc reagents
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A magnesium salt promoted synthesis of ketones via tandem nucleophilic addition-Oppenauer oxidation of aldehydes using organozinc chemistry was demonstrated. Magnesium salts concomitantly generated via magnesium metal mediated organohalide zincation exhibit high efficacy for nucleophilic addition of organozinc reagents to aromatic aldehydes and thereafter Oppenauer oxidation whereby ketones are formed in high to excellent yields.
- Fu, Ying,Zhao, Xing Ling,Hügel, Hulmet,Huang, Danfeng,Du, Zhengyin,Wang, Kehu,Hu, Yulai
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supporting information
p. 9720 - 9724
(2016/10/31)
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- Palladium-Catalyzed Environmentally Benign Acylation
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Recent trends in research have gained an orientation toward developing efficient strategies using innocuous reagents. The earlier reported transition-metal-catalyzed carbonylations involved either toxic carbon monoxide (CO) gas as carbonylating agent or functional-group-assisted ortho sp2 C-H activation (i.e., ortho acylation) or carbonylation by activation of the carbonyl group (i.e., via the formation of enamines). Contradicting these methods, here we describe an environmentally benign process, [Pd]-catalyzed direct carbonylation starting from simple and commercially available iodo arenes and aldehydes, for the synthesis of a wide variety of ketones. Moreover, this method comprises direct coupling of iodoarenes with aldehydes without activation of the carbonyl and also without directing group assistance. Significantly, the strategy was successfully applied to the synthesis n-butylphthalide and pitofenone.
- Suchand, Basuli,Satyanarayana, Gedu
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p. 6409 - 6423
(2016/08/16)
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- Efficient Synthesis of Diaryl Ketones by Nickel-Catalyzed Negishi Cross-Coupling of Amides by Carbon–Nitrogen Bond Cleavage at Room Temperature Accelerated by a Solvent Effect
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The first Negishi cross-coupling of amides for the synthesis of versatile diaryl ketones by selective C?N bond activation under exceedingly mild conditions is reported. The cross-coupling was accomplished with bench-stable, inexpensive precatalyst [Ni(PPh3)2Cl2] that shows high functional-group tolerance and enables the synthesis of highly functionalized diaryl ketone motifs. The coupling occurred with excellent chemoselectivity favoring the ketone (cf. biaryl) products. Notably, this process represents the mildest conditions for amide N?C bond activation accomplished to date (room temperature, 10 min). Considering the versatile role of polyfunctional biaryl ketone linchpins in modern organic synthesis, availability, and excellent functional-group tolerance of organozinc reagents, this strategy provides a new platform for amide N?C bond/organozinc cross-coupling under mild conditions.
- Shi, Shicheng,Szostak, Michal
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p. 10420 - 10424
(2016/07/21)
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- Nickel N-heterocyclic carbene-catalyzed cross-coupling reaction of aryl aldehydes with organozinc reagents to produce aryl ketones
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The transformation of aromatic aldehydes into aryl ketones by nickel-catalyzed cross-coupling has been developed. This transformation represents an efficient and attractive synthetic utilization of organozinc reagents. The reaction provides a mild, practical method toward the synthesis of aryl ketones which are versatile intermediates and building blocks in organic synthesis.
- Jin, Cheng,Gu, Lijun,Yuan, Minglong
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p. 4341 - 4345
(2015/09/01)
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- Room-Temperature Decarboxylative Couplings of α-Oxocarboxylates with Aryl Halides by Merging Photoredox with Palladium Catalysis
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Enabled by merging iridium photoredox catalysis and palladium catalysis, α-oxocarboxylate salts can be decarboxylatively coupled with aryl halides to generate aromatic ketones and amides at room temperature. DFT calculations suggest that this reaction proceeds through a Pd0-PdII-PdIII pathway, in which the PdIII intermediate is responsible for reoxidizing IrII to complete the IrIII-IrIII-IrII photoredox cycle. Like a mergin': Enabled by merging iridium photoredox catalysis and palladium catalysis, palladium-catalyzed decarboxylative coupling of α-oxocarboxylates with aryl halides can proceed at room temperature. DFT calculations suggest that a Pd0-PdII-PdIII catalytic cycle is merged with an IrIII-IrIII-IrII photoredox cycle, in which PdIII is responsible for oxidizing IrII to complete the photoredox cycle.
