Article
Chemistry, Organic
Lan Zhao, Changfu Qiu, Lixin Zhao, Guangwei Yin, Fangyi Li, Chunhua Wang, Zheng Li
Summary: Described is an efficient method for the synthesis of 1H- and 3H-indoles, which does not require the use of transition metal or stoichiometric amount of oxidant. The process is operationally simple, easily scalable, and exhibits good substrate tolerability. Control experiments suggest the reactions may proceed in a tandem sequence of bromination and intramolecular Friedel-Crafts alkylation in a one-pot procedure.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2021)
Article
Chemistry, Applied
Zhen Deng, Liu-Yan Qiu, Jie Chen, Hui Zhang, Weiguo Cao, Xiao-Jun Tang
Summary: The Cu-mediated N-H trifluoroethylation of NH-containing heteroaromatic compounds with CF3CHCl2 (HCFC-123) has been achieved, which is commercially available in industrial scale. This method is applicable to various NH-containing heteroaromatic compounds, including indoles, pyrroles, pyrazoles, and carbazoles. Moreover, this protocol enables the late-stage trifluoroethylation of NH-containing heteroaromatic bioactive molecules.
ADVANCED SYNTHESIS & CATALYSIS
(2023)
Article
Chemistry, Organic
Dmytro M. Khomenko, Roman O. Doroshchuk, Hanna Ivanova, Borys Zakharchenko, Ilona Raspertova, Oleksandr V. Vaschenko, Sergiu Shova, Alexey Dobrydnev, Yurii S. Moroz, Oleksandr O. Grygorenko, Rostyslav D. Lampeka
Summary: A series of compounds, including 2-(1H-1,2,4-triazol-3-yl)acetates and different substituted 5-amino-2,4-dihydro-3H-pyrazol-3-ones, were synthesized using the Pinner reaction strategy. The scope and limitations of the synthesis method have been established.
TETRAHEDRON LETTERS
(2021)
Article
Chemistry, Multidisciplinary
Maximilian Scheruebl, Constantin G. Daniliuc, Armido Studer
Summary: The article introduces the application of arynes as radical acceptors, showing how the stable radical TEMPO can react with different ortho-substituted benzynes to generate aryl radicals for subsequent cyclizations, eventually being trapped by TEMPO. This method provides a novel approach for the convenient synthesis of various dihydrobenzofurans, oxindoles, and sultones.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Biochemistry & Molecular Biology
Manar M. Arafeh, Ebrahim Saeedian Moghadam, Sirin A. I. Adham, Raphael Stoll, Raid J. Abdel-Jalil
Summary: A novel series of 2-(aryldiazenyl)-3-methyl-1H-benzo[g]indole derivatives were synthesized using polyphosphoric acid as a cyclizing agent. The compounds were characterized and evaluated for cytotoxic activity, with two of them showing significant cytotoxicity and selectivity after dose screening.
Article
Chemistry, Multidisciplinary
Quentin Dherbassy, Srimanta Manna, Chunling Shi, Watcharapon Prasitwatcharakorn, Giacomo E. M. Crisenza, Gregory J. P. Perry, David J. Procter
Summary: In this study, an enantioselective copper-catalyzed borylative cyclization was reported for the assembly of privileged pyrroloquinazolinone motifs. The reaction demonstrated high enantio- and diastereocontrol, yielding products with quaternary stereocenters. The utility of the products was further demonstrated through additional manipulations.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Applied
Bartosz Bisek, Wojciech Chaladaj
Summary: This study describes the Pd-catalyzed tandem cyclization/coupling of internal β-propargylic β-ketoesters with (hetero)aryl bromides. Two protocols are established to selectively produce either 2-benzylidene-dihydrofurans or 2-benzyl-furans. The proposed catalytic cycle involves oxidative addition, substitution of bromide with alkyne, rate-limiting anti-selective 5-exo-dig oxocyclization, deprotonation of the oxonium intermediate, and reductive elimination.
