17041-46-2Relevant academic research and scientific papers
One-pot cascade synthesis of 2,3-disubstituted 2,3-dihydrobenzofurans via ortho-quinone methide intermediates generated in situ
Shaikh, Abdul Kadar,Varvounis, George
, p. 14892 - 14896 (2015)
A simple and efficient one-pot cascade reaction for the regioselective synthesis of trans or cis/trans 2,3-disubstituted 2,3-dihydrobenzofurans is reported. The method involves fluoride-induced desilylation, generation of o-quinone methide (o-QM) by chloride or nitrate anion elimination, Michael addition and intramolecular 5-exo-tet elimination of a bromide anion. Nitrate, acetoxy and chloride anions are compared as leaving groups in the formation of the in situ generated o-QM.
Expeditious synthesis of bicyclic pyrrolidine/pyrrolizidine/thiazolidine grafted macrocycles through intramolecular 1,3-dipolar cycloaddition of azomethine ylides
Purushothaman,Prasanna,Raghunathan
, p. 6450 - 6454 (2013)
Stereoselective synthesis of bicyclic pyrrolidine and pyrrolizidine grafted macrocycles has been accomplished through intramolecular 1,3-dipolar cycloaddition (1,3-DC) reaction. Alkenyl aldehydes 4a-b derived from salicylaldehyde have been reacted with se
Coumarins by Direct Annulation: β-Borylacrylates as Ambiphilic C3-Synthons
Wienhold, Max,Molloy, John J.,Daniliuc, Constantin G.,Gilmour, Ryan
supporting information, p. 685 - 689 (2020/11/30)
Modular β-borylacrylates have been validated as programmable, ambiphilic C3-synthons in the cascade annulation of 2-halo-phenol derivatives to generate structurally and electronically diverse coumarins. Key to this [3+3] disconnection is the BPin unit which serves a dual purpose as both a traceless linker for C(sp2)–C(sp2) coupling, and as a chromophore extension to enable inversion of the alkene geometry via selective energy transfer catalysis. Mild isomerisation is a pre-condition to access 3-substituted coumarins and provides a handle for divergence. The method is showcased in the synthesis of representative natural products that contain this venerable chemotype. Facile entry into π-expanded estrone derivatives modified at the A-ring is disclosed to demonstrate the potential of the method in bioassay development or in drug repurposing.
Free radical scavenging and α-glucosidase inhibitory activity of (E)-methyl/ethyl-3-(2-hydroxyphenyl)acrylates
Harikrishna, G.,Hariprasad, K. Siva,Raju, B. China,Tiwari, A. K.,Zehra, A.
, p. 111 - 116 (2021/09/28)
(E)-Methyl/ethyl-3-(2-hydroxyphenyl)acrylates 3a-x have been prepared by the reaction of salicylaldehydes 1a-l with Wittig reagents such as methyl (triphenylphosphoranylidene)acetate 2a and ethyl (triphenylphosphoranylidene)acetate 2b in dry DCM at room t
Visible-Light-Induced C(sp2)-C(sp3) Coupling Reaction for the Regioselective Synthesis of 3-Functionalized Coumarins
Li, Hanjie,Lin, Zhenwei,Lu, Ping,Qiao, Li,Wang, Yanguang,Xie, Jianwei,Zhang, Ke
supporting information, p. 9552 - 9562 (2021/07/26)
A photocatalysis strategy for the regioselective synthesis of 3-functionalized coumarins is reported. With visible light irradiation, a direct and regioselective C(sp2)-C(sp3) coupling reaction of 3-(2-hydroxyphenyl)acrylates with ethers or thioethers occurs by using Ru(bpy)3Cl2·6H2O as a photocatalyst and TBHP as an oxidant. The cascade process involves alkenylation of the C(sp3)-H bond of ethers and lactonization, furnishing 3-alkylated coumarins as the final products. This approach is characterized by a broad substrate scope, mild reaction conditions, and simplified operation. The synthesis of 3-alkylated coumarins could be realized by a one-pot procedure, starting from commercially available salicylaldehyde.
