- Room temperature Z-selective hydrogenation of alkynes by hemilabile and non-innocent (NNN)Co(ii) catalysts
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Hemilabile and phosphine-free quinolinyl-based NNN-type pincer and non-pincer cobalt complexes were developed for the room temperature catalytic transfer semi-hydrogenation of alkynes to Z-alkenes. Treatment of the quinolinyl-amine ligand, [C9H6N(NH)CH2CH2NEt2] (QNNNCH2NEt2)-H with CoX2 afforded the pincer complexes κ3-(QNNNCH2NEt2)CoX2 (X = Cl, Br), whereas, the quinolinyl-amide ligand, [C9H6N(NH)C(O)CH2NEt2] (QNNNC(O)NEt2)-H gave chelate anionic complexes κ2-(QNN)CoX2(NC(O)HNEt2) (X = Cl, Br). The well-defined anionic non-pincer cobalt complexes efficiently catalyzed the semi-hydrogenation of diverse alkynes to deliver highly chemoselective and stereodivergent Z-alkenes at room temperature. This hydrogenation exhibited broad substrate scope with the tolerance of sensitive functional groups, such as -Cl, -Br, -I, -OH, -NH2, -COOMe, and pyridinyl, employing a stable and user-friendly ammonia borane hydrogen source.
- Gonnade, Rajesh G.,Gouda, Chandrakant,Punji, Benudhar,Sharma, Dipesh M.
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p. 1843 - 1849
(2022/04/07)
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- "bulky-Yet-Flexible" α-Diimine Palladium-Catalyzed Reductive Heck Cross-Coupling: Highly Anti-Markovnikov-Selective Hydroarylation of Alkene in Air
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To pursue a highly regioselective and efficient reductive Heck reaction, a series of moisture-and air-stable α-diimine palladium precatalysts were rationally designed, readily synthesized, and fully characterized. The relationship between the structures of the palladium complexes and the catalytic properties was investigated. It was revealed that the"bulky-yet-flexible"palladium complexes allowed highly anti-Markovnikov-selective hydroarylation of alkenes with (hetero)aryl bromides under aerobic conditions. Further synthetic application of the present protocol could provide rapid and straightforward access to functional and biologically active molecules.
- Yang, Xu-Wen,Li, Dong-Hui,Song, A-Xiang,Liu, Feng-Shou
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p. 11750 - 11765
(2020/10/23)
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- Deaminative Reductive Cross-Electrophile Couplings of Alkylpyridinium Salts and Aryl Bromides
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A nickel-catalyzed reductive cross-coupling of alkylpyridinium salts and aryl bromides has been developed using Mn as the reductant. Both primary and secondary alkylpyridinium salts can be used, and high functional group and heterocycle tolerance is observed, including for protic groups. Mechanistic studies indicate the formation of an alkyl radical, and controlling its fate was key to the success of this reaction.
- Liao, Jennie,Basch, Corey H.,Hoerrner, Megan E.,Talley, Michael R.,Boscoe, Brian P.,Tucker, Joseph W.,Garnsey, Michelle R.,Watson, Mary P.
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supporting information
p. 2941 - 2946
(2019/04/30)
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- One-Pot Electrochemical Nickel-Catalyzed Decarboxylative Sp2-Sp3 Cross-Coupling
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A one-pot electrochemical nickel-catalyzed decarboxylative sp2-sp3 cross-coupling reaction has been developed using redox-active esters prepared in situ from alkyl carboxylates and N-hydroxyphthalimide tetramethyluronium hexafluorophosphate (PITU). This undivided cell one-pot method enables C-C bond formation using inexpensive, benchtop-stable reagents with isolated yields up to 95% with good functional group tolerance, which includes nitrile, ketone, ester, alkene and selectivity over other aromatic halogens.
- Koyanagi, Takaoki,Herath, Ananda,Chong, Ashley,Ratnikov, Maxim,Valiere, Andrew,Chang, Jim,Molteni, Valentina,Loren, Jon
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supporting information
p. 816 - 820
(2019/01/30)
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- Copper-Catalyzed Radical Reductive Arylation of Styrenes with Aryl Iodides Mediated by Zinc in Water
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A copper/aniline catalyst system enables the radical arylation of styrenes using aryl iodides mediated by zinc in water. This transformation provides an efficient synthetic methodology for the convenient synthesis of diarylethane.
- Zhou, Feng,Hu, Xiaoyun,Zhang, Wanying,Li, Chao-Jun
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p. 7416 - 7422
(2018/05/14)
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- Nickel(0)-Catalyzed Hydroarylation of Styrenes and 1,3-Dienes with Organoboron Compounds
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A Ni-catalyzed hydroarylation of styrenes and 1,3-dienes with organoboron compounds has been developed. The reaction offers a highly selective approach to diarylalkanes and allylarenes under redox-neutral conditions. In this hydroarylation reaction, a new strategy that uses the proton of methanol to generate the active catalyst species Ni?H was developed. The Ni-catalyzed hydroarylation, combined with a Ir-catalyzed C?H borylation, affords a very efficient and straightforward access to a retinoic acid receptor agonist.
