1689-09-4Relevant academic research and scientific papers
A new ring enlargement reaction of γ-lactones to seven-membered cyclic ethers via intramolecular endo-mode cyclisation of the ω-hydroxy allenyl ketone intermediates in situ
Nagao, Yoshimitsu,Jeong, Ill-Yun,Lee, Woo Song,Sano, Shigeki
, p. 19 - 20 (1996)
Phthalides 1a-f were treated with prop-2-ynylmagnesium bromide followed by treatment with 20% HCl in one pot to give the corresponding seven-membered cyclic ethers, benzoxepins 4a-f.
Electron-Transfer-Induced Intramolecular Heck Carbonylation Reactions Leading to Benzolactones and Benzolactams
Fukuyama, Takahide,Bando, Takanobu,Ryu, Ilhyong
, p. 3015 - 3021 (2018)
A metal-catalyst-free intramolecular Heck carbonylation reaction of benzyl alcohols and benzyl amines with carbon monoxide under heating at 250 °C affords the corresponding benzolactones and benzolactams in good to excellent yields. A hybrid radical/ionic chain mechanism, involving electron transfer from radical anions generated by nucleophilic attack of alcohols or amines on intermediate acyl radicals, is proposed.
Enantioselective Transfer Hydrogenation of Oxocarbenium Ions Enables Asymmetric Access to α-Substituted 1,3-Dihydroisobenzofurans
Zhou, Likai,Jia, Kuiyong,Liu, Xigong,Liu, Lei
supporting information, p. 421 - 428 (2021/10/01)
Reported here is an efficient enantioselective transfer hydrogenation of cyclic oxocarbenium ions generated in situ through collapse of the corresponding acetal substrates. The asymmetric approach provides straightforward access to a variety of chiral α-aryl substituted 1,3-dihydroisobenzofurans in high yields with excellent enantioselectivities. α-Alkynyl substituted 1,3-dihydroisobenzofurans were also proved to be suitable substrates. In addition, when the reaction was performed at gram scale, the desired product was obtained in good yields with excellent enantioselectivity.
Phthalide synthesis through dehydrogenated lactonization of the C(sp3)-H bond by photoredox catalysis
Cai, Shunyou,Cai, Zhixiong,Chen, Shanyi,Huang, Mingqiang,Lai, Qihong,Lin, Yulin,Liu, Chao,Liu, Hui
, p. 8212 - 8216 (2021/10/29)
A practical and efficient method is established for the direct oxidative lactonization of the C(sp3)-H bonds relying on visible-light-induced photoredox catalysis. This protocol expediently allows the delivery of diverse phthalides using oxygen as the sole terminal oxidant under metal-free conditions at room temperature. Notably, the choice of an appropriate hydrogen atom transfer (HAT) cocatalyst is revealed to be critical for the success of this process.
Illuminating the norepinephrine transporter: fluorescent probes based on nisoxetine and talopram
Camacho-Hernandez, Gisela Andrea,Casiraghi, Andrea,Guthrie, Daryl A.,Ku, Therese C.,Luethi, Dino,Newman, Amy Hauck,Rudin, Deborah,Schütz, Gerhard J.,Sitte, Harald H.,Straniero, Valentina,Valoti, Ermanno
, p. 1174 - 1186 (2021/10/27)
The utilization of fluorescent ligands to study the monoamine transporters (MATs) has increased our knowledge of their function and distribution in live cell systems. In this study, we extend SAR for nisoxetine and talopram as parent compounds, to identif
Copper-catalyzed aerobic double functionalization of benzylic C(sp3)-H bonds for the synthesis of 3-hydroxyisoindolinones
Nozawa-Kumada, Kanako,Matsuzawa, Yuta,Ono, Kanako,Shigeno, Masanori,Kondo, Yoshinori
supporting information, p. 8604 - 8607 (2021/09/02)
A copper-catalyzed aerobic 3-hydroxyisoindolinone synthesis was developed via the benzylic double C(sp3)-H functionalization of 2-alkylbenzamides. In this reaction, molecular oxygen was used as both an oxidant for C(sp3)-H functionalization and an oxygen source. Our method can be extended to diverse benzylic C(sp3)-H bonds and shows excellent functional group tolerance. This journal is
Redox deracemization of α-substituted 1,3-dihydroisobenzofurans
Chen, Xiaohan,Zhao, Ran,Liu, Ziqiang,Sun, Shutao,Ma, Yingang,Liu, Qingyun,Sun, Xia,Liu, Lei
supporting information, p. 2305 - 2308 (2021/03/08)
Chiral α-substituted 1,3-dihydroisobenzofurans are key scaffolds in a number of bioactive natural products and synthetic pharmaceuticals. However, catalytic asymmetric approaches have been rarely developed. Here, a redox deracemization technology is adopted to address the catalytic asymmetric synthesis. A broad range of α-aryl substituted 1,3-dihydroisobenzofurans are effectively deracemized in high efficiency with excellent ee. α-Alkynyl substituted ethers were also compatible with the deracemization technology.
