- Modular approach for synthesis of vicinal diamines containing axial chiral 1,1′-binaphthyl from 1,2-diaminoethane by Pd-catalyzed n-arylation reactions
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A very convenient and efficient modular approach for the synthesis of vicinal diamines containing axial chiral 1,1′-binaphthyl from 1,2-diaminoethane by Pd-catalyzed N-arylation reactions has been developed. The resulting chiral diamines could be easily c
- Zhu, Shifa,Wang, Chao,Chen, Lijuan,Liang, Renxiao,Yu, Yingfeng,Jiang, Huanfeng
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- Phosphine ligand 2 - alkyl - indole skeleton as well as preparation method and application thereof
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The invention discloses a phosphine ligand 2 - alkyl - indole skeleton and a preparation method and application thereof, wherein the structural formula of the phosphine ligand 2 - alkyl - indole skeleton is shown I. , Wherein R. 1 . R2/su
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Paragraph 0131; 0144-0150; 0153-0154; 0169
(2021/09/21)
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- General Chemoselective Suzuki-Miyaura Coupling of Polyhalogenated Aryl Triflates Enabled by an Alkyl-Heteroaryl-Based Phosphine Ligand
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This study describes a general chemoselective Suzuki-Miyaura coupling of polyhalogenated aryl triflates with the reactivity order of C-Cl > C-OTf using a Pd/L33 catalyst. The methine hydrogen and the steric hindrance offered by the alkyl bottom ring of L33 were found to be key factors in reactivity and chemoselectivity. With the Pd/ L33 catalyst, a wide range of polyhalogenated (hetero)aryl triflates, which were independent of the substrates and of the relative positioning of the competing reaction sites, coupled well with (hetero)aryl, alkenyl, and alkylboronic acids to obtain the corresponding products with good chemoselectivity and yields. The chemoselective reaction could easily be scaled up to the gram scale, and the use of parts per million levels of Pd catalyst (as low as 10 ppm Pd) was achieved.
- So, Chau Ming,Yuen, On Ying,Ng, Shan Shan,Chen, Zicong
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p. 7820 - 7827
(2021/07/01)
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- Transition-Metal-Free C-C, C-O, and C-N Cross-Couplings Enabled by Light
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Transition-metal-catalyzed cross-couplings to construct C-C, C-O, and C-N bonds have revolutionized chemical science. Despite great achievements, these metal catalysts also raise certain issues including their high cost, requirement of specialized ligands, sensitivity to air and moisture, and so-called "transition-metal-residue issue". Complementary strategy, which does not rely on the well-established oxidative addition, transmetalation, and reductive elimination mechanistic paradigm, would potentially eliminate all of these metal-related issues. Herein, we show that aryl triflates can be coupled with potassium aryl trifluoroborates, aliphatic alcohols, and nitriles without the assistance of metal catalysts empowered by photoenergy. Control experiments reveal that among all common aryl electrophiles only aryl triflates are competent in these couplings whereas aryl iodides and bromides cannot serve as the coupling partners. DFT calculation reveals that once converted to the aryl radical cation, aryl triflate would be more favorable to ipso substitution. Fluorescence spectroscopy and cyclic voltammetry investigations suggest that the interaction between excited acetone and aryl triflate is essential to these couplings. The results in this report are anticipated to provide new opportunities to perform cross-couplings.
- Liu, Wenbo,Li, Jianbin,Querard, Pierre,Li, Chao-Jun
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supporting information
p. 6755 - 6764
(2019/05/06)
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- Efficient cross-coupling of aryl/alkenyl triflates with acyclic secondary alkylboronic acids
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Aryl-secondary alkyl cross-coupling with aryl sulfonate esters as coupling partners remains a significant challenge. Efficient cross-coupling between aryl/alkenyl triflates and acyclic secondary alkylboronic acids is realized for the first time to provide a series of sterically congested acyclic secondary alkyl arenes/olefins in good to excellent yields. The employment of sterically bulky P,PO ligand L1/L2 is crucial for the high yields and selectivities. The method has enabled a concise and 4-step synthesis of a key intermediate of male contraceptive agent and PAF antagonist gossypol.
- Si, Tengda,Li, Bowen,Xiong, Wenrui,Xu, Bin,Tang, Wenjun
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supporting information
p. 9903 - 9909
(2017/12/12)
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- Selective arylation and vinylation at the α position of vinylarenes
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In intermolecular Heck reactions of styrene and vinylarenes, the aryl and vinyl groups routinely insert at the β position. However, selective insertion at the α position has been very rare. Herein, we provide a missing piece in the palette of Heck reaction, which gave >20:1 α selectivity. The key to our success is a new ferrocene 1,1′-bisphosphane (dnpf) that carries 1-naphthyl groups. Our mechanistic studies revealed that the high α selectivity is partly attributable to the steric effect of dnpf. The rigid and bulky 1-naphthyl groups of dnpf sterically disfavor β insertion. What the Heck! In intermolecular Heck reactions, insertion at the β position of aromatic olefins is very common, but reversal of the selectivity for selective α insertion has been a longstanding problem. A general method to couple aryl and vinyl triflates with aromatic olefins in >20:1 α selectivity is presented. The key to this successful approach is a new ferrocene bisphosphane with naphthyl groups on the phosphorus atom (see scheme; OTf=triflate). Copyright
- Zou, Yinjun,Qin, Liena,Ren, Xinfeng,Lu, Yunpeng,Li, Yongxin,Zhou, Jianrong
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supporting information
p. 3504 - 3511
(2013/07/05)
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- Scope of direct arylation of fluorinated aromatics with aryl sulfonates
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The scope and limitations of direct arylation of fluorinated aromatics with aryl sulfonates was examined. Pd(OAc)2, in the presence of MePhos and KOAc in THF, efficiently catalyzed the direct arylation of fluoro aromatics with aryl triflates un
- Chang, Joyce Wei Wei,Chia, Eugene Yurong,Chai, Christina Li Lin,Seayad, Jayasree
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supporting information; experimental part
p. 2289 - 2299
(2012/04/10)
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- Intermolecular mizoroki-heck reaction of aliphatic olefins with high selectivity for substitution at the internal position
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New ligand for old reaction: The title reaction of aryltriflates with aliphatic olefins leads to substitution at the internal position with high selectivity. The ratio of the desired isomer (shown in the scheme) to the sum of all other isomers is generall
- Qin, Liena,Ren, Xinfeng,Lu, Yunpeng,Li, Yongxin,Zhou, Jianrong
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supporting information; experimental part
p. 5915 - 5919
(2012/07/30)
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