4265-25-2Relevant academic research and scientific papers
Enantio- and Diastereoselective, Complete Hydrogenation of Benzofurans by Cascade Catalysis
Gallagher, Timothy,Glorius, Frank,Hu, Tianjiao,Moock, Daniel,Wagener, Tobias
supporting information, p. 13677 - 13681 (2021/05/10)
We report an enantio- and diastereoselective, complete hydrogenation of multiply substituted benzofurans in a one-pot cascade catalysis. The developed protocol facilitates the controlled installation of up to six new defined stereocenters and produces architecturally complex octahydrobenzofurans, prevalent in many bioactive molecules. A unique match of a chiral homogeneous ruthenium-N-heterocyclic carbene complex and an in situ activated rhodium catalyst from a complex precursor act in sequence to enable the presented process.
Synthesis of Chiral Polycyclic Tetrahydrocarbazoles by Enantioselective Aminocatalytic Double Activation of 2-Hydroxycinnamaldehydes with Dienals
Ming, Yong-Chao,Lv, Xue-Jiao,Liu, Ming,Liu, Yan-Kai
supporting information, p. 6515 - 6519 (2021/09/02)
An efficient aminocatalytic enantioselective double-activation strategy has been developed that combines several different aminocatalytic modes in a cascade process, such as iminium ion, vinylogous iminium ion, trienamine, and dienamine activations. By using this strategy, 2-hydroxycinnamaldehydes worked well with various dienals via [4 + 2] cycloaddition and the oxa-Michael reaction-initiated cascade, respectively, leading to chiral polycyclic tetrahydrocarbazole and chromane derivatives with excellent diastereo- and enantioselectivities.
Highly Efficient Synthesis of 2-Substituted Benzo[ b ]furan Derivatives from the Cross-Coupling Reactions of 2-Halobenzo[ b ]furans with Organoalane Reagents
Wen, Chang,Wu, Chuan,Luo, Ruiqiang,Li, Qinghan,Chen, Feng
, p. 3847 - 3861 (2021/07/02)
A highly efficient and simple route for the synthesis of 2-substituted benzo[ b ]furans has been developed by palladium-catalyzed cross-coupling reaction of 2-halobenzo[ b ]furans with aryl, alkynyl, and alkylaluminum reagents. Various 2-aryl-, 2-alkynyl-, and 2-alkyl-substituted benzo[ b ]furan derivatives can be obtained in 23-97% isolated yields using 2-3 mol% PdCl 2/4-6 mol% XantPhos as the catalyst under mild reaction conditions. The aryls bearing electron-donating or electron-withdrawing groups in 2-halobenzo[ b ]furans gave products in 40-97% isolated yields. In addition, aluminum reagents containing thienyl, furanyl, trimethylsilanyl, and benzyl groups worked efficiently with 2-halobenzo[ b ]furans as well, and three bioactive molecules with 2-substituted benzo[ b ]furan skeleton were synthesized. Furthermore, the broad substrates scope and the typical maintenance of vigorous efficiency on gram scale make this protocol a potentially practical method to synthesize 2-substituted benzo[ b ]furan derivatives. On the basis of the experimental results, a possible catalytic cycle has been proposed.
A methylation platform of unconventional inert aryl electrophiles: Trimethylboroxine as a universal methylating reagent
Feng, Boya,Yang, Yudong,You, Jingsong
, p. 6031 - 6035 (2020/07/10)
Methylation is one of the most fundamental conversions in medicinal and material chemistry. Extension of substrate types from aromatic halides to other unconventional aromatic electrophiles is a highly important yet challenging task in catalytic methylation. Disclosed herein is a series of transition metal-catalyzed methylations of unconventional inert aryl electrophiles using trimethylboroxine (TMB) as the methylating reagent. This transformation features a broad substrate type, including nitroarenes, benzoic amides, benzoic esters, aryl cyanides, phenol ethers, aryl pivalates and aryl fluorides. Another important merit of this work is that these widespread "inert"functionalities are capable of serving as directing or activating groups for selective functionalization of aromatic rings before methylation, which greatly expands the connotation of methylation chemistry.
A light triggered optical and chiroptical switch based on a homochiral Eu2L3helicate
Cheng, Zhenyu,Gao, Ting,Li, Hongfeng,Yan, Pengfei,Yao, Yuan,Zhang, Jianpeng,Zhou, Yanyan
, p. 6788 - 6796 (2020/06/03)
Optical and chiroptical photoswitches have found potential applications in advanced information technologies. Herein, a pair of chiral triple-stranded helicates [Eu2(o-LRR)3](TOf)6and [Eu2(o-LSS)3](TOf)6, which have chirality, luminescence and light stimuli-responsive properties, have been designed and synthesized. The ligands o-LRR/SSare composed of photochromic diarylethene moieties as spacers and two chiral 2,6-dipicolinic amides as coordination units. Through the comprehensive spectral characteristics in combination with semiempirical geometry optimization using the Sparkle/RM1 model, it was confirmed that (R/S)-1-phenylethanamines decorated at the terminals of ligands successfully controlled the stereoselective self-assembly of the helicates. Upon alternating UV and visible light irradiation, the diarylethene experienced a reversible change between a colorless open-ring state and a pink closed-ring state. This photochromic process caused variations in the electronic structure and ligand conformation, and led to the presence of light-responsive optical (UV and PL) and chiroptical (ECD and CPL) switching properties. The helicate may, therefore, be considered as a completely reversible +/- ECD and on/off CPL switch. Furthermore, on the basis of these light-switchable optical properties, the INHIBIT and IMPLICATION logic gates were fabricated.
