scholarly journals Anodic coupling of carboxylic acids to electron-rich double bonds: A surprising non-Kolbe pathway to lactones

2013 ◽  
Vol 9 ◽  
pp. 1630-1636 ◽  
Author(s):  
Robert J Perkins ◽  
Hai-Chao Xu ◽  
John M Campbell ◽  
Kevin D Moeller
Keyword(s):  
Carboxylic Acids ◽  
Radical Cation ◽  
Experimental Results ◽  
Double Bonds ◽  
Reaction Proceeds

Carboxylic acids have been electro-oxidatively coupled to electron-rich olefins to form lactones. Kolbe decarboxylation does not appear to be a significant competing pathway. Experimental results indicate that oxidation occurs at the olefin and that the reaction proceeds through a radical cation intermediate.

Copper-Catalyzed Decarboxylative N-Arylation of Indole-2-carboxylic Acids

Synthesis ◽  
2019 ◽  
Vol 51 (08) ◽  
pp. 1803-1808 ◽  
Author(s):  
Yan Zhang ◽  
Zhe-Yao Hu ◽  
Xin-Chang Li ◽  
Xun-Xiang Guo
Keyword(s):  
Carboxylic Acids ◽  
Functional Group ◽  
Aryl Halides ◽  
Synthetic Method ◽  
Alternative Route ◽  
Reaction Proceeds ◽  
High Yields

A novel decarboxylative N-arylation of indole-2-carboxylic acids with aryl halides is developed. The reaction proceeds efficiently in the presence of Cu2O as the catalyst to give the corresponding N-aryl indoles in high yields. This synthetic method shows good functional group tolerance and offers an alternative route to construct N-aryl indoles.

Photochemical nucleophile–olefin combination, aromatic substitution (photo-NOCAS) reaction. Part 6: methanol, nonconjugated dienes, and 1,4-dicyanobenzene

1994 ◽  
Vol 72 (2) ◽  
pp. 415-429 ◽  
Author(s):  
Donald R. Arnold ◽  
Kimberly A. McManus ◽  
Xinyao Du
Keyword(s):  
Electron Transfer ◽  
Double Bond ◽  
Radical Cation ◽  
Oxidation Potential ◽  
Aromatic Substitution ◽  
Double Bonds ◽  
Excited Singlet ◽  
Reaction Conditions ◽  
Methanol Solutions ◽  
Cyclic Adducts

Irradiation, through Pyrex, of an acetonitrile–methanol (3:1) solution of 1,4-dicyanobenzene (1) and 1,5-hexadiene (9) leads to formation of ortho and meta cyclic adducts (13–16) arising from the intermediate exciplex. There was no evidence for interaction between the two double bonds of this nonconjugated diene. The oxidation potential of 9 is high enough (> 3 V vs. sce) to preclude single electron transfer (SET); no photo-NOCAS products are formed. Similar irradiation of acetonitrile–methanol solutions of 1 and 2-methyl-1,5-hexadiene (10) does yield a photo-NOCAS product (17); reaction occurs only on the more heavily substituted double bond. The additional substitution on the double bond lowers the oxidation potential (2.70 V vs. sce) of this diene to the point where SET from 10 to the excited singlet state of 1 can occur. In this case, no cycloaddition products are formed; the exciplex is quenched by electron transfer. There was no evidence for interaction between the two double bonds of the initially formed radical cation 10+•, or between the terminal double bond and the β-alkoxyalkyl radical of the intermediate leading to the photo-NOCAS product. The photo-NOCAS product (19) was also formed when 2,5-dimethyl-1,5-hexadiene (11) was subjected to these reaction conditions. In this case, when biphenyl (4) was added as a codonor, in addition to the photo-NOCAS product, products (21cis and trans) resulting from cyclization of the initially formed acyclic radical cation 11+• to give the 1,4-dimethylcyclohexane-1,4-diyl radical cation were also observed. This 1,6-endo, endo cyclization of 11+• must be rapid enough to compete with reaction with methanol. There was no evidence for cyclization (neither 1,4-exo nor 1,5-endo) of the intermediate β-alkoxyalkyl radical. When the radical cation of 2,5-dimethyl-1,4-hexadiene (12+•) is generated under these reaction conditions, photo-NOCAS products 22 and 23 are formed at the more heavily substituted double bond, along with the conjugated tautomer 2,5-dimethyl-2,4-hexadiene (24). The mechanisms for these transformations are discussed.

Isomérisation thermique de vinyl-2 aziridines N-substituées

1976 ◽  
Vol 54 (10) ◽  
pp. 1590-1598 ◽  
Author(s):  
Daniel Borel ◽  
Yvonne Gelas-Mialhe ◽  
Roger Vessière
Keyword(s):  
Double Bond ◽  
Thermal Isomerization ◽  
Experimental Results ◽  
Phenyl Substituent ◽  
Ethylene Imine ◽  
Ring Carbon ◽  
Reaction Proceeds

The thermal isomerization of 2-vinylaziridines, variously substituted on the ring and the double bond, has been studied. The nature of the products formed depends on the nature of the substituents in positions 1 and 3. If the ring carbon-3 carries a phenyl substituent, the thermolysis yields, in most cases, a Δ-2-pyrroline. With unsubstituted or 3-alkylaziridines the reaction proceeds, depending on the nature of the substituent on the nitrogen, either to an ethylene imine or to a mixture of Δ-2- and Δ-3-pyrrolines. Mechanisms to interpret the experimental results are proposed. [Journal translation]

