Selenophene-containing heterotriacenes by a C–Se coupling/cyclization reaction

• Pierre-Olivier Schwartz,
• Sebastian Förtsch,
• Astrid Vogt,
• Elena Mena-Osteritz and
• Peter Bäuerle

Beilstein J. Org. Chem. 2019, 15, 1379–1393, doi:10.3762/bjoc.15.138

• preparation, efficient multistep synthesis routes with good overall yields based on recently published transition metal-catalyzed C–S and C–Se coupling/cyclization reactions in the crucial cyclization steps of iodinated bithiophene and biselenophene precursors. Heterotriacenes 1–4 turned out to be stable and

Steroid diversification by multicomponent reactions

• Leslie Reguera,
• Cecilia I. Attorresi,
• Javier A. Ramírez and
• Daniel G. Rivera

Beilstein J. Org. Chem. 2019, 15, 1236–1256, doi:10.3762/bjoc.15.121

• -secocholestan-5-ol 33 in such a metal-catalyzed MCR led to the steroidal chroman-ketal 34 as a mixture of epimers at the center bearing the methoxy group, instead of the expected chroman spiroketal. The authors proposed the initial formation of a 6-membered enol ether, which may subsequently undergo either a

A three-component, Zn(OTf)₂-mediated entry into trisubstituted 2-aminoimidazoles

• Alexei Lukin,
• Anna Bakholdina,
• Anna Kryukova,
• Alexander Sapegin and
• Mikhail Krasavin

Beilstein J. Org. Chem. 2019, 15, 1061–1064, doi:10.3762/bjoc.15.103

• which makes it a useful tool for library array synthesis. The investigation of other metal-catalyzed transformations of propargylureas is underway in our laboratories and will be reported in due course. Examples of imidazole (1 and 2) and oxazole (3) syntheses from propargylamides previously reported

An efficient synthesis of the guaiane sesquiterpene (−)-isoguaiene by domino metathesis

• Yuzhou Wang,
• Ahmed F. Darweesh,
• Patrick Zimdars and
• Peter Metz

Beilstein J. Org. Chem. 2019, 15, 858–862, doi:10.3762/bjoc.15.83

• were interested in developing an efficient synthetic access to 1 using a combined organocatalytic/metal-catalyzed strategy related to the one applied to the preparation of 2 [7][8]. Results and Discussion As illustrated in Scheme 1, two alternative routes were retrosynthetically devised, both of which

Synthesis of acylglycerol derivatives by mechanochemistry

• Karen J. Ardila-Fierro,
• Andrij Pich,
• Marc Spehr,
• José G. Hernández and
• Carsten Bolm

Beilstein J. Org. Chem. 2019, 15, 811–817, doi:10.3762/bjoc.15.78

• molecules under environments of high mechanical stress. Specifically, the synthesis of mono- and diacylglycerols required first, the application of solventless functional group protection chemistry in ball mills, second, the implementation of metal-catalyzed epoxide-ring opening, and third, the development

Synthesis of 2H-furo[2,3-c]pyrazole ring systems through silver(I) ion-mediated ring-closure reaction

• Vaida Milišiūnaitė,
• Rūta Paulavičiūtė,
• Eglė Arbačiauskienė,
• Vytas Martynaitis,
• Wolfgang Holzer and
• Algirdas Šačkus

Beilstein J. Org. Chem. 2019, 15, 679–684, doi:10.3762/bjoc.15.62

• derivatives of the aromatic 2H-furo[2,3-c]pyrazole ring system is still quite limited, and their chemistry and functional properties remain largely underexplored. The current study investigates routes to construct this system from easily accessible starting materials using metal-catalyzed reactions. A simple

The LANCA three-component reaction to highly substituted β-ketoenamides – versatile intermediates for the synthesis of functionalized pyridine, pyrimidine, oxazole and quinoxaline derivatives

• Tilman Lechel,
• Roopender Kumar,
• Mrinal K. Bera,
• Reinhold Zimmer and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2019, 15, 655–678, doi:10.3762/bjoc.15.61

• into a 1-nonafluorobutanesulfonate group is presented, that – like the closely related triflate group – allows transition metal-catalyzed coupling reactions or nucleophilic substitutions [52]. The selected three examples presented in Scheme 13 show striking differences in the deprotection step [33

Intramolecular cascade annulation triggered by rhodium(III)-catalyzed sequential C(sp²)–H activation and C(sp³)–H amination

• Liangliang Song,
• Guilong Tian,
• Johan Van der Eycken and
• Erik V. Van der Eycken