- Cheng, Wan-Min,Shang, Rui,Yu, Hai-Zhu,Fu, Yao
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supporting information
p. 13191 - 13195
(2015/09/15)
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- Metal-free, visible-light-mediated transformation of aryl diazonium salts and (hetero)arenes: An efficient route to aryl ketones
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A visible-light-catalyzed synthesis of aryl ketones from aryldiazonium salts, CO and (hetero)arenes at room temperature is discovered. This transformation represents an efficient and attractive synthetic utilization of aryl diazonium salts.
- Gu, Lijun,Jin, Cheng,Liu, Jiyan
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supporting information
p. 3733 - 3736
(2015/07/15)
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- Nickel N-heterocyclic carbene catalyzed C-C bond formation: A new route to aryl ketones
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A novel nickel N-heterocyclic carbene catalyzed cross-coupling reaction of aryl aldehydes with boronic esters for the synthesis of aryl ketones was developed. This reaction provides a mild, practical method toward aryl ketones, which are versatile intermediates and building blocks in organic synthesis.
- Gu, Li-Jun,Jin, Cheng,Zhang, Hong-Tao
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supporting information
p. 8741 - 8744
(2015/06/08)
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- UV light-mediated difunctionalization of alkenes through aroyl radical addition/1,4-/1,2-Aryl shift cascade reactions
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UV light-mediated difunctionalization of alkenes through an aroyl radical addition/1,4-/1,2-aryl shift has been described. The resulted aroyl radical from a photocleavage reaction added to acrylamide compounds followed by cyclization led to the formation of oxindoles, whereas the addition to cinnamic amides aroused a unique 1,4-aryl shift reaction. Furthermore, the difunctionalization of alkenes of prop-2-en-1-ols was also achieved through aroyl radical addition and a sequential 1,2-aryl shift cascade reaction.
- Zheng, Lewei,Huang, Hongli,Yang, Chao,Xia, Wujiong
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p. 1034 - 1037
(2015/03/30)
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- An Efficient synthesis of Weinreb amides and ketones via palladium nanoparticles on ZIF-8 catalysed carbonylative coupling
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Heterogeneously catalysed carbonylative coupling reactions such as aminocarbonylation and Suzuki-carbonylation are reported using Pd nanoparticles supported on ZIF-8 for efficient and environmentally attractive synthesis of Weinreb amides and ketones from aryl bromides or iodides. The catalyst is air stable, offers high activity with very low palladium leaching and is recyclable. The presence of a phosphine ligand was required when aryl bromides were used as substrates, while no ligand was necessary when aryl iodides were used. the Partner Organisations 2014.
- Thanh Dang, Tuan,Chen, Anqi,Majeed Seayad, Abdul
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p. 30019 - 30027
(2014/08/05)
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- Dirhodium(II)-Catalyzed Cross-Coupling Reactions of Aryl Aldehydes with Arylboronic Acids in Water
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In this report, dirhodium(II) catalysts with axial phosphanes ligands were employed to catalyze cross-coupling reactions of aromatic aldehydes with arylboronic acids to generate ketones in neat water. The overall reaction is proposed to occur through a cascade process involving the dirhodium-catalyzed addition of boronic acids to aldehydes followed by the dehydrogenative oxidation of alcohols.
- Kuang, Yi,Wang, Yuanhua
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supporting information
p. 1163 - 1166
(2015/10/05)
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- Tetraethylammonium iodide catalyzed synthesis of diaryl ketones via the merger of cleavage of C-C double bonds and recombination of aromatic groups
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An efficient method for synthesizing diaryl ketones via merging of oxidative cleavage of C-C double bonds and recombination of aromatic groups is developed with Et4NI (2.5 mol%) as the catalyst and NaIO4 as the oxidant. The control experiments provide valuable mechanistic insights into the formation of diaryl ketones, and suggest that NaIO4 serves as an epoxidation and nucleophilic deformylation reagent.
- Zeng, Xianghua,Xu, Daqian,Miao, Chengxia,Xia, Chungu,Sun, Wei
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p. 46494 - 46497
(2014/12/10)
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- Tandem nucleophilic addition-Oppenauer oxidation of aromatic aldehydes to aryl ketones with triorganoaluminium reagents
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In the presence of pinacolone, the in situ prepared triorganoaluminium reagents reacted with aromatic aldehydes to give ketones in moderate to high yield. We propose that the products are formed via a tandem organoaluminium reagents addition-Oppenauer oxidation sequence. The Royal Society of Chemistry 2013.
