Synthesis of a tricyclic lactam via Beckmann rearrangement and ring-rearrangement metathesis as key steps

• Sambasivarao Kotha,
• Ongolu Ravikumar and
• Jadab Majhi

Beilstein J. Org. Chem. 2015, 11, 1503–1508, doi:10.3762/bjoc.11.163

• -caprolactam from cyclohexanone oxime involving the BR. The activation energy for the BR is almost the same as that of the nucleophilic substitution at sp2 nitrogen. To synthesize various aza-arenes and cyclic imines, such as quinolines, aza-spiro compounds and dihydropyrroles, the intramolecular SN2-type

Pyridine-promoted dediazoniation of aryldiazonium tetrafluoroborates: Application to the synthesis of SF₅-substituted phenylboronic esters and iodobenzenes

• George Iakobson,
• Junyi Du,
• Alexandra M. Z. Slawin and
• Petr Beier

Beilstein J. Org. Chem. 2015, 11, 1494–1502, doi:10.3762/bjoc.11.162

• ][58], Lewis acid catalyzed electrophilic borylations of electron-rich arenes [59][60][61][62], and Sandmeyer-type borylation of arylamines or diazonium salts with B2pin2 [63][64][65][66][67], B2(OH)4 [68] or R2N-BH2 [69]. Several attempts were made to synthesize the SF5-phenylboronates. Patent

• -coupling reactions with varied degree of success. The most efficient cross-coupling reactions were the Heck reactions with alkenes, a biaryl homocoupling reaction, an azo coupling to electron-rich arenes, and a dediazoniation with TMSN3 in an ionic liquid medium [74][75]. An efficient borylation of

Surprisingly facile CO₂ insertion into cobalt alkoxide bonds: A theoretical investigation

• Willem K. Offermans,
• Claudia Bizzarri,
• Walter Leitner and
• Thomas E. Müller

Beilstein J. Org. Chem. 2015, 11, 1340–1351, doi:10.3762/bjoc.11.144

• cycloaddition. Direct catalytic carboxylation of aliphatic compounds and arenes by rhodium(I)– and ruthenium(II)–pincer complexes, respectively. Insertion of carbon dioxide into a metal–oxygen bond via a cyclic four-membered transition state. R is either an aliphatic or aromatic group. Facile CO2 uptake by zinc

Advances in the synthesis of functionalised pyrrolotetrathiafulvalenes

• Luke J. O’Driscoll,
• Sissel S. Andersen,
• Marta V. Solano,
• Dan Bendixen,
• Morten Jensen,
• Troels Duedal,
• Jess Lycoops,
• Cornelia van der Pol,
• Rebecca E. Sørensen,
• Karina R. Larsen,
• Kenneth Myntman,
• Christian Henriksen,
• Stinne W. Hansen and
• Jan O. Jeppesen

Beilstein J. Org. Chem. 2015, 11, 1112–1122, doi:10.3762/bjoc.11.125

• -functionalised calix[4]arenes (which can bind to electron-deficient aromatics and form charge-transfer complexes) [29]. Alternative routes to N-arylated MPTTFs proceed through N-arylated (1,3)-dithiolo[4,5-c]pyrrole-2-ones or (1,3)-dithiolo[4,5-c]pyrrole-2-thiones (i.e. analogues of 6). In some cases these can

Glycoluril–tetrathiafulvalene molecular clips: on the influence of electronic and spatial properties for binding neutral accepting guests

• Yoann Cotelle,
• Marie Hardouin-Lerouge,
• Stéphanie Legoupy,
• Olivier Alévêque,
• Eric Levillain and
• Piétrick Hudhomme

Beilstein J. Org. Chem. 2015, 11, 1023–1036, doi:10.3762/bjoc.11.115

• ]+˙ mixed-valence dimer and/or (TTF+˙)2 dimer species concerned systems for which the dimer stabilization is resulting from the close proximity of the two TTF units. That is the case for conjugated bisTTF systems [51], bisTTF-substituted calix[4]arenes [52], or supramolecular architectures such as [3

A new and convenient synthetic way to 2-substituted thieno[2,3-b]indoles

• Roman A. Irgashev,
• Arseny A. Karmatsky,
• Gennady L. Rusinov and
• Valery N. Charushin