Natural and Synthetic Rubber. I. Products of the Destructive Distillation of Natural Rubber

1929 ◽  
Vol 2 (3) ◽  
pp. 441-451 ◽  
Author(s):  
Thomas Midgley ◽  
Albert L. Henne
Keyword(s):  
Experimental Data ◽  
Natural Rubber ◽  
Atmospheric Pressure ◽  
Experimental Results ◽  
Double Bonds ◽  
Synthetic Rubber ◽  
Single Bonds ◽  
Natural And Synthetic

Abstract Two hundred pounds of pale crepe rubber have been destructively-distilled at atmospheric pressure. The distillate was fractionated and its components identified from C5 to C10, as shown in the table. Assuming that the Staudinger formula is correct, that the single bonds furthest from the double bonds are the weaker spots and that the formation of six-carbon rings is favored, it has been shown that nearly all of the compounds actually isolated could be predicted. The experimental results, together with forthcoming experimental data, are expected to be used to throw light upon the formula of the rubber molecule.

Synthesis and stereochemistry of 5-substituted quinuclidine-2-carboxylic acids with semicyclic double bonds

1971 ◽  
Vol 4 (5) ◽  
pp. 636-639
Author(s):  
L. N. Yakhontov ◽  
L. I. Mastafanova ◽  
K. F. Turchin ◽  
T. D. Pervacheva ◽  
M. V. Rubtsov
Keyword(s):  
Carboxylic Acids ◽  
Double Bonds

Application of the Intramolecular Diels–Alder Vinylarenе (IMDAV) Approach for the Synthesis of Thieno[2,3-f]isoindoles

Synthesis ◽  
2020 ◽  
Vol 52 (15) ◽  
pp. 2196-2223
Author(s):  
Mykola D. Obushak ◽  
Fedor I. Zubkov ◽  
Maryana A. Nadirova ◽  
Yevhen-Oleh V. Laba ◽  
Vladimir P. Zaytsev ◽  
...  
Keyword(s):  
Nitrogen Atom ◽  
Transition State ◽  
Carboxylic Acids ◽  
Diels Alder ◽  
Reaction Sequence ◽  
X Ray ◽  
Single Diastereomer ◽  
Reaction Proceeds

3-(Thien-2-yl)- and 3-(thien-3-yl)allylamines, readily accessible from the corresponding thienyl aldehydes, can interact with a broad range of anhydrides and α,β-unsaturated acids chlorides (maleic, сitraconic­, and phenyl maleic anhydrides, сrotonyl and сinnamyl chlorides, etc.) leading to the formation of a thieno[2,3-f]isoindole core. Usually, the reaction sequence involves three successive steps: acylation of the nitrogen atom of the initial allylamine, the intramolecular Diels–Alder vinylarenе (IMDAV) reaction, and the final aromatization of the dihydrothiophene ring in the Diels–Alder adducts. The scope and limitations of the proposed method were thoroughly investigated. It was revealed with the aid of X-ray analysis that the key step, the IMDAV reaction, proceeds through an exo-transition state, giving rise to the exclusive formation of a single diastereomer of the target heterocycle. In the case of maleic anhydrides, the method allows to obtain functionally substituted thieno[2,3-f]isoindole carboxylic acids, which are potentially useful substrates for further transformations and subsequent bioscreening.

7,10-Dibromo-2,3-dicyanopyrazinophenanthrene Aggregates as a Photosensitizer for Nickel-Catalyzed Aryl Esterification

Synlett ◽  
2021 ◽  
Author(s):  
Xiaoqiang Yu ◽  
Min He ◽  
Shilei Yang ◽  
Ming Bao
Keyword(s):  
Visible Light ◽  
Carboxylic Acids ◽  
Bond Formation ◽  
Cross Coupling ◽  
Aryl Halides ◽  
Ni Catalyst ◽  
Coupling Reactions ◽  
Formation Reaction ◽  
Cross Coupling Reactions ◽  
Reaction Proceeds

AbstractSelf-assembled aggregates of 7,10-dibromo-2,3-dicyanopyrazinophenanthrene which act as a new organophotocatalyst in combination with Ni catalyst for the Caryl–Oacyl cross-coupling reactions of carboxylic acids with aryl halides are described. This visible-light-induced Caryl–Oacyl bond-formation reaction proceeds smoothly to afford aryl esters with satisfactory to excellent yields.

One-Pot Synthesis of 2-Substituted Benzoxazoles Directly from Carboxylic Acids

2008 ◽  
Vol 61 (11) ◽  
pp. 881 ◽  
Author(s):  
Dinesh Kumar ◽  
Santosh Rudrawar ◽  
Asit K. Chakraborti
Keyword(s):  
Carboxylic Acids ◽  
Methanesulfonic Acid ◽  
Acid Chlorides ◽  
Double Bonds ◽  
Reaction Conditions ◽  
One Pot ◽  
Effective Catalyst ◽  
One Pot Synthesis ◽  
Highly Effective

Methanesulfonic acid has been found to be a highly effective catalyst for a convenient and one-pot synthesis of 2-substituted benzoxazoles by the reaction of 2-aminophenol with acid chlorides, generated in situ from carboxylic acids. Aryl, heteroaryl, and arylalkyl carboxylic acids provided excellent yields of the corresponding benzoxazoles. The reaction conditions were compatible with various substituents such as chloro, bromo, nitro, methoxy, cyclopentyloxy, phenoxy, thiophenoxy, and conjugated double bonds. Benzoxazole formation was found to be general with respect to substituted 2-aminophenols.

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