- Xiao, Li-Jun,Cheng, Lei,Feng, Wei-Min,Li, Mao-Lin,Xie, Jian-Hua,Zhou, Qi-Lin
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supporting information
p. 461 - 464
(2018/02/21)
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- Efficient phosphine-mediated formal C(sp3)-C(sp3) coupling reactions of alkyl halides in batch and flow
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The construction of C(sp3)-C(sp3) bond is an essential chemical transformation in synthetic chemistry due to its abundance in organic scaffolds. Here we demonstrate a valuable adaptation of the Wittig-type chemical procedure to efficiently facilitate C(sp3)-C(sp3) bond formation utilizing a range of alkyl building blocks. Additionally the method is amenable with flow synthesis to afford coupled products in good to excellent yields without laborious purification process.
- Tran,Hock,Gordon,Koenigs,Nguyen
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supporting information
p. 4950 - 4953
(2017/07/11)
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- Copper(i)-catalysed transfer hydrogenations with ammonia borane
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Highly Z-selective alkyne transfer semihydrogenations and conjugate transfer hydrogenations of enoates can be effected by employing a readily available and air-stable copper(i)/N-heterocyclic carbene (NHC) complex, [IPrCuOH]. As an easy to handle and potentially recyclable H2 source, ammonia borane (H3NBH3) is used.
- Korytiaková, Eva,Thiel, Niklas O.,Pape, Felix,Teichert, Johannes F.
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p. 732 - 735
(2017/01/13)
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- Reduction of diphenylacetylene using Al powder in the presence of noble metal catalysts in water
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Diphenylacetylenes can be reduced to the corresponding diphenylethanes (2) in water in excellent yield using Al powder and Pd/C at 60?°C for 3?h in a sealed tube. In addition, the complete reduction of both aromatic rings required 80?°C for 15?h with Al powder in the presence of Pt/C. However, the nature of hydrogenated product formed was found to be strongly influenced by the reaction temperature, time, volume of water and the amount of catalyst being employed.
- Rayhan, Ummey,Kowser, Zannatul,Redshaw, Carl,Yamato, Takehiko
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supporting information
p. 6943 - 6947
(2016/10/14)
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- Iron/tetramethylethylenediamine-catalyzed ambient-temperature coupling of alkyl grignard reagents and aryl chlorides
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Tetramethylethylenediamine (TMEDA) acts as cheap and readily removed ligand in the iron-catalyzed coupling of alkyl Grignard reagents and activated aryl chlorides. The use of TMEDA allows for low ligand and iron catalyst loading as well as an increased reaction concentration and an ambient reaction temperature on a mole scale.
- Rushworth, Philip J.,Hulcoop, David G.,Fox, David J.
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p. 9517 - 9521
(2013/10/08)
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- Nickel-mediated inter- and intramolecular reductive cross-coupling of unactivated alkyl bromides and aryl iodides at room temperature
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A nickel-mediated intermolecular reductive cross-coupling reaction of unactivated alkyl bromides and aryl iodides at room temperature has been developed and successfully extended to less explored intramolecular versions and tandem cyclization-intermolecular cross-coupling. Highly stereoselective (or stereospecific) synthesis of linear-fused perhydrofuro[2,3-b]furan (pyran) and spiroketal skeletons allows rapid access to these useful building blocks, which would be potentially valuable in the synthesis of relevant natural products. A rational explanation for the formation of contiguous stereogenic centers is given. Copyright
- Yan, Chang-Song,Peng, Yu,Xu, Xiao-Bo,Wang, Ya-Wen
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supporting information; experimental part
p. 6039 - 6048
(2012/06/18)
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- 1,2-Diarylethanols by alternative regioselective reductive ring-opening of 2,3-diaryloxiranes
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Non-symmetrical £rans-2,3-diaryloxiranes have been regioselectively opened by catalytic hydrogenation over Pd/C, NaBH4/Pd and [Cp 2TiCl]/H2O. Although in the catalytic hydrogenation reactions the epoxides were mainly opened at the β-carbon with respect to the substituted aryl ring in all cases, with the [Cp2TiCl]/H 2O system the regioselectivity was affected by the electronic properties of the aryl residues, the epoxides being opened on the carbon bearing the most electron-releasing or the least electron-withdrawing group. With the NaBH4/Pd system different regioisomers were obtained depending on the substituents. Starting from enantioenriched epoxides, no loss of optical purity was observed in the alcohols formed.
- Blasio, Nadia Di,Lopardo, Maria Teresa,Lupattelli, Paolo
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scheme or table
p. 938 - 944
(2009/07/19)
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- Cross-coupling reactions of primary alkylboronic acids with aryl triflates and aryl halides
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The cross-coupling reactions of primary alkylboronic acids with aryl triflates and aryl halides has been successfully achieved using PdCl2(dppf)·CH2Cl2 in the presence of potassium carbonate to provide the corresponding Su
- Molander, Gary A.,Yun, Chang-Soo
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p. 1465 - 1470
(2007/10/03)
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