- Iron-catalyzed arene C-H hydroxylation
-
The sustainable, undirected, and selective catalytic hydroxylation of arenes remains an ongoing research challenge because of the relative inertness of aryl carbon-hydrogen bonds, the higher reactivity of the phenolic products leading to over-oxidized by-products, and the frequently insufficient regioselectivity. We report that iron coordinated by a bioinspired L-cystine-derived ligand can catalyze undirected arene carbon-hydrogen hydroxylation with hydrogen peroxide as the terminal oxidant. The reaction is distinguished by its broad substrate scope, excellent selectivity, and good yields, and it showcases compatibility with oxidation-sensitive functional groups, such as alcohols, polyphenols, aldehydes, and even a boronic acid. This method is well suited for the synthesis of polyphenols through multiple carbon-hydrogen hydroxylations, as well as the late-stage functionalization of natural products and drug molecules.
- Cheng, Lu,Wang, Huihui,Cai, Hengrui,Zhang, Jie,Gong, Xu,Han, Wei
-
-
- Method for promoting iron-catalyzed oxidation of aromatic compound carbon - hydrogen bond to synthesize phenol by ligand
-
The method comprises the following steps: iron is used as - a catalyst metal; a sulfur-containing amino acid or cystine-derived dipeptide is a ligand; and under the common action of hydrogen peroxide as an oxidizing agent, an aromatic compound is synthesized to prepare a phenol. Under the action of an acid as an accelerant and hydrogen peroxide as an oxidizing agent, the aryl carbon - hydrogen bond is directly hydroxylated to form a phenolic compound, and the method for preparing the phenol by the catalytic oxidation reaction has a plurality of advantages. The reaction raw materials, the oxidant and the promoter are wide in source, low in price, environment-friendly and good in stability. The aromatic compound carbon - hydrogen bonds directly participate in the reaction to react in one step to form phenol. The reaction condition is mild, the functional group compatibility and the application range are wide. The reaction selectivity is good; under the optimized reaction conditions, the target product separation yield can reach 85%.
- -
-
Paragraph 0084-0085; 0128
(2021/09/21)
-
- Anchimerically Assisted Selective Cleavage of Acid-Labile Aryl Alkyl Ethers by Aluminum Triiodide and N, N-Dimethylformamide Dimethyl Acetal
-
Aluminum triiodide is harnessed by N,N-dimethylformamide dimethyl acetal (DMF-DMA) for the selective cleavage of ethers via neighboring group participation. Various acid-labile functional groups, including carboxylate, allyl, tert-butyldimethylsilyl (TBS), and tert-butoxycarbonyl (Boc), suffer the conditions intact. The method offers an efficient approach to cleaving catechol monoalkyl ethers and to uncovering phenols from acetal-type protecting groups such as methoxymethyl (MOM), methoxyethoxymethyl (MEM), and tetrahydropyranyl (THP) chemoselectively.
- Sang, Dayong,Yue, Huaxin,Zhao, Zhengdong,Yang, Pengtao,Tian, Juan
-
p. 6429 - 6440
(2020/07/14)
-
- An efficient strategy for protecting dihydroxyl groups of catechols
-
A novel strategy for protecting dihydroxyl groups of catechols has been developed. Base-mediated cyclizations of catechols with 1,3-dibromopropane provided the corresponding benzo[b]1,4-dioxepans, and herefrom the protecting group was easily cleaved by aluminum chloride. The preparation of the antibacterial and antifungal agent 4-(2-aminothiazol-4-yl)benzene-1,2-diol from catechol reliably verified its availability amenable to various harsh reaction conditions. Georg Thieme Verlag Stuttgart - New York.
- Huang, Wei-Bin,Guo, Ying,Jiang, Jian-An,Pan, Xian-Dao,Liao, Dao-Hua,Ji, Ya-Fei
-
supporting information
p. 741 - 746
(2013/05/09)
-
- Zinc Mediated Friedel-Crafts Acylation in Solvent-Free Conditions under Microwave Irradiation
-
Zn powder is found to catalyze the Friedel-Crafts acylation of aromatic compounds with acyl halides efficiently under microwave irradiation in solvent-free conditions. Activated substrates undergo acylation predominantly at the para-position. The Zn powder can be re-used up to six times after simple washing with diethyl ether and dilute HCl.
- Paul, Satya,Nanda, Puja,Gupta, Rajive,Loupy, Andre
-
p. 2877 - 2881
(2007/10/03)
-
- HZSM-5 catalysed regiospecific benzoylation of activated aromatic compounds
-
HZSM-5 has been shown to display a remarkable reaction selectivity in the liquid-phase benzoylation of activated arenes to benzophenones in high yields.
- Paul, Vincent,Sudalai,Daniel, Thomas,Srinivasan
-
p. 2601 - 2602
(2007/10/02)
-
- Photolysis of the Ozonide Derived from 1,4-Benzodioxins. Synthesis of Labile o-Benzoquinones
-
By the photolysis of the ozonide derived from 1,4-benzodioxins, o-benzoquinones were obtained in moderate yields independent of the stability of o-benzoquinones and of the substituent groups, except the nitro group.Through the mechanistic studies, it was indicated that o-benzoquinones were formed through a radical decomposition pathway, while catechols were formed through an ionic decomposition pathway induced by acidic impurities.
- Kashima, Choji,Tomotake, Atsushi,Omote, Yoshimori
-
p. 5616 - 5621
(2007/10/02)
-
- LATINONE, A PHENANTHRENE-1,4-QUINONE FROM DALBERGIA LATIFOLIA
-
Latinone, a substituted phenanthrene-1,4-quinone was isolated from Dalbergia latifolia.The structure was assigned from spectroscopic measurements and a synthesis was carried out using a Diels-Alder reaction to form the ring structure.Key Word Index- Dalbergia latifolia; Leguminosae; latinone; quinone; phenanthrene-1,4-quinone.
- Criodain, Thurlough O.,O'Sullivan, Michael,Meegan, Mary Jane,Donnelly, Dervilla M. X.
-
p. 1089 - 1092
(2007/10/02)
-
- Reactions of Benzoyl Peroxide with 4-Hydroxybiphenyl, 4-Hydroxybenzophenone and 2-Hydroxy-5-methylbenzophenone
-
Interaction of benzoyl peroxide with 4-hydroxybiphenyl (I) and 4-hydroxybenzophenone (IV) leads to ortho-benzoyloxylation, giving 3-benzoyloxylated derivatives.A similar reaction with 2-hydroxy-5-methylbenzophenone (VII) results in dimerisation involving the side methyl group.The phenyl and benzoyl groups, thus do not inhibit benzoyloxylation.The formation of the dimer (VIII) from the ketone (VII) shows that it is difficult to achieve ortho-benzoyloxylation with chelated hydroxyl group.
- Sawhney, K. N.,Mathur, K. B. L.
-
p. 590 - 592
(2007/10/02)
-
- Lipogenesis inhibition by certain esters of substituted benzodioxincarboxylic acids
-
Use as lipogenesis inhibitors in mammals of alkyl esters of certain substituted 2,3-dihydro-1,4-benzodioxincarboxylic acids.
- -
-
-