- Chromium-Catalyzed Reductive Cleavage of Unactivated Aromatic and Benzylic C-O Bonds
-
Reductive cleavage of aromatic and benzylic C-O bonds by chromium catalysis is reported. This deoxygenative reaction was promoted by low-cost CrCl 2precatalyst combined with poly(methyl hydrogen siloxane) as the mild reducing agent, providing a strategy in forming reduced motifs by cleavage of unactivated C-O bonds. A range of functional groups such as bromide, chloride, fluoride, hydroxyl, amino, and alkoxycarbonyl can be retained in the reduction.
- Yuan, Shuqing,Ling, Liang,Tang, Jinghua,Luo, Meiming,Zeng, Xiaoming
-
supporting information
p. 3343 - 3350
(2021/07/02)
-
- Copper acetate-DMSO promoted methylthiolation of arenes and heteroarenes
-
An unprecedented copper acetate-DMSO promoted methylthiolation of arenes and heteroarenes in the presence of air has been developed. The reaction is highly regioselective under the directing group influence of pyridine and pyrimidine functional units and gives the thiomethylated product in moderate to high yields.
- Sharma, Poonam,Rohilla, Sandeep,Jain, Nidhi
-
p. 4116 - 4122
(2015/05/05)
-
- Deprotonative metalation of aromatic compounds by using an amino-based lithium cuprate
-
Deprotonative cupration of aromatic compounds by using amino-based lithium cuprates was optimized with 2,4-dimethoxypyrimidine and 2-methoxypyridine as the substrates and benzoyl chloride as the electrophile. [(tmp)2CuLi] (+2 LiCl) (tmp=2,2,6,6-tetramethylpiperidino) was identified as the best reagent and its use was extended to anisole, 1,4-dimethoxybenzene, other substituted pyridines, furan, thiophene and derivatives, and N-Boc-indole (Boc=tert-butyloxycarbonyl). Of the electrophiles employed to attempt the interception of the generated aryl cuprates, aroyl chlorides, iodomethane, and diphenyl disulfide efficiently reacted. In addition, different oxidative agents were identified to afford symmetrical biaryls. Finally, palladium-catalyzed coupling with aryl halides was optimized and allowed the synthesis of different aryl derivatives in medium to good yields.
- Nguyen, Tan Tai,Marquise, Nada,Chevallier, Floris,Mongin, Florence
-
experimental part
p. 10405 - 10416
(2011/10/12)
-
- [Pd(Cl)2(P(NC5H10)(C6H 11)2)2] - A highly effective and extremely versatile palladium-based negishi catalyst that efficiently and reliably operates at low catalyst loadings
-
[Pd(Cl)2(P(NC5H10)-(C6H 11)2]2] (1) has been prepared in quantitative yield by reacting commercially available [Pd(cod)(Cl)2] (cod = cyclooctadiene) with readily prepared 1-(dicyclohexylphosphanyl)piperidine in toluene under N2 within a few minutes at room temperature. Complex 1 has proved to be an excellent Negishi catalyst, capable of quantitatively coupling a wide variety of electronically activated, non-activated, deactivated, sterically hindered, heterocyclic, and functionalized aryl bromides with various (also heterocyclic) arylzinc reagents, typically within a few minutes at 100°C in the presence of just 0.01 mol% of catalyst. Aryl bromides containing nitro, nitrile, ether, ester, hydroxy, carbonyl, and carboxyl groups, as well as acetais, lactones, amides, anilines, alkenes, carboxylic acids, acetic acids, and pyridines and pyrimidines, have been successfully used as coupling partners. Furthermore, electronic and steric variations are tolerated in both reaction partners. Experimental observations strongly indicate that a molecular mechanism is operative.
- Bolliger, Jeanne L.,Frech, Christian M.
-
experimental part
p. 11072 - 11081
(2010/11/16)
-
- Photo-Arylation. IV. Synthesis of 2-Arylpyridines by Photo-Reaction of 2-Iodopyridine with Substituted Benzenes
-
Photolysis of a mixture of 2-iodopyridine and a variety of substituted benzenes in dichloromethane afforded the corresponding 2-arylpyridines as isomeric mixtures.Based on the isomer distributions of the products and the formation of 2-chloropyridine as a by-product, the reactivity of 2-iodopyridine in the present reaction was suggested to be electrophilic in character.Keywords - arylpyridine; 2-pyridinylation; photo-arylation; photolysis; 2-iodopyridine; homolytic aromatic substitution
- Terashima, Masanao,Seki, Koh-ichi,Yoshida, Chihiro,Ohkura, Kazue,Kanaoka, Yuichi
-
p. 1009 - 1015
(2007/10/02)
-