- Rhodium-Catalyzed Electrooxidative C?H Olefination of Benzamides
-
Metal-catalyzed chelation-assisted C?H olefinations have emerged as powerful tools for the construction of functionalized alkenes. Herein, we describe the rhoda-electrocatalyzed C?H activation/alkenylation of arenes. The olefinations of challenging electron-poor benzamides were thus accomplished in a fully dehydrogenative fashion under electrochemical conditions, avoiding stoichiometric chemical oxidants, and with H2 as the only byproduct. This versatile alkenylation reaction also features broad substrate scope and used electricity as a green oxidant.
- Ackermann, Lutz,Struwe, Julia,Zhang, Yan
-
supporting information
p. 15076 - 15080
(2020/06/20)
-
- Ruthenium-Catalyzed Synthesis of N-Methylated Amides using Methanol
-
An efficient synthesis of N-methylated amides using methanol in the presence of a ruthenium(II) catalyst is realized. Notably, applying this process, tandem C-methylation and N-methylation were achieved to synthesize α-methyl N-methylated amides. In addition, several kinetic studies and control experiments with the plausible intermediates were performed to understand this novel protocol. Furthermore, detailed computational studies were carried out to understand the mechanism of this transformation.
- Paul, Bhaskar,Panja, Dibyajyoti,Kundu, Sabuj
-
supporting information
p. 5843 - 5847
(2019/08/26)
-
- Modular Dual-Tasked C-H Methylation via the Catellani Strategy
-
We report a dual-tasked methylation that is based on cooperative palladium/norbornene catalysis. Readily available (hetero)aryl halides (39 iodides and 4 bromides) and inexpensive MeOTs or trimethylphosphate are utilized as the substrates and methylating reagent, respectively. Six types of "ipso" terminations can modularly couple with this "ortho" C-H methylation to constitute a versatile methylation toolbox for preparing diversified methylated arenes. This toolbox features inexpensive methyl sources, excellent functional-group tolerance, simple reaction procedures, and scalability. Importantly, it can be uneventfully extended to isotope-labeled methylation by switching to the corresponding reagents CD3OTs or 13CH3OTs. Moreover, this toolbox can be applied to late-stage modification of biorelevant substrates with complete stereoretention. We believe these salient and practical features of our dual-tasked methylation toolbox will be welcomed by academic and industrial researchers.
- Gao, Qianwen,Shang, Yong,Song, Fuzhen,Ye, Jinxiang,Liu, Ze-Shui,Li, Lisha,Cheng, Hong-Gang,Zhou, Qianghui
-
supporting information
p. 15986 - 15993
(2019/10/11)
-
- Chemoselective Synthesis of Aryl Ketones from Amides and Grignard Reagents via C(O)-N Bond Cleavage under Catalyst-Free Conditions
-
Conversion of a wide range of N-Boc amides to aryl ketones was achieved with Grignard reagents via chemoselective C(O)-N bond cleavage. The reactions proceeded under catalyst-free conditions with different aryl, alkyl, and alkynyl Grignard reagents. α-Ketoamide was successfully converted to aryl diketones, while α,β-unsaturated amide underwent 1,4-addition followed by C(O)-N bond cleavage to provide diaryl propiophenones. N-Boc amides displayed higher reactivity than Weinreb amides with Grignard reagents. A broad substrate scope, excellent yields, and quick conversion are important features of this methodology.
- Sureshbabu, Popuri,Azeez, Sadaf,Muniyappan, Nalluchamy,Sabiah, Shahulhameed,Kandasamy, Jeyakumar
-
p. 11823 - 11838
(2019/10/02)
-
- Manganese-catalyzed directed methylation of C(sp2)-H bonds at 25 °C with high catalytic turnover
-
We report here a manganese-catalyzed C-H methylation reaction of considerable substrate scope, using MeMgBr, a catalytic amount of MnCl2· 2LiCl, and an organic dihalide oxidant. The reaction features ambient temperature, low catalyst loading, typically 1%, high catalytic turnover reaching 5.9 × 103, and no need for an extraneous ligand and illustrates a unique catalytic use of simple manganese salts for C-H activation, which so far has relied on catalysis by manganese carbonyls.
- Sato, Takenari,Yoshida, Takumi,Al Mamari, Hamad H.,Ilies, Laurean,Nakamura, Eiichi
-
supporting information
p. 5458 - 5461
(2017/11/06)
-
- Oxidation of Aromatic Compounds. V. Oxidation of Substituted Benzonitriles and 2,4,6-Triaryl-1,3,5-Triazines in System HSO3F-PbO2
-
Low-temperature oxidation of substituted benzonitriles by the system HSO3F-PbO2 proceeds with intermediate formation of cation-radicals and leads to substitution of hydrogen atoms of the methyl group or benzene ring. This reaction provides a route for preparation of chloromethylsubstituted benzonitriles, diarylmethanes, diaryls, arylfluorosulfonates and substituted benzamides with cyano groups. In the case of methyl derivatives of 2,4,6-triphenyl-1,3,5-triazine substitution of the first and then the second hydrogen atom of the same methyl group transforms it into hydroxy or chloromethyl group, or into the aldehyde function.
- Rudenko,Salfetnikova,Vasil'ev
-
p. 1447 - 1470
(2007/10/03)
-