Visible Light-Promoted Magnesium, Iron, and Nickel Catalysis Enabling C(sp3)-H Lactonization of 2-Alkylbenzoic Acids
Li, Sasa,Su, Mincong,Sun, Jie,Hu, Kunjun,Jin, Jian
supporting information, p. 5842 - 5847 (2021/07/31)
A mild and practical C(sp3)-H lactonization protocol has been achieved by merging photocatalysis and magnesium (iron, nickel) catalysis. A diverse range of 2-alkylbenzoic acids with a variety of substitution patterns could be transformed into the corresponding phthalide products. Based on the mechanistic experimentation and reported prior studies, a possible mechanism for the benzylic oxidative lactonization reaction was proposed with the hypothetic photoactive ternary complex formed between the 2-alkylbenzoic acid substrate, magnesium ion, and bromate anion.
Cerium(IV) Carboxylate Photocatalyst for Catalytic Radical Formation from Carboxylic Acids: Decarboxylative Oxygenation of Aliphatic Carboxylic Acids and Lactonization of Aromatic Carboxylic Acids
Hirosawa, Keishi,Mashima, Kazushi,Satoh, Tetsuya,Shinohara, Koichi,Shirase, Satoru,Tamaki, Sota,Tsurugi, Hayato
supporting information, (2020/03/25)
We found that in situ generated cerium(IV) carboxylate generated by mixing the precursor Ce(OtBu)4 with the corresponding carboxylic acids served as efficient photocatalysts for the direct formation of carboxyl radicals from carboxylic acids under blue light-emitting diodes (blue LEDs) irradiation and air, resulting in catalytic decarboxylative oxygenation of aliphatic carboxylic acids to give C-O bond-forming products such as aldehydes and ketones. Control experiments revealed that hexanuclear Ce(IV) carboxylate clusters initially formed in the reaction mixture and the ligand-to-metal charge transfer nature of the Ce(IV) carboxylate clusters was responsible for the high catalytic performance to transform the carboxylate ligands to the carboxyl radical. In addition, the Ce(IV) carboxylate cluster catalyzed direct lactonization of 2-isopropylbenzoic acid to produce the corresponding peroxy lactone and ?3-lactone via intramolecular 1,5-hydrogen atom transfer (1,5-HAT).
Preparation method of 10,10-dimethylanthrone
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Paragraph 0025; 0026; 0029; 0030, (2019/06/30)
The invention belongs to the field of drug synthesis and provides a novel method of synthesizing melitracen hydrochloride intermediate 10,10-dimethylanthrone. The 10,10-dimethylanthrone is prepared from phthalic anhydride as a start material through two-step Grignard reaction and three-step closed-ring reaction. The total yield is up to 30%, and the purity of the finished intermediate is higher than 98.0%. Compared with traditional synthetic processes, the novel process herein has simple steps and greatly reduced production cost, causes little environmental pollution and helps greatly solve the environmental issue caused by the production of 10,10-dimethylanthrone.