Beilstein J. Org. Chem. 2019, 15, 571–576, doi:10.3762/bjoc.15.52

• activation; rhodium; acrylamide; heterocycles; Introduction Over the last decade, transition metal-catalyzed C(sp2)–H activation has emerged as an efficient strategy to access complex molecules [1][2][3][4][5][6]. Among the methodologies, RhIII-catalyzed oxidative annulation of a C(sp2)–H bond with 2π

Selectivity in multiple multicomponent reactions: types and synthetic applications

• Ouldouz Ghashghaei,
• Francesca Seghetti and
• Rodolfo Lavilla

Beilstein J. Org. Chem. 2019, 15, 521–534, doi:10.3762/bjoc.15.46

• connected through long linear alkyl chains. Representative examples include polymerizations using Biginelli [12], Passerini [13], Ugi [14], metal-catalyzed MCRs [15], and reactive combinations involving an alkyne-sulfonyl azide nucleophile [16] and sulfur, amines and isocyanides [17] (Scheme 3). An

• ; V) generation of new functional groups; VI) polymerization; VII) macrocyclization; FG = functional group. Indiscriminate double Ugi MCR upon pyridine-2,6-dicarboxylic acid. Representative examples of MCR-polymer synthesis. A) Biginelli HTS of polymers; B) Passerini;- C) Ugi-; D) metal-catalyzed MCR

A novel and efficient synthesis of phenanthrene derivatives via palladium/norbornadiene-catalyzed domino one-pot reaction

• Yue Zhong,
• Wen-Yu Wu,
• Shao-Peng Yu,
• Tian-Yuan Fan,
• Hai-Tao Yu,
• Nian-Guang Li,
• Zhi-Hao Shi,
• Yu-Ping Tang and
• Jin-Ao Duan

Beilstein J. Org. Chem. 2019, 15, 291–298, doi:10.3762/bjoc.15.26

• , trifluoromethyl and ester, gave 75–95% yields of the corresponding products y-9–y-13, which were precursors for further transition metal-catalyzed cross-coupling reactions. To further explore the generality of this reaction, different substituted ortho-bromobenzoyl chlorides were then tested (Scheme 3). The ortho

Synthesis of 1,2-divinylcyclopropanes by metal-catalyzed cyclopropanation of 1,3-dienes with cyclopropenes as vinyl carbene precursors

• Jesús González,
• Alba de la Fuente,
• María J. González,
• Laura Díez de Tejada,
• Luis A. López and
• Rubén Vicente

Beilstein J. Org. Chem. 2019, 15, 285–290, doi:10.3762/bjoc.15.25

Metal-free C–H mercaptalization of benzothiazoles and benzoxazoles using 1,3-propanedithiol as thiol source

• Yan Xiao,
• Bing Jing,
• Xiaoxia Liu,
• Hongyu Xue and
• Yajun Liu

Beilstein J. Org. Chem. 2019, 15, 279–284, doi:10.3762/bjoc.15.24

• activity against Candida albicans and Candida tropicalis [8] and 2-mercapto-1,3-benzothiol and its derivatives exhibit inhibitory effects against thyroid peroxidase [9]. (Hetero)aryl thiols are often prepared from the corresponding halides through direct nucleophilic substitution [10][11][12] or metal

• -catalyzed C–S coupling reactions [13]. Conventional methods for the synthesis of 2-mercaptobenzoxazoles and 2-mercaptobenzothiazoles include the interaction of 2-aminophenol or 2-haloanilines with carbon disulfide [14][15][16], or potassium ethyl xanthate [17][18] (Scheme 1). In 2017, the Dong group

• [22] and 1,2-ethanedithiol [23]. In the past decades, C–H functionalization has become an effective strategy for constructing different molecules directly from simple arenes and alkanes. C–H functionalization is an important method for C–S coupling reactions [24][25]. For example, transition metal

Gold-catalyzed ethylene cyclopropanation

• Silvia G. Rull,
• Andrea Olmos and
• Pedro J. Pérez

Beilstein J. Org. Chem. 2019, 15, 67–71, doi:10.3762/bjoc.15.7

• transfer; cyclopropane; cyclopropylcarboxylate; ethylene cyclopropanation; ethyl diazoacetate; gold catalysis; Introduction Nowadays the olefin cyclopropanation through metal-catalyzed carbene transfer starting from diazo compounds to give olefins constitutes a well-developed tool (Scheme 1a), with an

• standard. Effect of the pressure of ethylene on the yields of ethyl cyclopropanecarboxylate in the reaction of ethylene and EDA catalyzed by IPrAuCl/NaBArF4. (a) General metal-catalyzed olefin cyclopropanation reaction with diazo compounds. (b) The ethylene cyclopropanation with diazoacetates leads to

Ruthenium-based olefin metathesis catalysts with monodentate unsymmetrical NHC ligands

