- Mechanochemical Solvent-Free Suzuki–Miyaura Cross-Coupling of Amides via Highly Chemoselective N?C Cleavage
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Although cross-coupling reactions of amides by selective N?C cleavage are one of the most powerful and burgeoning areas in organic synthesis due to the ubiquity of amide bonds, the development of mechanochemical, solid-state methods remains a major challe
- Ma, Yangmin,Shao, Lei,Szostak, Michal,Wang, Ruihong,Zhang, Jin,Zhang, Pei
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supporting information
(2022/01/04)
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- Mechanistic Insight into Copper-Mediated Trifluoromethylation of Aryl Halides: The Role of CuI
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The synthesis, characterization, and reactivity of key intermediates [Cu(CF3)(X)]-Q+ (X = CF3 or I, Q = PPh4) in copper-mediated trifluoromethylation of aryl halides were studied. Qualitative and quantitative studies showed [Cu(CF3)2]-Q+ and [Cu(CF3)(I)]-Q+ were not highly reactive. Instead, a much more reactive species, ligandless [CuCF3] or DMF-ligated species [(DMF)CuCF3], was generated in the presence of excess CuI. On the basis of these results, a general mechanistic map for CuI-promoted trifluoromethylation of aryl halides was proposed. Furthermore, on the basis of this mechanistic understanding, a HOAc-promoted protocol for trifluoromethylation of aryl halides with [Ph4P]+[Cu(CF3)2]- was developed.
- Jin, Yuxuan,Leng, Xuebing,Liu, He,Shen, Qilong,Wu, Jian
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supporting information
p. 14367 - 14378
(2021/09/13)
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- Poly(ethylene glycol) dimethyl ether mediated oxidative scission of aromatic olefins to carbonyl compounds by molecular oxygen
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A simple, and practical oxidative scission of aromatic olefins to carbonyl compounds using O2as the sole oxidant with poly(ethylene glycol) dimethyl ether as a benign solvent has been developed. A wide range of monosubstituted,gem-disubstituted, 1,2-disubstituted, trisubstituted and tetrasubstituted aromatic olefins was successfully converted into the corresponding aldehydes and ketones in excellent yields even with gram-scale reaction. Some control experiments were also conducted to support a possible reaction pathway.
- Yu, Tao,Guo, Mingqing,Wen, Simiaomiao,Zhao, Rongrong,Wang, Jinlong,Sun, Yanli,Liu, Qixing,Zhou, Haifeng
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p. 13848 - 13852
(2021/04/22)
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- Method for preparing aldehyde ketone compound through olefin oxidation
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The invention provides a method for preparing an aldehyde ketone compound by olefin oxidation, which relates to an olefin oxidative cracking reaction in which oxygen participates. The method comprises the following specific steps: in the presence of a solvent and an oxidant, carrying out oxidative cracking on an olefin raw material to obtain a corresponding aldehyde ketone product. Compared with the traditional method, the method does not need to add any catalyst or ligand, does not need to use high-pressure oxygen, has the advantages of simple and mild reaction conditions, environment friendliness, low cost, high atom economy and the like, is wide in substrate application range and high in yield, and has a wide application prospect in the aspects of synthesis of aldehyde ketone medical intermediates and chemical raw materials.
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Paragraph 0019
(2021/04/07)
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- Chiral electron-rich PNP ligand with a phospholane motif: Structural features and application in asymmetric hydrogenation
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Despite the remarkable reactivity that was achieved by a series of transition-metal catalysts with a PNP type ligand, the electron-rich chiral PNP ligands have still been rarely reported because of the difficulties in synthesis and the nature of air-sensitivity. Herein, we report a novel chiral PNP ligand (Heng-PNP) with both a rigid backbone and a bulky tert-butyl group on the phospholane motif. We successfully obtained its divalent iron complex. The chiral environment of its Ir(III) complex was also discussed with quadrant analysis. This tridentate ligand was applied in iridium-catalyzed asymmetric hydrogenation of challenging diaryl ketones: up to 98% ee and 500 TON are achieved. Computational study showed that the twist of conjugate aryl group in the substrate (induced by the special chiral pocket of Ir/Heng-PNP complex) leads to the energy difference in the enantiodetermining step.
- Wang, Heng,Zhang, Yao,Yang, Tilong,Guo, Xiaochong,Gong, Quan,Wen, Jialin,Zhang, Xumu
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p. 8796 - 8801
(2020/11/13)
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- Palladium-Catalyzed Ligand-Free Decarboxylative Coupling of α- Oxocarboxylic Acid with Aryl Diazonium Tetrafluoroborate: An Access to Unsymmetrical Diaryl Ketones
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Diaryl ketones are of much importance in organic synthesis as versatile intermediates and in industry for their useful properties. A mild and efficient palladium-catalyzed traditional ligand-free decarboxylative coupling of aryl α-keto carboxylic acid with aryl diazonium fluoroborate has been developed. A series of unsymmetrical diaryl ketones has been synthesized in moderate to good yields using this procedure. A radical pathway involving the acyl radical has been suggested.
