- A Nickel(II)-Mediated Thiocarbonylation Strategy for Carbon Isotope Labeling of Aliphatic Carboxamides
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A series of pharmaceutically relevant small molecules and biopharmaceuticals bearing aliphatic carboxamides have been successfully labeled with carbon-13. Key to the success of this novel carbon isotope labeling technique is the observation that 13C-labeled NiII-acyl complexes, formed from a 13CO insertion step with NiII-alkyl intermediates, rapidly react in less than one minute with 2,2’-dipyridyl disulfide to quantitatively form the corresponding 2-pyridyl thioesters. Either the use of 13C-SilaCOgen or 13C-COgen allows for the stoichiometric addition of isotopically labeled carbon monoxide. Subsequent one-pot acylation of a series of structurally diverse amines provides the desired 13C-labeled carboxamides in good yields. A single electron transfer pathway is proposed between the NiII-acyl complexes and the disulfide providing a reactive NiIII-acyl sulfide intermediate, which rapidly undergoes reductive elimination to the desired thioester. By further optimization of the reaction parameters, reaction times down to only 11 min were identified, opening up the possibility of exploring this chemistry for carbon-11 isotope labeling. Finally, this isotope labeling strategy could be adapted to the synthesis of 13C-labeled liraglutide and insulin degludec, representing two antidiabetic drugs.
- Pedersen, Simon S.,Donslund, Aske S.,Mikkelsen, Jesper H.,Bakholm, Oskar S.,Papp, Florian,Jensen, Kim B.,Gustafsson, Magnus B. F.,Skrydstrup, Troels
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supporting information
p. 7114 - 7123
(2021/03/03)
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- Metal-Free Formal Oxidative C?C Coupling by In Situ Generation of an Enolonium Species
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Much contemporary organic synthesis relies on transformations that are driven by the intrinsic, so-called “natural”, polarity of chemical bonds and reactive centers. The design of unconventionally polarized synthons is a highly desirable strategy, as it generally enables unprecedented retrosynthetic disconnections for the synthesis of complex substances. Whereas the umpolung of carbonyl centers is a well-known strategy, polarity reversal at the α-position of a carbonyl group is much rarer. Herein, we report the design of a novel electrophilic enolonium species and its application in efficient and chemoselective, metal-free oxidative C?C coupling.
- Kaiser, Daniel,de la Torre, Aurélien,Shaaban, Saad,Maulide, Nuno
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supporting information
p. 5921 - 5925
(2017/05/12)
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- Copper-catalyzed one-pot oxidative amidation of alcohol to amide via C-H activation
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A one-pot oxidative amidation of both aliphatic and aromatic alcohols with N-chloramines, prepared in situ from many types of primary and secondary amines, was developed. This cross-coupling reaction integrates alcohol oxidation and amide bond formation, which are usually accomplished separately, into a single operation. And it was green, simple and convenient, which has a wide substrate scope and makes use of cheap, abundant, and easily available reagents. The practical value of this method is highlighted through the synthesis of a high-profile pharmaceutical agent, acetylprocainamide.
- Gu, Jiajia,Fang, Zheng,Yang, Yuhang,Yang, Zhao,Wan, Li,Li, Xin,Wei, Ping,Guo, Kai
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p. 89413 - 89416
(2016/10/03)
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- Chemo- and Stereoselective Transition-Metal-Free Amination of Amides with Azides
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The synthesis of α-amino carbonyl/carboxyl compounds is a contemporary challenge in organic synthesis. Herein, we present a stereoselective α-amination of amides employing simple azides that proceeds under mild conditions with release of nitrogen gas. The
- Tona, Veronica,De La Torre, Aurélien,Padmanaban, Mohan,Ruider, Stefan,González, Leticia,Maulide, Nuno
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supporting information
p. 8348 - 8351
(2016/07/26)
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- Selective Conjugate Reduction of α,β-Unsaturated Esters and Amides via SmI2-Promoted Electron Transfer Process
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α,β-Unsaturated esters and amides were rapidely and selectively reduced to the coresponding saturated ones under mild conditions without affecting coexisting isolated double or triple bonds by using the reduction system, SmI2-N,N-dimethylacetamide (DMA)-proton source.
- Inanaga, Junji,Sakai, Shino,Handa, Yuichi,Yamaguchi, Masaru,Yokoyama, Yasuo
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p. 2117 - 2118
(2007/10/02)
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- Conjugate Reduction of α,β-Unsaturated Carbonyl Compounds by Catecholborane
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α,β-Unsaturated ketones which can readily adopt an s-cis conformation undergo conjugate reduction by catecholborane at room temperature. α,β-Unsaturated imides, esters, and amides are unreactive under the same conditions.However, catalytic quantities of Rh(PPh3)3Cl greatly accelerate the 1,4-addition process, effecting conjugate reduction of these substrates by catecholborane at -20 deg C.The resulting boron enolates may be reacted with electrophiles to provide functionalized products.
- Evans, David A.,Fu, Gregory C.
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p. 5678 - 5680
(2007/10/02)
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