• Veronica Paradiso,
• Chiara Costabile and
• Fabia Grisi

Beilstein J. Org. Chem. 2018, 14, 3122–3149, doi:10.3762/bjoc.14.292

• to the current state of research are discussed. Keywords: ligand design; olefin metathesis; ruthenium catalysts; selectivity; unsymmetrical N-heterocyclic carbenes; Introduction The transition metal-catalyzed olefin metathesis reaction is an indispensable synthetic tool for the construction of new

Ring-closing-metathesis-based synthesis of annellated coumarins from 8-allylcoumarins

• Christiane Schultze and
• Bernd Schmidt

Beilstein J. Org. Chem. 2018, 14, 2991–2998, doi:10.3762/bjoc.14.278

• these established methods necessary. Examples from the past 15 years include transition metal-catalyzed transformations [21][22][23], solid-phase synthesis directed at combinatorial library design [24] and organocatalytic annellation reactions [25][26]. Sparked by our interest in the development and

Molecular iodine-catalyzed one-pot multicomponent synthesis of 5-amino-4-(arylselanyl)-1H-pyrazoles

• Camila S. Pires,
• Daniela H. de Oliveira,
• Maria R. B. Pontel,
• Jean C. Kazmierczak,
• Roberta Cargnelutti,
• Diego Alves,
• Raquel G. Jacob and
• Ricardo F. Schumacher

Beilstein J. Org. Chem. 2018, 14, 2789–2798, doi:10.3762/bjoc.14.256

• methodologies describing the transition metal-catalyzed cross-coupling reaction of diorganyl diselenides with (hetero)aryl, alkenyl, and alkynyl halides or pseudo-halides [3], an updated protocol that describe reduced waste generation and atom-economy is desired. In this context, the multicomponent cyclization

Copolymerization of epoxides with cyclic anhydrides catalyzed by dinuclear cobalt complexes

• Yo Hiranoi and
• Koji Nakano

Beilstein J. Org. Chem. 2018, 14, 2779–2788, doi:10.3762/bjoc.14.255

• metal-catalyzed PO/PA copolymerization [41]. As there were no detectable signal for ether linkages in the 1H NMR spectra of the obtained copolymers, the resulting copolymers possess a completely alternating structure. The regioselectivity in the ring-opening of PO was estimated by analyzing the

Transition metal-free oxidative and deoxygenative C–H/C–Li cross-couplings of 2H-imidazole 1-oxides with carboranyl lithium as an efficient synthetic approach to azaheterocyclic carboranes

• Lidia A. Smyshliaeva,
• Mikhail V. Varaksin,
• Pavel A. Slepukhin,
• Oleg N. Chupakhin and
• Valery N. Charushin

Beilstein J. Org. Chem. 2018, 14, 2618–2626, doi:10.3762/bjoc.14.240

• metal-catalyzed C–Br/C–M (M = Li, Mg, Zn, etc.) and C–Br/C–H cross-couplings reactions leading to more complex organic compounds. Mono-substituted imidazolyl carboranes 4a–d and their N-oxide analogues 5a–d were characterized by the data of elemental analysis, IR, NMR spectroscopy (1H, 13C{1H} (APT

Gold-catalyzed post-Ugi alkyne hydroarylation for the synthesis of 2-quinolones

• Xiaochen Du,
• Jianjun Huang,
• Anton A. Nechaev,
• Ruwei Yao,
• Jing Gong,
• Erik V. Van der Eycken,
• Olga P. Pereshivko and
• Vsevolod A. Peshkov

Beilstein J. Org. Chem. 2018, 14, 2572–2579, doi:10.3762/bjoc.14.234

• functionalization [25][26][27][28][29] of the 2-quinolone scaffold has become a budding research trend. In the last decade, a great number of efficient approaches has been developed utilizing transition metal-catalyzed [30][31][32], Lewis acid-mediated [33], and radical cyclizations [34] of various aniline

• derivatives with most recent strategies focusing on the implementation of transition metal-catalyzed C–H activation methods [35][36]. One of the common approaches towards 2-quinolones 2 involves the intramolecular Friedel–Crafts hydroarylation [37][38] of N-arylamides of 3-substituted propynoic acids 1

Synthesis of aryl sulfides via radical–radical cross coupling of electron-rich arenes using visible light photoredox catalysis

• Amrita Das,
• Mitasree Maity,
• Simon Malcherek,
• Burkhard König and
• Julia Rehbein

Beilstein J. Org. Chem. 2018, 14, 2520–2528, doi:10.3762/bjoc.14.228

• , antidepressant or antileukotriene agents (Figure 1). Three of the five most selling drugs in 2015 were organosulfur compounds. The majority of methods for C–S bond synthesis use transition metal-catalyzed cross coupling of thiols and their derivatives with organohalides [4][5][6], arylboronic acids [7], aryl

