- Continuous Flow Acylation of (Hetero)aryllithiums with Polyfunctional N,N-Dimethylamides and Tetramethylurea in Toluene
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The continuous flow reaction of various aryl or heteroaryl bromides in toluene in the presence of THF (1.0 equiv) with sec-BuLi (1.1 equiv) provided at 25 °C within 40 sec the corresponding aryllithiums which were acylated with various functionalized N,N-
- Djukanovic, Dimitrije,Filipponi, Paolo,Heinz, Benjamin,Knochel, Paul,Mandrelli, Francesca,Martin, Benjamin,Mostarda, Serena
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supporting information
p. 13977 - 13981
(2021/09/13)
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- CoI-Catalyzed Barbier Reactions of Aromatic Halides with Aromatic Aldehydes and Imines
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The reductive Barbier coupling of aromatic halides and electrophiles has been achieved using a CoBr2/1,10-phenanthroline catalytic system and over stoichiometric amounts of zinc. The reaction displayed a broad scope of substrates, including (hetero)aryl chlorides as pro-nucleophiles and aldehydes or imines as electrophiles, leading to diarylmethanols and diarylmethylamines in moderate to excellent yields, respectively.
- Presset, Marc,Paul, Jér?me,Cherif, Ghania Nait,Ratnam, Nisanthan,Laloi, Nicolas,Léonel, Eric,Gosmini, Corinne,Le Gall, Erwan
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supporting information
p. 4491 - 4495
(2019/02/27)
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- Scandium as a pre-catalyst for the deoxygenative allylation of benzylic alcohols
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Scandium triflate is an effective pre-catalyst for the deoxygenative allylation of benzylic alcohols with a narrow substrate window. The reaction is shown to proceed through a "hidden Br?nsted acid" mechanism. The reaction is efficient provided that the aryl group is neither too electron rich nor too electron poor. It is shown that this allows useful selectivity. The reaction also works for benzyhydryl alcohols with broader scope. The reaction may also be catalysed by Nafion.
- ?oli?, Ivan,Seankongsuk, Pattarakiat,Loh, Joanna Kejun,Vilaivan, Tirayut,Bates, Roderick W.
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supporting information
p. 119 - 123
(2017/12/27)
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- Recyclable and reusable Pd(OAc)2/P(1-Nap)3/[bmim][PF6]/H2O system for the addition of arylboronic acids to aldehydes
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A stable and efficient Pd(OAc)2/P(1-Nap)3[tri(1-naphthyl)phosphine] catalytic system for the addition of arylboronic acids to aldehydes has been developed. In the presence of Pd(OAc)2 and P(1-Nap)3, the addition reaction of arylboronic acids with aldehydes was carried out smoothly at 65 °C to give a variety of carbinol derivatives in good to excellent yields using a mixture of [bmim][PF6] and water as the solvent. The isolation of the products was readily performed by the extraction with diethyl ether, and the Pd(OAc)2/P(1-Nap)3/[bmim][PF6]/H2O system could be easily recycled and reused six times without significant loss of catalytic activity. Our system not only avoids the use of easily volatile THF or toluene as solvent but also solves the basic problem of palladium catalyst and these phosphine ligand reuse.