- Panja, Subir,Maity, Pintu,Ranu, Brindaban C.
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p. 12609 - 12618
(2018/10/20)
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- Pd-NHC catalysed Carbonylative Suzuki coupling reaction and its application towards the synthesis of biologically active 3-aroylquinolin-4 (1H)-one and acridone scaffolds
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We have unfolded a convenient and mild protocol for the synthesis of diaryl ketones via Pd- NHC catalysed carbonylative Suzuki coupling reaction. Notably, this method offers advantages like no use of toxic CO gas, shorter reaction time, high yield, and broad substrate scope. Several sensitive functional groups (like-COMe, -COOMe, -F, -Cl, -Br, -NH2, -CN) are well tolerated in this reaction. In addition, we have also demonstrated a new efficient route for the synthesis of biologically active and pharmaceutically important 2-substituted 3-Aroylquinolin-4(1H)-ones and acridone scaffolds.
- Ghosh, Prasanjit,Ganguly, Bhaskar,Das, Sajal
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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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p. 6510 - 6513
(2017/12/26)
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- One-pot sandmeyer trifluoromethylation and trifluoromethylthiolation
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Practical one-pot procedures were developed for both Sandmeyer-type trifluoromethylations and trifluoromethylthiolations. Starting from broadly available (hetero)aromatic amines, various benzotrifluorides were synthesized in high yields via in situ diazotization and copper-mediated trifluoromethylation using the inexpensive Ruppert-Prakash trifluoromethylating reagent. In the presence of sodium thiocyanate as a sulfur source, aryl trifluoromethyl thioethers are exclusively formed.
- Bayarmagnai, Bilguun,Matheis, Christian,Risto, Eugen,Goossen, Lukas J.
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supporting information
p. 2343 - 2348
(2014/07/21)
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- Sandmeyer trifluoromethylation of arenediazonium tetrafluoroborates
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Copper capabilities: Diazonium salts are converted into the corresponding trifluoromethyl derivatives in the presence of a trifluoromethyl-copper complex generated in situ from CuSCN and the inexpensive, easy-to-use trifluoromethylating reagent Me3Si-CF3 (see scheme). This Sandmeyer-type reaction allows the straightforward synthesis of trifluoromethylated arenes and heteroarenes from the corresponding amines. Copyright
- Danoun, Grégory,Bayarmagnai, Bilguun,Grünberg, Matthias F.,Goo?en, Lukas J.
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p. 7972 - 7975
(2013/08/23)
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- Copper-promoted sandmeyer trifluoromethylation reaction
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A copper-promoted trifluoromethylation reaction of aromatic amines is described. This transformation proceeds smoothly under mild conditions and exhibits good tolerance of many synthetically relevant functional groups. It provides an alternative approach for the synthesis of trifluoromethylated arenes and heteroarenes. It also constitutes a new example of the Sandmeyer reaction.
- Dai, Jian-Jun,Fang, Chi,Xiao, Bin,Yi, Jun,Xu, Jun,Liu, Zhao-Jing,Lu, Xi,Liu, Lei,Fu, Yao
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supporting information
p. 8436 - 8439
(2013/07/19)
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- Rhodium-catalyzed aerobic coupling between aldehydes and arenesulfinic acid salts: A novel synthesis of aryl ketones
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A novel rhodium-catalyzed desulfinative coupling between aldehydes and arenesulfinic acid sodium salts was developed, generating a new protocol for the synthesis of aryl ketones. Most importantly, the coupling reaction uses molecular oxygen (O2) as the oxidant and finally releases sodium hydrogen sulfate (NaHSO4) from the reaction system; furthermore, this reaction occurs without the need for any additives. Copyright
- Rao, Honghua,Yang, Luo,Shuai, Qi,Li, Chao-Jun
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supporting information; experimental part
p. 1701 - 1706
(2011/09/14)
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- Protolytic defluorination of trifluoromethyl-substituted arenes
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A series of trifluoromethyl-substituted arenes were studied in their reactions with Bronsted superacids. The products from these reactions suggest the formation of reactive electrophiles, such as carbocations, acylium cations or equivalent electrophilic species. As such, Friedel-Crafts-type reactions occur between these species and arene nucleophiles. NMR studies were done, and the results suggest the formation of an acyl group from the trifluoromethyl groups in the superacid.
- Kethe, Anila,Tracy, Adam F.,Klumpp, Douglas A.