Synergistic approach to polycycles through Suzuki–Miyaura cross coupling and metathesis as key steps

• Sambasivarao Kotha,
• Milind Meshram and
• Chandravathi Chakkapalli

Beilstein J. Org. Chem. 2018, 14, 2468–2481, doi:10.3762/bjoc.14.223

• -Doctoral Fellow at the KU Leuven, Belgium under the EMINTE programme. During post-doctoral work his research work was related to organic synthesis under microwave reaction conditions. Presently, he is Research Associate with Prof. S. Kotha. His research interests include various transition-metal-catalyzed

Cobalt- and rhodium-catalyzed carboxylation using carbon dioxide as the C1 source

• Tetsuaki Fujihara and
• Yasushi Tsuji

Beilstein J. Org. Chem. 2018, 14, 2435–2460, doi:10.3762/bjoc.14.221

• reagents in transition-metal-catalyzed C–C bond-forming reactions [21][22][23]. In particular, the carboxylation of allyl esters with CO2 has been catalyzed by Pd or Ni under electrochemical reaction conditions [24][25]. For catalytic reactions using reducing agents, Martin reported Ni-catalyzed

• useful methods such as the transition-metal-catalyzed carbozincation of alkynes that affords stereodefined alkenylzinc compounds have been developed. To date, a variety of organozinc reagents (RZnX and R2Zn: R = aryl, alkyl, alkenyl, alkynyl, allyl, and benzyl groups) have been used in these reactions

• ). Possibly another ligand exchange between E and KOAc regenerates the Rh complex A (step e). The desired product (35) is obtained after lactonization. Hydrocarboxylation of arylalkenes Hydrocarboxylation is an essential carboxylation reaction. To date, transition-metal-catalyzed hydrocarboxylation reactions

Efficient catalytic alkyne metathesis with a fluoroalkoxy-supported ditungsten(III) complex

• Henrike Ehrhorn,
• Janin Schlösser,
• Dirk Bockfeld and
• Matthias Tamm

Beilstein J. Org. Chem. 2018, 14, 2425–2434, doi:10.3762/bjoc.14.220

• progress in the past decades [1][2][3][4][5], the synthetic potential of alkyne metathesis has been growing only recently [6][7][8][9][10][11]. Alkyne metathesis represents a transition-metal-catalyzed transformation in which carbon–carbon triple bonds are cleaved and formed under mild conditions via

Catalyst-free synthesis of 4-acyl-NH-1,2,3-triazoles by water-mediated cycloaddition reactions of enaminones and tosyl azide

• Lu Yang,
• Yuwei Wu,
• Yiming Yang,
• Chengping Wen and
• Jie-Ping Wan

Beilstein J. Org. Chem. 2018, 14, 2348–2353, doi:10.3762/bjoc.14.210

• is a heterocyclic moiety showing exceptionally broad and important applications as privileged structure in the discovery of biologically functional scaffolds, organic materials preparation, as directing group in transition-metal-catalyzed transformations and as key building block in the synthesis of

• ][30][31][32], for example, has served enormously to the advances in both the preparation and application of 1,2,3-triazoles. In addition, the discovery of other metal-catalyzed alkyne–azide cycloadditions (MAAC) providing 1,2,3-triazoles with diverse substitution patterns triggers the continuous

• development of these metal-catalyzed cycloaddition strategies [33][34][35]. Alongside the vast progress happened in MAAC-based 1,2,3-triazole synthesis, the past decade has witnessed the emergence of another powerful cycloaddition tool for the 1,2,3-triazole synthesis: the metal-free cycloaddition of azides

Hydroarylations by cobalt-catalyzed C–H activation

• Rajagopal Santhoshkumar and
• Chien-Hong Cheng

Beilstein J. Org. Chem. 2018, 14, 2266–2288, doi:10.3762/bjoc.14.202

• synthesis owing to the necessity of green chemistry for the modern universe [1][2][3]. In this context, catalytic C–H functionalization has been acknowledged as an atom- and step-economical process [4][5][6]. A wide range of transition metal-catalyzed non-directed or directing group assisted C–H activation

• -catalyzed hydroarylation of C=X bonds Transition-metal-catalyzed addition of C–H bond to polar π bonds such as imines, isocyanates and carbonyls is one of the efficient methods to incorporate heteroatoms in organic molecules [45]. Yoshikai et al. developed an addition reaction of arylpyridines 3 to imines

• traditional synthetic methods to construct new C−C bonds. Among the first-row transition metals, both low- and high-valent cobalt catalysts have played a substantial role in these hydroarylation reactions providing an economical alternative to the precious metal-catalyzed reactions and also showed distinct