ADVANCED SYNTHESIS & CATALYSIS
(2022)
Article
Chemistry, Organic
Alla I. Vaskevych, Nataliia O. Savinchuk, Ruslan I. Vaskevych, Svitlana V. Shishkina, Mykhailo V. Vovk
Summary: 2-butenylquinazolin-4(3H)-ones can undergo intramolecular aza-Wacker cyclization to form methylene-substituted pyrrolo(pyrido)[2,1-b]quinazolinones when treated with the catalytic system Pd(OAc)(2)/PPh3/Cs2CO3/benzoquinone in dioxane or Pd(PPh3)(2)Cl-2/t-BuONa/Cs2CO3/benzoquinone in toluene. The latter catalytic system also reacts with pentenyl(hexenyl)quinazolin-4(3H)-ones, but leads to the formation of vinyl-substituted pyrrolo(pyrido)[2,1-b]quinazolinones via competition between aminopalladation of C-H multiple bonds and allylic C(sp(3))-H bond activation.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2023)
Article
Chemistry, Organic
Huan Wang, Ying Xie, Yulong Li, Yi Yang, Jilan Long, Hao Zhang
Summary: A copper-catalyzed cascade synthesis of substituted 2-aryl-1H-indoles from phenols and oximes is developed, involving dual C-H bond cleavage of phenols and cyclization with oximes. The reaction proceeds smoothly under mild conditions without any additives.
ASIAN JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Organic
Jin-Chen Li, Bing-Xia Yan, Gang Wang, Zhi-Shi Ye
Summary: Here, we demonstrated an efficient cascade reaction of N-tosyl ortho-alkynylanilines and N-acyl ortho-alkynylanilines using Rh(COD)(2)BF4/( t )BuXantPhos as a catalyst. The reaction exhibited excellent chemoselectivity and regioselectivity, high atom-economy, and wide substrate scope. Mechanistic studies revealed that the success of this reaction relied on the strong capability of the rhodium catalyst to recognize the N-substituent group in the selective nucleophilic cyclization and alkyne insertion.
Article
Chemistry, Organic
Lona Dutta, Anwita Chattopadhyay, Nisha Yadav, S. S. V. Ramasastry
Summary: This study presents a metal-free strategy for the synthesis of various alpha-arylidene cyclopenta[b]indoles by phosphine-catalysed (3 + 2) annulation of alpha,beta-ynones and 3-nitroindoles. The rearomatisation of the indole nucleus was observed for the first time during this annulative transformation. The method was also applied to the synthesis of an antimalarial natural product, bruceolline E.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2023)
Article
Chemistry, Organic
Yinrong Wu, Kangmei Wen, Jiewen Chen, Jie Shi, Xingang Yao, Xiaodong Tang
Summary: A copper-mediated decarboxylative coupling reaction between arylacetic acids and 1,3-dicarbonyl compounds was described, leading to the formation of methanocycloocta[b]indoles in some cases through sequential intramolecular dehydrocyclization process. The protocol offers a broad substrate scope, easy operation, and good yields, with the resulting products showing potent antiproliferative activity against human cancer cell lines in MTT assay.
Article
Chemistry, Organic
Camilla Loro, Julie Oble, Francesca Foschi, Marta Papis, Egle M. Beccalli, Sabrina Giofre, Giovanni Poli, Gianluigi Broggini
Summary: Treatment of O-allyl N-tosyl carbamates with aromatic compounds in the presence of Cu(OTf)(2) or TMSOTf as promoters results in the formation of N-substituted 1-arylpropan-2-amines, 1,2-diarylpropanes, 1,1-diarylpropanes, or indanes, depending on the nature of the promoter and aryl substrates. A proposed mechanism explains the outcome of these C-H based cascades, involving initial acid promoted decarboxylative/deamidative Friedel-Crafts allylation followed by protonation of the allylated arene.
ORGANIC CHEMISTRY FRONTIERS
(2022)
Article
Chemistry, Applied
Bita Manavi, Hossein Zahedian Tejeneki, Frank Rominger, Mahsa Armaghan, Walter Frank, Hamid Reza Bijanzadeh, Saeed Balalaie
Summary: This report discusses two distinctive intramolecular cyclizations of o-propargyloxy diketopiperazines achieved via a copper(I)-catalyzed reaction, offering an opportunity for the synthesis of challenging Diazabicyclics and Spiro-Diketopiperazinochromanes with high yields and exclusive diastereoselectivity.
ADVANCED SYNTHESIS & CATALYSIS
(2021)
Article
Chemistry, Organic
Matteo Faltracco, Said Ortega-Rosales, Elwin Janssen, Razvan C. Cioc, Christophe M. L. Vande Velde, Eelco Ruijter
Summary: The unexpected discovery in a seemingly trivial reaction led to the selective formation of a new carbazole product. This reaction, by carefully varying substituents, revealed a complex cascade mechanism with at least 10 elementary steps that could be directed towards different carbazole derivatives.