Beilstein J. Org. Chem. 2015, 11, 1000–1007, doi:10.3762/bjoc.11.112

• , 620002, Russia 10.3762/bjoc.11.112 Abstract A short and robust approach for the synthesis of 2-(hetero)aryl substituted thieno[2,3-b]indoles from easily available 1-alkylisatins and acetylated (hetero)arenes has been advanced. The two-step procedure includes the “aldol-crotonic” type of condensation of

• corresponding acetylated (hetero)arenes which are easily accessible reagents, including commercially available ones. It is well known that the reaction of isatins 7 with methyl ketones 8 leads to the formation of aldol-type adducts 9 under catalysis with mild bases, such as secondary or tertiary amines. These

• the corresponding acetylated (hetero)arenes 8a–m. Dehydration of the initially obtained aldol-type adducts into 3-(2-oxo-2-(hetero)arylethylidene)indolin-2-ones 10 has been carried out in acetic acid solution with addition of hydrochloric acid (method A), or in CH2Cl2 solution with an excess of SOCl2

Ruthenium-catalyzed C–H activation of thioxanthones

• Danny Wagner and
• Stefan Bräse

Beilstein J. Org. Chem. 2015, 11, 431–436, doi:10.3762/bjoc.11.49

• /bjoc.11.49 Abstract Thioxanthones – being readily available in one step from thiosalicylic acid and arenes – were used in ruthenium-catalyzed C–H-activation reaction to produce 1-mono- or 1,8-disubstituted thioxanthones in good to excellent yields. Scope and limitation of this reaction are presented

• chemistry aiming at a high degree of substitution seems to be well explored [17][18]. This fact motivated us to extend existing methods [14][15] for the synthesis of substituted thioxanthones. We were intrigued by the fact that carbonyl-substituted arenes can undergo a smooth C–H activation and alkylation

Cross-dehydrogenative coupling for the intermolecular C–O bond formation

• Igor B. Krylov,
• Vera A. Vil’ and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2015, 11, 92–146, doi:10.3762/bjoc.11.13

• = F (Scheme 3). The pyridine moiety served as the directing group in many works to accomplish the ortho-acyloxylation of arenes 4 giving products 5 (Table 1). The reactions were catalyzed by copper, palladium, or rhodium salts. Carboxylic acids or their salts, as well as aldehydes, methylarenes

• arenes (Scheme 4). The pyridine, pyrimidine, or pyrazole moiety serves as the directing group in the oxidative ortho-alkoxylation of arenes 16 with the Cu(OAc)2/AgOTf/O2 system giving coupling products 17 (Scheme 5) [47]. It is supposed that copper is inserted into the C–H bond of arene, the resulting Cu

• quinoline-8-amine directing moiety was used for copper-catalyzed aerobic ortho-aryloxylation and alkoxylation of arenes 59 with electron donating or electron withdrawing substituents to afford products 60 [66] (Scheme 12). The method is applicable to a wide range of OH-reagents; the molar ratio OH-reagent

Come-back of phenanthridine and phenanthridinium derivatives in the 21st century

• Lidija-Marija Tumir,
• Marijana Radić Stojković and
• Ivo Piantanida

Beilstein J. Org. Chem. 2014, 10, 2930–2954, doi:10.3762/bjoc.10.312

• phenanthridines. Microwave-mediated intramolecular Diels–Alder cyclization of o-furyl(allylamino)arenes followed by spontaneous aromatization yielded dihydrophenanthridines, which upon exposure to UV light (315−400 nm) were oxidized into (aza)phenanthridines (Scheme 9) [26]. Synthetic pathways based on the

• , here are described several innovative approaches, with potential to be developed for a large versatility of phenanthridine derivatives or application of previously not used starting materials (for instance microwave-mediated intramolecular Diels−Alder cyclization of o-furyl(allylamino)arenes). For the

Inherently chiral calix[4]arenes via oxazoline directed ortholithiation: synthesis and probe of chiral space

• Simon A. Herbert,
• Laura J. van Laeren,
• Dominic C. Castell and
• Gareth E. Arnott