- Zhao, Hong,Cheng, Mingzhu,Zhang, Tinli,Cai, Mingzhong
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- Sodium bisulfite: An efficient catalyst for ether formation via dehydration of aromatic/aliphatic alcohol
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Straightforward etherification of benzyl alcohols (1) via intermolecular dehydration can be efficiently catalyzed by sodium bisulfite under solvent-free conditions. In the presence of 0.3 mol% or 0.6 mol% amount of sodium bisulfite, symmetric and unsymmetric ethers are prepared from the corresponding alcohols in high yields (up to 95%). Etherification of benzhydryl alcohols is also discussed. Copyright
- Wang, Hui,Zhu, Xingfei,Lu, Yangning,Li, Yue,Gao, Xiang
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experimental part
p. 1180 - 1184
(2012/04/23)
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- Rh(1,3-bis(2,4,6-trimethylphenyl)-3,4,5,6-tetrahydropyrimidin-2-ylidene) (COD) tetrafluoroborate, an unsymmetrical Rh-homoazallylcarbene: Synthesis, X-ray structure and reactivity in carbonyl arylation and hydrosilylation reactions
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The synthesis of novel Rh(1,3-bis(2,4,6-trimethylphenyl)-3,4,5,6- tetrahydropyrimidin-2-ylidene)(COD) tetrafluoroborate (1, COD = η4-1,5-cyclooctadiene) is described. The N-heterocyclic carbene acts as a bidentate ligand with the carbene coordinating to the Rh(I) center and an arene group acting as a homoazallyl ligand. 1 was used in various carbonyl arylation and hydrosilylation reactions allowing the formation of the desired products with unprecedented selectivity and efficiency. Thus, turn-over numbers (TONs) up to 2000 were achieved.
- Imlinger, Nicolas,Wurst, Klaus,Buchmeiser, Michael R.
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p. 4433 - 4440
(2007/10/03)
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- Arylation of carbonyl compounds catalyzed by rhodium and iridium 1,3-R 2-tetrahydropyrimidin-2-ylidenes: Structure-reactivity correlations
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Six different well-defined rhodium and iridium N-heterocyclic carbene complexes, i.e., RhCl-(1,3-dimesityltetrahydropyrimidin-2-ylidene)(COD) (1), RhBr(1,3-dimesityltetrahydropyrimidin-2-ylidene)-(COD) (2), RhCl[1,3-di(2- propyl)tetrahydropyrimidin-2-ylidene](COD) (3), IrCl(1,3- dimesityltetrahydropyrimidin-2-ylidene)(COD) (4), Rh(CF3COO) (1,3-dimesityltetrahydropyrimidin-2-ylidene)(COD) (5), and IrBr[1,3-di(2-propyl) tetrahydropyrimidin-2-ylidene](COD) (6) (COD = 1,5-cyclooctadiene, mesityl = 2,4,6-trimethylphenyl) have been used as catalysts for the arylation of aldehydes and α,β-unsaturated ketones using different arylboronic acids. Compounds 1-4 and 6 were prepared by reaction of [RhCl(COD)]2 and [IrCl(COD)]2, respectively, with a base and the corresponding 1,3-R2-tetrahydropyrimidinium salt. Compound 5 was prepared by reaction of 1.0 equivalents of CF3COOAg with 1. The use of an excess of CF3COOAg resulted in the replacement of Rh(I) by Ag(I) and yielded Ag(1,3-dimesityltetrahydropyrimidin-2-ylidene)+Rh 2(CF3COO)3(COD)- (8). Compounds 4 and 8 were characterized by X-ray analysis. The activity of the rhodium complexes increased in the order 5 > 3 > 1 > 2, indicating the necessity of strongly electron-withdrawing groups at the metal centers, thus increasing their nucleophilicity. In due consequence, the softer iridium complexes 4 and 6 exhibited significantly reduced catalytic activity albeit with enhanced selectivity. The syntheses of the metal complexes as well as a detailed study on their reactivity in the arylation of carbonyl compounds using equimolar amounts of arylboronic acid and carbonyl compound in the presence of 0.08-1 mol % catalyst are presented.
- Imlinger, Nicolas,Mayr, Monika,Wang, Dongren,Wurst, Klaus,Buchmeiser, Michael R.
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p. 1836 - 1843
(2007/10/03)
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- Antiimplantation Agents: Part IV - 4-Benzhydrylidenepiperidines and Tetrahydropyran Analogues of F 6066
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Several α-(4-pyridyl)enzhydrols (8) have been synthesised by Grignard reaction on 4-aroylpyridines (6) or ethyl isonicotinate (7).The quaternary salts 9 of 8 are reduced catalytically to α-(4-piperidyl)benzhydrols (10) which undergo dehydration to benzhyd
- Nagarajan, K.,Talwalker, P. K.,Shah, R. K.,Shenoy, S. J.
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p. 112 - 118
(2007/10/02)
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