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experimental part
p. 4545 - 4549
(2011/07/29)
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- Easy-to-execute carbonylative arylation of aryl halides using molybdenum hexacarbonyl: Efficient synthesis of unsymmetrical diaryl ketones
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A versatile procedure for the synthesis of unsymmetrical diaryl ketones through a palladium-catalyzed carbonylative arylation of iodoarenes through easy-to-handle molybdenum hexacarbonyl as a condensed source of carbon monoxide is described. This method provides an efficient route to a wide variety of substituted diaryl ketones without direct use of high-pressure carbon monoxide. Copyright
- Jafarpour, Farnaz,Rashidi-Ranjbar, Parviz.,Kashani, Asieh Otaredi
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experimental part
p. 2128 - 2132
(2011/05/09)
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- New preparation and reactions of arylaluminum reagents using Barbier conditions
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The reaction of various aryl bromides with magnesium turnings, LiCl and R2AlCl (R = Et, i-Bu) provides at room temperature arylaluminum reagents in high yields. These organometallic species undergo readily 1,4-additions, acylations, allylations, and Pd-catalyzed cross-couplings with various aryl iodides and bromides. Georg Thieme Verlag Stuttgart.
- Gao, Hongjun,Knochel, Paul
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experimental part
p. 1321 - 1325
(2009/12/01)
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- Palladium-catalyzed arylation of α,α-disubstituted arylmethanols via cleavage of a C-C or a C-H bond to give biaryls
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The palladium-catalyzed arylation of α,α-disubstituted arylmethanols with aryl halides proceeds not only via C-H bond cleavage at the ortho-position, but also via cleavage of the sp2-sp3 C-C bond with the liberation of ketones (β-carbon elimination) to give the corresponding biaryls. Both reactions appear to occur through common arylpalladium(II) alcoholate intermediates. The results of systematic studies with respect to which C-C or C-H bond is preferentially cleaved in the arylation are reported. Among the important findings is the selective elimination of ortho-substituted aryl groups even from aryl(diphenyl)methanols due to steric reasons. Thus, various biaryls having ortho-substituents can be produced efficiently by treatment of the corresponding aryl(diphenyl or dimethyl)methanols with aryl bromides and chlorides.
- Terao, Yoshito,Wakui, Hiroyuki,Nomoto, Michiyo,Satoh, Tetsuya,Miura, Masahiro,Nomura, Masakatsu
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p. 5236 - 5243
(2007/10/03)
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- A Convenient Preparation of Functionalized Arylzinc Compounds by the Reaction of Zinc/Silver-Graphite with Aryl Iodides.
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Aryl- and hetero-aryl iodides react under very mild conditions (THF, 25 deg C) with a Zn(Ag) couple deposited on graphite leading to the corresponding zinc reagents in excellent yields.In the presence of CuCN*2LiCl or catalytic amounts of Pd(O), these unsaturated zinc species can be acylated, allylated or coupled with iodoalkenes.
- Fuerstner, Alois,Singer, Robert,Knochel, Paul
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p. 1047 - 1050
(2007/10/02)
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- Determination of the Enantiomeric Excesses of Chiral Acids by 19F NMR Studies of their Esters deriving from (R)-(+)-2-(Trifluoromethyl)benzhydrol
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15-Chiral acids were esterified with optically pure (R)-(+)-2-(trifluoromethyl)benzhydrol (R)-(+)-1, a readily available reagent.With respect to the carboxy group, the stereogenic centre is in the β-position in the case of the acids 5a-10a and 12a-16a, and in the α position in the case of the acids 17a-20a.The diastereomeric excesses of the corresponding esters 5b-10b and 12b-20b, respectively, were easily determined by means of 19F NMR.These d.e. values were in very good agreement with the e.e. values of the corresponding acids when the latter were known compounds.
- Brown, Eric,Chevalier, Christelle,Huet, Francois,Grumelec, Christelle Le,Leze, Antoine,Touet, Joel
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p. 1191 - 1194
(2007/10/02)
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- THE TRIFLUOROMETHYLATION OF CHLOROAROMATICS USING THE COPPER-CF2Br2-DIALKYLAMIDE REACTION SYSTEM
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The in situ generation of CuCF3 from the reaction of copper, dibromodifluoromethane and either N,N-dimethylformamide or N,N-dimethylacetamide (Burton's reagent) has been used for the direct substitution of chlorine by CF3 in a number of aromatic substrates.Particular attention has been paid to the effects of ring substituents on the efficiency of reaction.
- Clark, James H.,Denness, James E.,McClinton, Martin A.,Wynd, Andrew J.
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p. 411 - 426
(2007/10/02)
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- Process for dimerization, arylation and trifluoromethylation of aromatic and heterocyclic compounds
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A decarboxylation process for coupling aromatic compounds wherein cyclic hydrocarbons and heterocyclic compounds having at least one labile ring hydrogen are reacted with the mono silver salts of aromatic carboxylic acids, or mono silver salts of unsaturated compounds such as α,β-ethylenically unsaturated acid compounds, or silver trifluoroacetate, or the mono silver salts are reacted with themselves, by heating to temperatures of 100° to 500° C. at pressures of 0.1 to 10 atmospheres, or by irradiating the reactants with ultraviolet light of 200 to 400 nanometers at temperatures of -30° to 150° C. The resulting dimers, trimers, polysubstituted polyphenyls, polyheterocyclics and trifluoromethylated aromatics are useful as heat transfer media, as intermediates for high molecular weight polymers, pesticides and petroleum additives, and as scintillation counters.
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