Beilstein J. Org. Chem. 2014, 10, 2751–2755, doi:10.3762/bjoc.10.291

• Simon A. Herbert Laura J. van Laeren Dominic C. Castell Gareth E. Arnott Department of Chemistry and Polymer Science, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa 10.3762/bjoc.10.291 Abstract The diastereoselective oxazoline-directed lithiation of calix[4]arenes is

• reported with diastereoselective ratios of greater than 100:1 in some instances. Notably, it has been found that the opposite diastereomer can be accessed via this approach merely through the choice of an alkyllithium reagent. The inherently chiral oxazoline calix[4]arenes have also been preliminarily

• ; Introduction Calix[4]arenes form an important class of supramolecules that have been widely studied since the seminal work of Gutsche in the 1970’s [1]. The reason for this interest stems from the calix[4]arene’s three dimensional bowl-shaped structure which imparts them with a number of interesting attributes

Exploration of C–H and N–H-bond functionalization towards 1-(1,2-diarylindol-3-yl)tetrahydroisoquinolines

• Michael Ghobrial,
• Marko D. Mihovilovic and
• Michael Schnürch

Beilstein J. Org. Chem. 2014, 10, 2186–2199, doi:10.3762/bjoc.10.226

• immediately. Although a broad range of (hetero)arenes undergo C–H-arylation under copper catalysis, heterocycles possessing acidic N–H bonds react at the nitrogen preferentially [52][53]. Moreover, directing groups such as acetyl (in combination with a hypervalent iodine aryl source) [42], or 2-pyridinyl

Synthesis of trifluoromethyl-substituted pyrazolo[4,3-c]pyridines – sequential versus multicomponent reaction approach

• Barbara Palka,
• Angela Di Capua,
• Maurizio Anzini,
• Gyté Vilkauskaité,
• Algirdas Šačkus and
• Wolfgang Holzer

Beilstein J. Org. Chem. 2014, 10, 1759–1764, doi:10.3762/bjoc.10.183

• substituent by treatment with excessive POCl3, gave the chloroaldehyde 2 [19] (Scheme 1). Although Sonogashira-type cross-coupling reactions are preferably accomplished with iodo(hetero)arenes – considering the general reactivity I > Br/OTf >> Cl [20] – from related examples it was known that the chloro atom

Investigations of thiol-modified phenol derivatives for the use in thiol–ene photopolymerizations

• Sebastian Reinelt,
• Monir Tabatabai,
• Urs Karl Fischer,
• Norbert Moszner,
• Andreas Utterodt and
• Helmut Ritter

Beilstein J. Org. Chem. 2014, 10, 1733–1740, doi:10.3762/bjoc.10.180

• ]. Many efforts have been undertaken in the last decades aiming to face and overcome these limitations [1][4][5][6][7][8]. For instance the design of tailored (meth)acrylates based on calix[4]arenes [9][10] or tricyclodecane [11][12] backbones and use of ring-opening monomers as cyclopropane derivatives

Aryl substitution of pentacenes

• Andreas R. Waterloo,
• Anna-Chiara Sale,
• Dan Lehnherr,
• Frank Hampel and
• Rik R. Tykwinski

Beilstein J. Org. Chem. 2014, 10, 1692–1705, doi:10.3762/bjoc.10.178

• a similar range as found for pentacene-based PAH dyads 2a–c in which the pendant aryl groups are linked by an ethynyl spacer that allows electronic communication between the two arenes [18]. The range of oxidation potentials between TIPSPc, 2a–c, and 3a–k is, however, quite narrow, suggesting that

Clicked and long spaced galactosyl- and lactosylcalix[4]arenes: new multivalent galectin-3 ligands

• Silvia Bernardi,
• Paola Fezzardi,
• Gabriele Rispoli,
• Stefania E. Sestito,
• Francesco Peri,
• Francesco Sansone and
• Alessandro Casnati

Beilstein J. Org. Chem. 2014, 10, 1672–1680, doi:10.3762/bjoc.10.175

• . Initially, two galactosylcalix[4]arenes were prepared starting from saccharide units and calixarene cores which differ in the relative dispositions of the alkyne and azido groups. Once the most convenient synthetic pathway was selected, two further lactosylcalix[4]arenes were obtained, one in the cone, the