Rhodium-Catalyzed Intermolecular Cyclopropanation of Benzofurans, Indoles, and Alkenes via Cyclopropene Ring Opening
Jeyaseelan, Rubaishan,Lautens, Mark,Ross, Rachel J.
supporting information, (2020/06/29)
The generation of metal carbenoids via ring opening of cyclopropenes by transition metals offers a simple entry into highly reactive intermediates. Herein, we describe a diastereoselective intermolecular rhodium-catalyzed cyclopropanation of heterocycles and alkenes using cyclopropenes as carbene precursors with a low loading of a commercially available rhodium catalyst. The reported method is scalable and could be performed with catalyst loadings as low as 0.2 mol %, with no impact to the reaction yield or selectivity.
Discovery of orthogonal synthesis using artificial intelligence: Pd(OAc)2-catalyzed one-pot synthesis of benzofuran and bicyclo[3.3.1]nonane scaffolds
Takabatake, Tetsuhiko,Fujiwara, Keisuke,Okamoto, Sho,Kishimoto, Ryo,Kagawa, Natsuko,Toyota, Masahiro
, (2020/08/10)
A synthetic route for the common intermediate, methyl 2-formylbenzofuran-7-carboxylate (7a), to efficiently assemble three bioactive benzofurans 4–6 was explored using the artificial intelligence system SYNSUP. Among the routes proposed by SYNSUP, we investigated a three-step synthesis of 7a using methyl 4-ally-3-oxohept-6-enoate (10). A new catalytic reaction was found in which 7a was directly obtained from 10 in a single step with a yield of 24percent. It was found that this chemical yield could be increased to 74percent when methyl 3-allyl-2-hydroxybenzoate (9a), an intermediate of the above one-pot transformation, was subjected to the catalytic process. In addition, in this catalytic process, 8a (76percent) and 11 (77percent) were each selectively synthesized from 10 by changing only the solvent. Therefore, we created a novel orthogonal synthesis of methyl 2-methylbenzofuran-7-carboxylate (8a) and methyl 9-oxobicyclo[3.3.1]nona-3,6-diene-1-carboxylate (11). Finally, the total syntheses of bioactive benzofurans 4–6 were completed smoothly using 7a and 8a.
Catalytic Wacker-type Oxidations Using Visible Light Photoredox Catalysis
Ho, Yee Ann,Paffenholz, Eva,Kim, Hyun Jin,Orgis, Benjamin,Rueping, Magnus,Fabry, David C.
, p. 1889 - 1892 (2019/03/17)
A combined palladium/photoredox catalytic system for the efficient oxidation of terminal olefins to the corresponding methyl ketones is presented. The interplay of air, water, and light leads to a protocol in which the stoichiometric oxidants required for oxidative palladium catalysis are substituted with catalytic, single-electron transfer processes. Detailed mechanistic investigations revealed the role of the key components, in situ generated species, and catalysts. A broad range of substrates was examined in homogeneous as well as heterogeneous photoredox protocols, delivering the desired products in good yields.
Pd-catalyzed intramolecular Heck reaction for the synthesis of 2-methylbenzofurans
Zhou,Shi, Yuxing,Zhu, Xueyan,Zhang, Peng
, p. 2005 - 2008 (2019/07/03)
A new strategy for the synthesis of 2-Methylbenzofurans via the intramolecular Heck reaction has been developed. This efficient palladium-catalyzed system showed good catalytic activity. Various substituted 2-methylbenzofurans could be afforded in good to excellent yields.
A 2 - substituted benzofuran compound of the catalytic synthesis method
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Paragraph 0010; 0011; 0012, (2019/05/22)
The invention discloses a 2 - substituted benzofuran compound of the catalytic synthesis method, comprises the following steps: normal temperature and pressure, the 2 - alkynyl substituted phenol dissolved in acetonitrile, wherein the 2 - alkynyl substituted phenol with acetonitrile molar volume ratio of 1: 1mmol/mL, to obtain 2 - alkynyl substituted phenol acetonitrile solution; and then to the acetonitrile solution in adding cuprous chloride and cesium carbonate, wherein the cuprous chloride and cesium carbonate of respectively the molar consumption of 2 - alkynyl-substituted phenol mole amount of 5%; after, room temperature stirring 6 hours, produced by the reaction of 2 - substituted benzofuran compound. The invention 2 - substituted benzofuran compound of the catalytic method for synthesis of low cost, high yield, its preparation 1 g of 2 - substituted benzofuran compounds required the cost of the catalyst the prior by iridium catalyst is a catalyst of the synthetic method has lowered 2 orders of magnitude, to improve the yield of the 88.5 - 95.8%.