- Fu, Ying,Yang, Yanshou,Hügel, Helmut M.,Du, Zhengyin,Wang, Kehu,Huang, Danfeng,Hu, Yulai
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supporting information
p. 4429 - 4432
(2013/08/23)
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- Naphthodioxinone-1,3-benzodioxole as photochemically masked one-component type II photoinitiator for free radical polymerization
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A 1,3-benzodioxole derivative of naphthodioxinone, namely 2-(benzo[d][1,3]dioxol-5-yl)-9-hydroxy-2-phenyl-4H-naphtho[2,3-d][1,3] dioxin-4-one was synthesized and characterized. Its capability to act as caged one-component Type II photoinitiator for free r
- Kumbaraci, Volkan,Aydogan, Binnur,Talinli, Naciye,Yagci, Yusuf
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scheme or table
p. 2612 - 2618
(2012/08/13)
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- Palladium-phosphinous acid-catalyzed cross-coupling of aryl and acyl halides with aryl-, alkyl-, and vinylzinc reagents
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(Chemical Equation Presented) Several palladium-phosphinous acids have been prepared and employed in cross-coupling reactions of aryl or acyl halides with aliphatic and aromatic organozinc reagents. The POPd7-catalyzed reaction of aryl halides, including electron-rich aryl chlorides, and arylzinc reagents was found to afford biaryls exhibiting alkoxy, alkylthio, amino, ketone, cyano, nitro, ester, and heteroaryl groups in 75-93% yield. Excellent results were obtained with sterically hindered substrates which gave di- and tri-ortho-substituted biaryls in up to 92% yield. Aryl halides also undergo POPd7-catalyzed aryl-vinyl and aryl-alkyl bond formation under mild conditions. Styrenes and alkylarenes were prepared in 79-93% yield from aryl halides and vinyl or alkylzinc reagents. The replacement of aryl halides by acyl halides provides access to ketones which were produced in up to 98% yield when POPd was used as catalyst. This approach overcomes the limited substrate scope, reduced regiocontrol, and low functional group tolerance of traditional Friedel-Crafts acylation methods.
- Xu, Hanhui,Ekoue-Kovi, Kekeli,Wolf, Christian
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p. 7638 - 7650
(2008/12/22)
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- Palladium-phosphinous acid-catalyzed cross-coupling of aliphatic and aromatic acyl chlorides with boronic acids
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The cross-coupling of aromatic and aliphatic acyl chlorides with arylboronic acids in the presence of 2.5 mol % of (t-Bu2POH)2PdCl2 (POPd) provides rapid access to ketones that are obtained in up to 93% yield. This palladium-phosphinous acid-catalyzed reaction is completed within 10 min when microwave irradiation is used, and it overcomes typical drawbacks of Friedel-Crafts acylation procedures such as harsh reaction conditions, untunable regiocontrol, and low substrate scope.
- Ekoue-Kovi, Kekeli,Xu, Hanhui,Wolf, Christian
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p. 5773 - 5776
(2008/12/22)
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- Cesium hydroxide-promoted aerobic oxidation of sec-aromatic alcohols
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A CsOH-promoted aerobic oxidation of sec-aromatic alcohols has been developed, using air as a free and clean oxidant, and providing aryl ketones in good to excellent yields.
- Zhang, Weiwei,Liu, Miaochang,Wu, Huayue,Ding, Jinchang,Cheng, Jiang
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p. 5336 - 5338
(2008/12/22)
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- Studies on antiplatelet agents from natural safrole. II. Synthesis and pharmacological properties of novel functionalized oxime O-benzylether derivatives
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In an ongoing research program aiming at the synthesis and pharmacological evaluation of new possible prototype candidates exploring the molecular hybridation and bioisosterism principles for molecular designing, we describe in this paper the design and synthesis of a series of new functionalized oxime O-benzylethers (4a-b) and (14a-b) as antiplatelet agents based on the inhibition of arachidonic acid (AA) cascade enzymes. For the synthesis of these new bioactive derivatives we used safrole (5), a Brazilian abundant natural product, as starting material. The platelet anti-aggregating evaluation of these oxime O-benzylether compounds (4a-b) and (14a-b) in model induced by ADP, collagen and AA, has permitted to evidence an antithrombotic profile to these new derivatives, being the most active the derivative methyl [[3,4-methylenedioxyphenyl]methylene]amino]oxy]-4-methylenephenylacetic acid (14a). Copyright (C) 1999 Elsevier Science B.V.
- De A. Reis, Andre L.,Ormelli, Claudia B.,Miranda, Ana L.P.,Fraga, Carlos A.M.,Barreiro, Eliezer J.
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