7577-03-9Relevant academic research and scientific papers
para-Selective arylation and alkenylation of monosubstituted arenes using thianthreneS-oxide as a transient mediator
Chen, Xiao-Yue,Nie, Xiao-Xue,Wu, Yichen,Wang, Peng
supporting information, p. 5058 - 5061 (2020/05/18)
Using thianthreneS-oxide (TTSO) as a transient mediator,para-arylation and alkenylation of mono-substituted arenes have been demonstratedviaapara-selective thianthrenation/Pd-catalyzed thio-Suzuki-Miyaura coupling sequence under mild conditions. This reaction features a broad substrate scope, and functional group and heterocycle tolerance. The versatility of this approach was further demonstrated by late-stage functionalization of complex bioactive scaffolds, and direct synthesis of some pharmaceuticals, including Tetriprofen, Ibuprofen, Bifonazole, and LJ570.
Preparation method of para-substituted aryl compound
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Paragraph 0317-0320, (2020/06/09)
The invention discloses a preparation method of a para-substituted aryl compound shown as a formula (I) which is described in the specfication. The preparation method is characterized by comprising the following step of: subjecting an aryl sulfonium salt shown as a formula (II) which is described in the specfication and boride to a coupling reaction in a solvent in an inert atmosphere under the action of alkali and a palladium catalyst to obtain the para-substituted aryl compound. According to the method, mono-substituted aromatic hydrocarbon is taken as a substrate, the aryl sulfonium salt isconstructed in situ, and the palladium catalyst catalyzes the aryl sulfonium salt constructed in situ to undergo the Suzuki-Miyaura coupling reaction, so a mono-substituted aromatic hydrocarbon para-arylation or alkenylation product is constructed quickly and efficiently. The method is mild in conditions, high in substrate universality and wide in tolerance of a heterocyclic coupling substrate.
Synthesis of α-Arylated Cycloalkanones from Congested Trisubstituted Spiro-epoxides: Application of the House-Meinwald Rearrangement for Ring Expansion
Jeedimalla, Nagalakshmi,Jacquet, Camille,Bahneva, Diana,Youte Tendoung, Jean-Jacques,Roche, Stéphane P.
, p. 12357 - 12373 (2018/09/06)
A three-step sequence for the synthesis of α-arylated cyclohexanones and the most challenging cycloheptanones is reported. First, an efficient one-pot synthesis of β,β'-disubstituted benzylidene cycloalkanes (styrenes) using the palladium-catalyzed Barluenga reaction from readily available feedstock chemicals is described. Furthermore, an epoxidation followed by the House-Meinwald rearrangement (HMR) of spiro-epoxides is reported to produce a number of α-arylated cycloalkanones upon ring expansion. Reactions catalyzed by bismuth triflate underwent quasi-exclusively ring expansion for all substrates (electronically poor and rich), with yields ranging from 15% to 95%, thus demonstrating the difficulty of achieving ring enlargement for electron-deficient spiro-epoxides. On the other hand, by means of catalysis with aluminum trichloride, the rearrangement of spiro-epoxides proceeded typically in high yields and with remarkable regioselectivity on a broader substrate scope. In this case, a switch of regioselectivity was achieved for spiro-epoxides with electron-withdrawing substituents which enable the method to be successfully extended to some chemospecific arene shifts and the synthesis of aldehydes bearing a α-quaternary carbon. While the HMR has been extensively studied for smaller ring enlargement, we are pleased to report herein that larger cyclohexanones and cycloheptanones can be obtained efficiently from more sterically demanding trisubstituted spiro-epoxides bearing electron-releasing and electron-neutral arene substituents.
Cyrene as a Bio-Based Solvent for the Suzuki-Miyaura Cross-Coupling
Wilson, Kirsty L.,Murray, Jane,Jamieson, Craig,Watson, Allan J. B.
supporting information, p. 650 - 654 (2017/12/26)
The Suzuki-Miyaura (SM) cross-coupling is the most broadly utilized Pd-catalyzed C-C bond-forming reaction in the chemical industry. A large proportion of SM couplings employ dipolar aprotic solvents; however, current sustainability initiatives and increasingly stringent regulations advocate the use of alternatives that exhibit more desirable properties. Here we describe the scope and utility of the bio-derived solvent Cyrene in SM cross-couplings and evaluate its suitability as a reaction medium for this benchmark transformation from discovery to gram scale.
Pd-catalyzed cross-coupling reactions with carbonyls: Application in a very efficient synthesis of 4-aryltetrahydropyridines
Barluenga, Jose,Tomas-Gamasa, Maria,Moriel, Patricia,Aznar, Fernando,Valdes, Carlos
supporting information; experimental part, p. 4792 - 4795 (2009/05/07)
A method is proposed to prepare 4-aryltetrahydropyridines by a Pd-catalyzed cross-coupling reaction by using tosylhydrazone as the nucleophilic coupling agent without stoichiometric organometallic reagent. Palladium-catalyzed couplings can be used for the formation of C-C linkages. It was observed during study that tosylhydrazone can be generated by employing 4-piperidones directly in the cross-coupling reaction with tetrahydropyridines in very high yields. It was also found during study that the ketones and aldehydes can be employed as nucleophilic coupling partners in a reaction without using stoichiometric organometallic reagent. The study concluded that the method can be used to prepare different types of di- and trisubstituted olefins at large scale.
Trans-Selective Olefination of Carbonyl Compounds by Low-Valent Titanium-Mediated Dehydroxybenzotriazolylation
Katritzky, Alan R.,Cheng, Dai,Henderson, Scott A.,Li, Jianqing
, p. 6704 - 6709 (2007/10/03)
Lithiation with n-butyllithium of a variety of benzotriazole derivatives 1a-f and 5a-d, all containing a proton α to the benzotriazolyl moiety, gave anions which underwent addition to aliphatic, aromatic, and α,β-unsaturated aldehydes and cyclic and acyclic ketones. The resultant N-(β-hydroxyalkyl)benzotriazole derivatives 3a-m, 6a-g, 9a-d, and 10a were dehydroxybenzotriazolylated when treated with low-valent titanium to give alkenes 4a-m, dienes 7a- j, and triene 11a, with selectivity for the trans isomers without separation of diastereoisomeric intermediates. This method offers an alternative to the three most frequently used methods for the formation of alkenes from carbonyl compounds-the Wittig, Peterson, and Julia reactions-especially in the formation of tri- and tetrasubstituted alkenes.
Cyclization of α,ω-diborylalkanes via double Suzuki-Miyaura coupling
Soderquist, John A.,Leon, Gisela,Colberg, Juan C.,Martinez, Isamir
, p. 3119 - 3122 (2007/10/02)
Both carbo- and heterocyclic six-membered ring systems (3) containing an exocyclic carbon-carbon double bond have been prepared (25-76%) from α,ω-dienes (1) through the cross coupling of their dihydroboration products (2) with either aromatic or aliphatic vinylidene dibromides (4) in a one-pot Pd-catalyzed sequence.
Photolysis of 1,1,1-Triarylalkane. A New Photochemical Carbene Generation Process
Shi, Min,Okamoto, Yoshiki,Takamuku, Setsuo
, p. 3821 - 3824 (2007/10/02)
Upon UV irradiation in methanol some 1,1,1-triarylalkanes underwent an α,α-elimination of two aryl groups to give biaryls and the corresponding carbene intermediates, which inserted into the OH bond of the methanol to afford methyl ethers and/or underwent a 1,2-H shift to afford olefins.Furthermore, the efficieny of this elimination was highly dependent upon the bulkiness of the alkyl groups.
