- Continuous Electrochemical Synthesis of Iso-Coumarin Derivatives from o-(1-Alkynyl) Benzoates under Metal- and Oxidant-Free
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A non-oxidant and metal-free strategy for synthesizing iso-coumarin by using a continuous electrochemical microreactor to initiate an oxidative cyclization reaction of o-(1-alkynyl) benzoate and radicals. This efficient and clean continuous electrosynthesis method not only avoids the complicated gas protection operation and production of by-products in the batch processes, but also help to overcome the difficulty that batch metal catalysis and electrocatalysis are difficult to scale up, and has the potential for pilot-scale experiment.
- Lin, Xinxin,Fang, Zheng,Zeng, Cuilian,Zhu, Chenlong,Pang, Xinyan,Liu, Chengkou,He, Wei,Duan, Jindian,Qin, Ning,Guo, Kai
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supporting information
p. 13738 - 13742
(2020/10/02)
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- p-TSA-Based DESs as “Active Green Solvents” for Microwave Enhanced Cyclization of 2-Alkynyl-(hetero)-arylcarboxylates: an Alternative Access to 6-Substituted 3,4-Fused 2-Pyranones
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In this paper, we describe the use of p-TSA based Deep Eutectic Solvents (DESs) as alternative environmental-friendly “active” solvents for the microwave-mediated synthesis of 6-substituted 3,4-fused 2-pyranones, and in particular isocoumarins, starting from 2-alkynyl-(hetero)arylcarboxylates. When the alkyne terminus bears a neutral or an electron-donating group (EDG), the reactions are fast, clean and highly regioselective, to give the 6-endo-dig cyclization products in good to excellent yields. For substrates bearing an electron-withdrawing group (EWG) on the alkyne end, the regioselectivity can be tuned by adding a small amount of silver(I) triflate as co-catalyst. DES was demonstrated to be reusable without loss of efficiency in terms of reaction yields. Based on experimental evidence and previous findings, two competitive mechanisms working simultaneously are proposed to explain the outcomes and the regioselectivity issues.
- Curti, Fabiola,Tiecco, Matteo,Pirovano, Valentina,Germani, Raimondo,Caselli, Alessandro,Rossi, Elisabetta,Abbiati, Giorgio
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p. 1904 - 1914
(2019/02/26)
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- Gold promoted arylative cyclization of alkynoic acids with arenediazonium salts
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Alkynoic acids derived from salicylic acid and analogues undergo arylative cyclization with arenediazonium salts promoted by gold in the absence of external ligands. The reaction is thermally induced and proceeds even in the absence of light. A difference in regioselectivity has been found compared with that observed in the cycloisomerization process of the same type of compounds.
- Carrillo-Arcos, Ulises A.,Porcel, Susana
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supporting information
p. 1837 - 1842
(2018/03/23)
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- Divergent Syntheses of (Z)-3-Alkylideneisobenzofuran-1(3 H)-ones and 1 H-Isochromen-1-ones by Copper-Catalyzed Cycloisomerization of 2-Alkynylbenzoic Acids in Ionic Liquids
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The cycloisomerization of readily available 2-alkynylbenzoic acids 1 in ionic liquids (ILs) as recyclable reaction media has been studied under the catalytic action of CuCl2. With substrates bearing an aryl group on the triple bond, a mixture o
- Mancuso, Raffaella,Pomelli, Christian S.,Chiappetta, Piera,Gioia, Katia F.,Maner, Asif,Marino, Nadia,Veltri, Lucia,Chiappe, Cinzia,Gabriele, Bartolo
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p. 6673 - 6680
(2018/06/01)
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- Divergent syntheses of iodinated isobenzofuranones and isochromenones by iodolactonization of 2-alkynylbenzoic acids in ionic liquids
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The regiochemical outcome of the iodolactonization of 2-alkynylbenzoic acids, carried out at 100 °C in ionic liquids (ILs) as unconventional solvents and with molecular iodine as the iodine source, in the absence of external bases, was found to be strongl
- Mancuso, Raffaella,Pomelli, Christian C.,Malafronte, Francesco,Maner, Asif,Marino, Nadia,Chiappe, Cinzia,Gabriele, Bartolo
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supporting information
p. 4831 - 4841
(2017/07/10)
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- Synthesis of isocoumarins: Rhenium complex-catalyzed cyclization of 2-ethynylbenzoic acids
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When 2-ethynylbenzoic acids were treated with a catalytic amount of a rhenium complex, such as ReCl(CO)5, 6-endo cyclization of 2-ethynylbenzoic acids proceeded with a high selectivity to give the corresponding isocoumarins in moderate to good yields.
- Umeda, Rui,Yoshikawa, Shunya,Yamashita, Kouji,Nishiyama, Yutaka
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p. 2172 - 2179
(2015/12/12)
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- Palladium(II)-catalyzed tandem annulation reaction of o-alkynylbenzoates with methyl vinyl ketone for the synthesis of isocoumarins
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A palladium(II)-catalyzed highly regioselective tandem reactions of o-alkynylbenzoates with methyl vinyl ketone for the synthesis of isocoumarins was developed. It is a convenient, mild and environmentally benign reaction with moderate to high yield. The
- Wang, Huan,Han, Xiuling,Lu, Xiyan
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p. 8626 - 8631
(2013/09/12)
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- Halocyclization of methyl 2-alkynylbenzoates to isocoumarins using cupric halides
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Treatment of methyl 2-alkynylbenzoates with two to three equivalents of CuX2 (X = Cl or Br) in refluxing acetonitrile gave isocoumarins 2 in good to excellent chemical yields.
- Chin, Ling-Yu,Lee, Chia-Ying,Lo, Yu-Hsiang,Wu, Ming-Jung
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body text
p. 643 - 648
(2009/05/11)
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