• galectin-1 [22]. The opposite behavior was observed for the 1,3-alternate derivative II, able to inhibit Gal-1 but not Gal-3. On the basis of these findings, we herein report the synthesis of a new subfamily of galactosyl- and lactosylcalix[4]arenes 1–4 (Figure 2) which are characterized by long

• hydrophilic spacers between the glycosyl units and the multivalent calixarene scaffold. We also report on preliminary studies of the interaction of the novel subfamily of galactosyl- and lactosylcalix[4]arenes with Gal-3 by surface plasmon resonance (SPR). Results and Discussion Synthesis of the

Silver and gold-catalyzed multicomponent reactions

• Giorgio Abbiati and
• Elisabetta Rossi

Beilstein J. Org. Chem. 2014, 10, 481–513, doi:10.3762/bjoc.10.46

• intermediacy of an organosilver compound, namely silver acetilide (Csp–Ag) [101]. The direct carboxylation of active C–H bonds of (hetero)arenes [102] and terminal alkynes [103] with CO2 in the presence of copper or gold-based catalysts has also been reported. However, these latter transformations require

A catalyst-free multicomponent domino sequence for the diastereoselective synthesis of (E)-3-[2-arylcarbonyl-3-(arylamino)allyl]chromen-4-ones

• Pitchaimani Prasanna,
• Pethaiah Gunasekaran,
• Subbu Perumal and
• J. Carlos Menéndez

Beilstein J. Org. Chem. 2014, 10, 459–465, doi:10.3762/bjoc.10.43

• . There are a few scattered literature reports on the use of DMF as a reducing agent, the first of which seems to be the reduction of diazonium tetrafluoroborate salts to arenes [58]. DMF has also been described as a reducing agent acting by hydride transfer in Pd-catalyzed processes, where the metal

Continuous flow nitration in miniaturized devices

• Amol A. Kulkarni

Beilstein J. Org. Chem. 2014, 10, 405–424, doi:10.3762/bjoc.10.38

• , the initial reaction rates are reported to be higher when the inlet velocity of the reacting mixture is increased, a fact later elaborated in detail by Dummann et al. [43]. Continuous flow nitration of a few important arenes using the standard nitrating mixture in a CYTOS microreactor was carried out

Carbenoid-mediated nucleophilic “hydrolysis” of 2-(dichloromethylidene)-1,1,3,3-tetramethylindane with DMSO participation, affording access to one-sidedly overcrowded ketone and bromoalkene descendants^§

• Rudolf Knorr,
• Thomas Menke,
• Johannes Freudenreich and
• Claudio Pires

Beilstein J. Org. Chem. 2014, 10, 307–315, doi:10.3762/bjoc.10.28

• Friedel–Crafts acylation of arenes by the acid chloride of 10. This possibility was repudiated, however, because the similar acyl chloride t-Bu2CH–CO–Cl did not acylate benzene [37][38]. Instead, the technique [39] of acylating an aryllithium compound such as 34 by a lithium carboxylate such as 36 to form

Cu-Mediated trifluoromethylation of benzyl, allyl and propargyl methanesulfonates with TMSCF₃

• Xueliang Jiang and
• Feng-Ling Qing

Beilstein J. Org. Chem. 2013, 9, 2862–2865, doi:10.3762/bjoc.9.322

• ; methanesulfonates; organo-fluorine; trifluoromethylation; Introduction Fluorinated organic molecules are extremely important in agrochemicals, pharmaceuticals and materials [1][2][3][4][5][6]. In recent years, (trifluoroethyl)arenes have drawn increasing attention in medicinal chemistry and related fields [7][8][9

• ]. Different methods have been developed for the synthesis of (trifluoroethyl)arenes, such as Cl–F exchange of the trichloroethyl derivatives [10], reduction of the (trifluoroethyl)aryl derivatives [11] and addition of 2,2-difluorostyrene derivatives [12]. Compared to these methods, the direct transition metal

