118520-71-1Relevant articles and documents
Continuous Electrochemical Synthesis of Iso-Coumarin Derivatives from o-(1-Alkynyl) Benzoates under Metal- and Oxidant-Free
Lin, Xinxin,Fang, Zheng,Zeng, Cuilian,Zhu, Chenlong,Pang, Xinyan,Liu, Chengkou,He, Wei,Duan, Jindian,Qin, Ning,Guo, Kai
supporting information, p. 13738 - 13742 (2020/10/02)
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.
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
Curti, Fabiola,Tiecco, Matteo,Pirovano, Valentina,Germani, Raimondo,Caselli, Alessandro,Rossi, Elisabetta,Abbiati, Giorgio
, p. 1904 - 1914 (2019/02/26)
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.
Metal-Free Synthesis of 4-Chloroisocoumarins by TMSCl-Catalyzed NCS-Induced Chlorinative Annulation of 2-Alkynylaryloate Esters
Norseeda, Krissada,Chaisan, Nattawadee,Thongsornkleeb, Charnsak,Tummatorn, Jumreang,Ruchirawat, Somsak
, p. 16222 - 16236 (2019/12/25)
4-Chloroisocoumarins can be conveniently prepared from 2-alkynylaryloate esters via the activation of alkynes by electrophilic chlorine, generated in situ from N-chlorosuccinimide (NCS) in the presence of 10 mol % trimethylsilyl chloride (TMSCl), which leads to 6-endo-dig-selective chlorinative annulation to give the desired products in moderate to quantitative yields. The procedure employs readily available reagents and can be conveniently carried out on a wide scope of substrates under mild conditions (0 °C to rt). Furthermore, the reaction is scalable for gram-scale preparation of 4-chloroisocoumarins. Additionally, 4-bromo- and 4-iodoisocoumarins can be prepared in moderate to good yields by replacing NCS with N-bromosuccinimide (NBS) and N-iodosuccinimide (NIS), respectively.
Silver triflate/: P -TSA co-catalysed synthesis of 3-substituted isocoumarins from 2-alkynylbenzoates
Gianni, Jonathan,Pirovano, Valentina,Abbiati, Giorgio
supporting information, p. 3213 - 3219 (2018/05/17)
In this paper, we describe the silver triflate/p-toluenesulfonic acid co-catalysed synthesis of seventeen isocoumarins and two thieno[2,3-c]pyran-7-ones starting from 2-alkynylbenzoates and 3-alkynylthiophene-2-carboxylates, respectively. The reaction proceeds with absolute regioselectivity under mild reaction conditions and low catalyst loading, to afford the desired products in good to excellent yields. A conceivable reaction mechanism is proposed and supported by isotope-exchange tests, 1H NMR studies and ad hoc experiments.
Boron Trichloride-Mediated Synthesis of Indoles via the Aminoboration of Alkynes
Lv, Jiahang,Zhao, Binlin,Liu, Li,Han, Ying,Yuan, Yu,Shi, Zhuangzhi
supporting information, p. 4054 - 4059 (2018/09/25)
We describe an efficient catalyst- and metal-free aminoboration of alkynes to 3-borylated indoles using one of the least expensive boron sources, BCl3. The major dichloro(indolyl)borane products can be used for the in situ construction of usefu
Catalyst-Free Synthesis of Borylated Lactones from Esters via Electrophilic Oxyboration
Faizi, Darius J.,Issaian, Adena,Davis, Ashlee J.,Blum, Suzanne A.
, p. 2126 - 2129 (2016/03/05)
A catalyst-free oxyboration reaction of alkynes is developed. The resulting borylated isocoumarins and 2-pyrones are isolated as boronic acids, pinacolboronate esters, or potassium organotrifluoroborate salts, providing a variety of bench-stable organobor
Synthesis of isocoumarins: Rhenium complex-catalyzed cyclization of 2-ethynylbenzoic acids
Umeda, Rui,Yoshikawa, Shunya,Yamashita, Kouji,Nishiyama, Yutaka
, p. 2172 - 2179 (2015/12/12)
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.
Palladium(II)-catalyzed tandem annulation reaction of o-alkynylbenzoates with methyl vinyl ketone for the synthesis of isocoumarins
Wang, Huan,Han, Xiuling,Lu, Xiyan
, p. 8626 - 8631 (2013/09/12)
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
6-endo-dig Cyclization of heteroarylesters to alkynes promoted by Lewis acid catalyst in the presence of Br?nsted acid
Hellal, Malik,Bourguignon, Jean-Jacques,Bihel, Frédéric J.-J.
, p. 62 - 65 (2008/09/17)
We report a regiocontrolled 6-endo-dig cyclization of 2-(2-arylethynyl)heteroaryl esters occurred under Br?nsted acidic conditions and in the presence of a catalytic amount of Lewis acids such as Cu(OTf)2, AuCl3, or (CF3CO
Transmission of Polar Effects. Part 21. Alkaline Hydrolysis of the 2'- and 4'-substituted 2-Methoxycarbonyldiphenylacetylenes and (Z)-2'- and -4'- Substituted 2-Methoxycarbonylstilbenes and the Ionisation and Esterification, with Diazodiphenylmethane of t
Bowden, Keith,Ghadir, Khalaf D. F.
, p. 1333 - 1338 (2007/10/02)
The rate coefficients for the alkaline hydrolysis of a series of 2'- and 4'-substituted 2-methoxycarbonyldiphenylacetylenes and (Z)-2-methoxycarbonylstilbenes have been determined in 70percent (v/v) dimethyl sulphoxide-water at both 30.0 and 50.0 deg C an