Platinum complex containing diphosphine meta-position carborane ligand and preparation method and application of platinum complex
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Paragraph 0031; 0035-0038; 0053-0057, (2021/04/17)
The invention relates to a platinum complex containing a diphosphine m-carborane ligand and a preparation method and application of the platinum complex, the method of the platinum complex comprises the following steps: reacting n-BuLi with m-carborane m-
Ruthenium-catalyzed intramolecular arene C(sp2)-H amidation for synthesis of 3,4-dihydroquinolin-2(1 H)-ones
Au, Chi-Ming,Ling, Cho-Hon,Sun, Wenlong,Yu, Wing-Yiu
supporting information, p. 3310 - 3314 (2021/05/29)
We report the [Ru(p-cymene)(l-proline)Cl] ([Ru1])-catalyzed cyclization of 1,4,2-dioxazol-5-ones to form dihydroquinoline-2-ones in excellent yields with excellent regioselectivity via a formal intramolecular arene C(sp2)-H amidation. The reactions of the 2- and 4-substituted aryl dioxazolones proceeds initially through spirolactamization via electrophilic amidation at the arene site, which is para or ortho to the substituent. A Hammett correlation study showed that the spirolactamization is likely to occur by electrophilic nitrenoid attack at the arene, which is characterized by a negative ρ value of -0.73.
Cascade Synthesis of 4-Arylcoumarins: Pd-Catalyzed Arylations and Cyclizations with (E)-Ethyl 3-(2-Hydroxyaryl)acrylates and Triarylantimony Difluorides
Kitamura, Yuki,Matsumura, Mio,Kato, Yukari,Murata, Yuki,Yasuike, Shuji
supporting information, p. 1652 - 1657 (2020/03/05)
Herein, we describe a simple general method for the synthesis of 4-arylcoumarins using pentavalent organoantimony compounds. The reactions of 3-(2-hydroxyaryl)acrylates with triarylantimony difluorides in the presence of Pd(OAc)2 (10 mol-%) and 2,2'-bipyridyl (10 mol-%) at 80 °C under aerobic conditions afforded 4-arylcoumarins in good-to-excellent yields. This protocol involves a cascade oxidative Heck-type arylation followed by cyclization, with all the aryl groups in the triarylantimony difluoride transferred to the coupling products. Triarylantimony difluorides resulted in better outcomes than those obtained with other pentavalent organoantimony or bismuth compounds.
Late-Stage Direct o-Alkenylation of Phenols by PdII-Catalyzed C?H Functionalization
Dou, Yandong,Kenry,Liu, Jiang,Jiang, Jianze,Zhu, Qing
supporting information, p. 6896 - 6901 (2019/05/07)
o-Alkenylation of unprotected phenols has been developed by direct C?H functionalization catalyzed by PdII. This work features phenol group as a directing group and realizes highly site-selective C?H bond functionalization of phenols to achieve the corresponding products in moderate to excellent yields at 60 °C. The advantages of this reaction include unprecedented C?H functionalization using phenol as a directing group, high regioselectivity, good substrate scope, mild reaction conditions, and high efficiency. To the best of our knowledge, this is the first example of a regioselective C?H alkenylation of unprotected phenols utilizing phenolic hydroxyl group as a directing group. The alkenylation of unprotected tyrosine and intramolecular cyclization are also successfully carried out under this catalytic system in good yields. Furthermore, this novel method enables a late-stage modification of complex phenol-containing bioactive molecules toward a diversity-oriented drug discovery.
Rh-Catalyzed Deformylative Coupling of Salicylaldehydes with Acrylates and Acrylamides
Rao, Maddali L.N.,Ramakrishna, Boddu S.
supporting information, p. 5677 - 5683 (2019/05/01)
An unprecedented deformylative coupling of salicylaldehydes to acrylates and acrylamides under Rh-catalyzed conditions is reported. These deformylative couplings afforded o-hydroxycinnamates and o-hydroxycinnamamides with broad functional group tolerance and high chemoselectivity under milder reaction conditions.
