- Indium-Catalyzed C?F Bond Transformation through Oxymetalation/β-Fluorine Elimination to Access Fluorinated Isocoumarins
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Fluorinated heterocycles have attracted much attention in the pharmaceutical and agrochemical industries. Many strategies have already been developed to achieve the synthesis of fluorinated heterocycles. Formidable challenges remain, however, in the synthesis of fluorinated isocoumarin derivatives that are among the most alluring structural motifs. Herein, the indium-catalyzed C?F bond transformation of 2-(2,2-difluorovinyl) benzoates is reported, which are readily accessible compounds, to give a diverse array of fluorinated isocoumarins. The present reaction proceeds smoothly using inexpensive reagents: a catalytic amount of indium salt in the presence of zinc salt. A theoretical calculation of potential energy profiles showed that the reaction consists of oxymetalation with the elimination of alkyl halide and the β-fluorine elimination.
- Yata, Tetsuji,Nishimoto, Yoshihiro,Chiba, Kouji,Yasuda, Makoto
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supporting information
p. 8288 - 8294
(2021/05/21)
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- Synthesis of chiral isoindolinones via asymmetric propargylation/lactamization cascade
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A Zn-mediated propargylation/lactamization cascade reaction with chiral 2-formylbenzoate derived N-tert-butanesulfinyl imines was realized, which provided a practical and efficient method for the synthesis of chiral isoindolinones. High diastereoselectivities (up to 97:3 dr) and good reaction yields were observed for most examined cases.
- Meng, Jiao-Long,Jiao, Tang-Qian,Chen, Ya-Heng,Fu, Rui,Zhang, Shu-Sheng,Zhao, Qian,Feng, Chen-Guo,Lin, Guo-Qiang
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p. 1564 - 1567
(2018/03/23)
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- Highly enantioselective synthesis of 2,3-dihydro-1 H-imidazo[2,1-a isoindol-5(9b H)-ones via catalytic asymmetric intramolecular cascade imidization-nucleophilic addition-lactamization
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Highly enantioselective catalytic asymmetric intramolecular cascade imidization-nucleophilic addition-lactamization of N1-alkylethane-1,2-diamine with methyl 2-formylbenzoate catalyzed by a chiral phosphoric acid represents the first efficient method for the preparation of medicinally interesting chiral 2,3-dihydro-1H-imidazo[2,1-a]isoindol-5(9bH)-ones with high yields and excellent enantioselectivities. This strategy has been shown to be quite general toward various methyl 2-formylbenzoates.
- He, Yuwei,Cheng, Chuyu,Chen, Bin,Duan, Kun,Zhuang, Yue,Yuan, Bo,Zhang, Meisan,Zhou, Yougui,Zhou, Zihong,Su, Yu-Jun,Cao, Rihui,Qiu, Liqin
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p. 6366 - 6369
(2015/01/16)
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- Synthesis of chiral 3-substituted phthalides by a sequential organocatalytic enantioselective aldol-lactonization reaction. Three-step synthesis of (S)-(-)-3-butylphthalide
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(Chemical Equation Presented) The development of efficient methods for the facile construction of important molecular frameworks is an important goal in organic synthesis. Chiral 3-substituted phthalides are widely distributed in a large collection of natural products with broad, potent, and potentially path-pointing biological activities. In this investigation, we have uncovered an unprecedented organocatalytic asymmetric aldol-lactonization reaction of 2-formylbenzoic esters with ketones/aldehydes for convenient construction of the enantioenriched "privileged" scaffold. As a result of the sensitive nature of substrate structures of an organocatalytic enantioselective aldol reaction, after extensive optimization of reaction conditions, catalyst L-prolinamide alcohol IV is identified as the best promoter. Interestingly, it is found that in this reaction, addition of an acid additive PhCO2H can significantly enhance reaction efficiency with use of only as low as 2.5 mol % IV for the process. Moreover, due to the sensitivity of reaction conditions toward a sequential aldol-lactonization process without affecting enantioselectivity and racemization, it is essential to remove the catalyst for the subsequent facile lactonization reaction in the presence of K 2CO3. The aldol-lactonization processes serve as a powerful approach to the preparation of synthetically and biologically important 3-substitued phthalides with a high level of enantioselectivities. A 3-step catalytic asymmetric synthesis of the natural product of 3-butylphthalide is reported.
- Zhang, Haoyi,Zhang, Shilei,Liu, Lu,Luo, Guangshun,Duan, Wenhu,Wang, Wei
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supporting information; experimental part
p. 368 - 374
(2010/03/30)
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