- Inherent vs Apparent Chemoselectivity in the Kumada-Corriu Cross-Coupling Reaction
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The Kumada-Corriu reaction is a powerful tool for C-C bond formation, but is seldom utilized due to perceived chemoselectivity issues. Herein, we demonstrate that high-yielding couplings can occur in the presence of many electrophilic and heterocyclic functional groups. Our strategy is mechanically based, matching oxidative addition rates with the rate of syringe pump addition of the Grignard reagent. The mechanistic reason for the effectiveness of this strategy is uncovered by continuous-infusion ESI-MS studies.
- Hua, Xiye,Masson-Makdissi, Jeanne,Sullivan, Ryan J.,Newman, Stephen G.
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supporting information
p. 5312 - 5315
(2016/11/02)
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- Room-temperature Suzuki-Miyaura coupling of heteroaryl chlorides and tosylates
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Suzuki-Miyaura coupling of heteroaryls is an important method for the preparation of compound libraries for medicinal chemistry and materials research. Although many catalysts have been developed, none of them have been generally applicable to the coupling reactions of heteroaryl chlorides and tosylates at room temperature. We discovered that a catalyst combination of Pd(OAc)2 and XPhos (2-dicyclohexylphosphanyl-2',4',6'- triisopropylbiphenyl) could efficiently catalyze these couplings. Besides the choice of catalyst, the use of hydroxide bases in an aqueous alcoholic solvent was essential for fast couplings. These conditions promoted fast release of active catalyst (XPhos)Pd0, and accelerated the transmetalation in the catalytic cycle. Most of the major families of heteroaryl chlorides (31 examples) and tosylates (17 examples) reached full conversion within minutes to hours at room temperature. The method could be easily scaled up for gram-scale synthesis. Furthermore, we examined the relative reactivity of coupling partners in whole reactions. Electron-rich heteroaryl chlorides and tosylates reacted more slowly than electron-deficient ones, in the order of indole, pyrrole furan, thiophene > pyridine. Similarly, electron-deficient arylboronic acids were less reactive than electron-neutral and electron-rich ones. The reactivity trends from this study can help to choose appropriate coupling partners for Suzuki reactions.
- Yang, Junfeng,Liu, Sijia,Zheng, Jian-Feng,Zhou, Jianrong
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supporting information
p. 6248 - 6259,12
(2020/09/16)
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- Creating an antibacterial with in vivo efficacy: Synthesis and characterization of potent inhibitors of the bacterial cell division protein FTSZ with improved pharmaceutical properties
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3-Methoxybenzamide (1) is a weak inhibitor of the essential bacterial cell division protein FtsZ. Alkyl derivatives of 1 are potent antistaphylococcal compounds with suboptimal drug-like properties. Exploration of the structure-activity relationships of analogues of these inhibitors led to the identification of potent antistaphylococcal compounds with improved pharmaceutical properties.
- Haydon, David J.,Bennett, James M.,Brown, David,Collins, Ian,Galbraith, Greta,Lancett, Paul,MacDonald, Rebecca,Stokes, Neil R.,Chauhan, Pramod K.,Sutariya, Jignesh K.,Nayal, Narendra,Srivastava, Anil,Beanland, Joy,Hall, Robin,Henstock, Vincent,Noula, Caterina,Rockley, Chris,Czaplewski, Lloyd
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supporting information; experimental part
p. 3927 - 3936
(2010/09/04)
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- Discovery of heterobicyclic templates for novel metabotropic glutamate receptor subtype 5 antagonists
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Investigation of a series of heterobicyclic compounds with essential pharmacophoric features of the metabotropic glutamate receptor 5 (mGluR5) antagonists MPEP and MTEP provided novel structural templates with sub-micromolar affinities at the mGluR5.
- Kulkarni, Santosh S.,Newman, Amy Hauck
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p. 2987 - 2991
(2008/02/07)
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- Cross-coupling of triallyl(aryl)silanes with aryl bromides and chlorides: An alternative convenient biaryl synthesis
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Cross-coupling of a diverse range of aryl bromides with triallyl(aryl)silanes is effective in the presence of PdCl2/PCy 3 and tetrabutylammonium fluoride (TBAF) in DMSO-H2O to give various biaryls in good yields. It is worthwhile to note that the all-carbon-substituted arylsilanes, stable towards moisture, acid, and base and easily accessible, serve as a highly practical alternative to their aryl(halo)silane counterparts. A catalyst system consisting of [η3-C3H5)PdCl]2 and 2-[2,4,6-(i-Pr)3C6Ha]-C6H4PCy 2 and use of TBAF· 3 H2O in THF-H2O are effective especially for the cross-coupling with aryl chlorides. Both of the catalyst systems tolerate a broad spectrum of common functional groups. The high efficiency of reactions is presumably due to the ready cleavage of the allyl groups upon treatment with TBAF·3 H2O and an appropriate amount of water. Diallyl(diphenyl)silane also cross-couples with various aryl bromides and chlorides in good yields, whereas allyl(triphenyl)silane gives the cross-coupled products in only moderate yields. Through sequential cross-coupling of bromochlorobenzenes with different arylsilanes, a range of unsymmetrical terphenyls are accessible in good overall yields.
- Sahoo, Akhila K.,Oda, Takuro,Nakao, Yoshiaki,Hiyama, Tamejiro
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p. 1715 - 1727
(2007/10/03)
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- Synthesis of 5- and 6-Substituted 2-Methylbenzothiazoles under Conditions of Metal Complex Catalysis
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Methods are proposed for preparation of 5- and 6-substituted 2-methylbenzothiazoles by reactions of organozinc and organotin compounds with 5- and 6-bromo-2-methylbenzothiazoles, catalyzed by palladium complexes. The reactions of organozinc compounds with 5(6)-bromo-2-methylbenzothiazoles occur in THF at 20°C in the presence of PdCl2(dppf), and those of organotin compounds are carried out in DMF, aqueous DMF, or water at 40-100°C in the presence of PdCl2, Pd(OAc)2, or PdCl2(PPh3)2.
- Bumagin,Nikitina,Beletskaya
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p. 1803 - 1811
(2007/10/03)
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