• generally employed to afford various (trifluoroethyl)arenes. Although these methods are proven efficient, it is still highly desirable to develop new protocols from economic consideration. In continuation of our research on transition metal-mediated trifluoromethylation [22][23][24][25][26][27], we report

Novel supramolecular affinity materials based on (−)-isosteviol as molecular templates

• Christina Lohoelter,
• Malte Brutschy,
• Daniel Lubczyk and
• Siegfried R. Waldvogel

Beilstein J. Org. Chem. 2013, 9, 2821–2833, doi:10.3762/bjoc.9.317

• particular as templates for tracing air-borne arenes at low concentration. The affinities of the synthesized materials towards different air-borne arenes were determined by 200 MHz quartz crystal microbalances. Keywords: affinity materials; (−)-Isosteviol; supramolecular chemistry; triphenylene ketals

Flow microreactor synthesis in organo-fluorine chemistry

• Hideki Amii,
• Aiichiro Nagaki and
• Jun-ichi Yoshida

Beilstein J. Org. Chem. 2013, 9, 2793–2802, doi:10.3762/bjoc.9.314

• flow microreactor systems have been studied extensively [29][30][31][32][33][34][35][36]. The reactions of arenes with F2 gas cause not only substitution (aromatic fluorination) but also side reactions such as fluorine-addition, polymerization and so on due to the high reactivity of F2 gas [37][38][39

New developments in gold-catalyzed manipulation of inactivated alkenes

• Michel Chiarucci and
• Marco Bandini

Beilstein J. Org. Chem. 2013, 9, 2586–2614, doi:10.3762/bjoc.9.294

• and high enantioselectivity (Table 2). 4 Formation of C–C bonds Besides heteroatoms, the electrophilic activation of alkenes by gold catalysts can be exploited also to form new C–C bonds. Early achievements relied on the use of active methylene compounds or electron rich arenes as carbon nucleophiles

• is woth mentioning, that a 1:1 mixture of AuCl3 and AgOTf promoted the ring-closing processes of arenes 68, delivering the corresponding dihydrobenzopyrans, tetralins and tetrahydroquinolines 69 in good yields (Scheme 19a). Experimental controls with deuterium labelled compounds suggested the step

Recent advances in transition metal-catalyzed Csp²-monofluoro-, difluoro-, perfluoromethylation and trifluoromethylthiolation

• Grégory Landelle,
• Armen Panossian,
• Sergiy Pazenok,
• Jean-Pierre Vors and
• Frédéric R. Leroux

Beilstein J. Org. Chem. 2013, 9, 2476–2536, doi:10.3762/bjoc.9.287

• trifluoromethylated arenes in good yields, and a variety of functional groups is tolerated under the mild conditions of the process. The reaction with aryl bromides or triflates is less efficient. The success of this Pd-catalyzed trifluoromethylation is due to highly hindered phosphorus ligands like BrettPhos, which

• ) acetate as additives proved essential for achieving high yields of the desired trifluoromethylated arenes. 2-Arylpyridines, but also other aryl-substituted heteroarenes were successfully trifluoromethylated with complete regioselectivity in the position ortho to the aryl–heteroaryl bond, with moderate to

• -methylformamide as an additive appeared essential. On the other hand, the counteranion of sulfonium in Umemoto’s reagent had no influence on the reaction. Variously substituted arenes underwent trifluoromethylation with moderate to excellent yields (Table 6). Interestingly, bromo-, chloro- or ester-substituted

Crystal design using multipolar electrostatic interactions: A concept study for organic electronics

• Peer Kirsch,
• Qiong Tong and
• Harald Untenecker

Beilstein J. Org. Chem. 2013, 9, 2367–2373, doi:10.3762/bjoc.9.272

• fluorinated arenes, without expanding the geometry too much. Arene–perfluoroarene interactions are well known to stabilize molecular crystals [11][12][13] through multipolar electrostatic interactions, and there are a few examples for their use in organic electronics [10][14]. Another point to consider are

• pattern of the compound (Figure 3). The packing of 1 shows two dominant features: one is the slipped-stack motif of the arenes with an average interplanar distance of 363 pm. The slippage is not exactly half a period as intended, but slightly more. However, it clearly reflects the quadrupolar pattern of