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

• prepare BPTTFs using homocoupling reactions and functionalised MPTTFs using cross-coupling reactions with a variety of 1,3-dithiole-2-thiones (19). Subsequently, the incorporation of more complex functionality is discussed. We show how the 2-cyanoethyl protecting group can be used to afford MPTTFs

• published scale [25]. The equivalent reaction can be conducted using 7 to give BPTTF 5b with a similar yield of 79% [36], a modest improvement on the reported yield of 73% for the Boc-protected analogue [35]. The synthesis of MPTTFs can be achieved using cross-coupling reactions between 6 and 1,3-dithiole-2

• species [27]) can also be used in cross-coupling reactions, exemplified by its reaction with 19g to give 4g (Scheme 3 and Table 1) [36]. Our group has previously shown that it is also possible to introduce substituents directly onto the pyrrole ring of MPTTF 4d [40]. Further functionalisation of MPTTFs

An intramolecular C–N cross-coupling of β-enaminones: a simple and efficient way to precursors of some alkaloids of Galipea officinalis

• Hana Doušová,
• Radim Horák,
• Zdeňka Růžičková and
• Petr Šimůnek

Beilstein J. Org. Chem. 2015, 11, 884–892, doi:10.3762/bjoc.11.99

• interesting for preparations on a larger scale. With the conditions chosen for the bromo derivatives, we turned our attention to the chloro derivatives. As chloro derivatives are more challenging substrates for cross-coupling reactions, we started with the successful catalytic system (Table 1, entry 3) but

Design, synthesis and photochemical properties of the first examples of iminosugar clusters based on fluorescent cores

• Mathieu L. Lepage,
• Antoine Mirloup,
• Manon Ripoll,
• Fabien Stauffert,
• Anne Bodlenner,
• Raymond Ziessel and
• Philippe Compain

Beilstein J. Org. Chem. 2015, 11, 659–667, doi:10.3762/bjoc.11.74

• function to yield the trimethylsilylacetylene derivatives 9 and 11 using standard Sonogashira–Hagihira cross-coupling reactions promoted by low valent palladium precursors [62]. Excellent yields were obtained for the trisubstituted derivatives (88 to 95%). Two diagnostic NMR signals of the poly(ethylene

TTFs nonsymmetrically fused with alkylthiophenic moieties

• Rafaela A. L. Silva,
• Bruno J. C. Vieira,
• Marta M. Andrade,
• Isabel C. Santos,
• Sandra Rabaça,
• Dulce Belo and
• Manuel Almeida

Beilstein J. Org. Chem. 2015, 11, 628–637, doi:10.3762/bjoc.11.71

• converted to transition metal complexes based on extended thiophene/TTF-fused dithiolene ligands. They were obtained by cross-coupling reactions between alkylated thio and oxo compounds. The incorporation of these alkyl groups in the thiophenic ring is expected to increase the solubility of these TTFs and

Weakly nucleophilic potassium aryltrifluoroborates in palladium-catalyzed Suzuki–Miyaura reactions: relative reactivity of K[4-RC₆F₄BF₃] and the role of silver-assistance in acceleration of transmetallation

• Vadim V. Bardin,
• Anton Yu. Shabalin and
• Nicolay Yu. Adonin

Beilstein J. Org. Chem. 2015, 11, 608–616, doi:10.3762/bjoc.11.68

• consumption of K[4-RC6F4BF3] and SEP of the respective 4-RC6F4 group does not show certain correlation. Conclusion 1. The relative reactivities of K[4-RC6F4BF3] in the Ag(I)-assisted Pd-catalyzed cross-coupling reactions with 3-IC6H4F, 4-IC6H4F, 4-IC6H4CH3 or 4-BrC6H4CH3 in the presence of P(t-Bu)3 or PPh3

Diastereoselective and enantioselective conjugate addition reactions utilizing α,β-unsaturated amides and lactams

• Katherine M. Byrd

Beilstein J. Org. Chem. 2015, 11, 530–562, doi:10.3762/bjoc.11.60

• of boron to α,β-unsaturated carbonyl compounds. Enantioenriched organoboron reagents are useful because they can be used in cross-coupling reactions [98][100] or they can be converted into the corresponding alcohol [101] while retaining the stereochemical information. Transition metals such as Cu

Bis(vinylenedithio)tetrathiafulvalene analogues of BEDT-TTF

• Erdal Ertas,
• İlknur Demirtas and
• Turan Ozturk

Beilstein J. Org. Chem. 2015, 11, 403–415, doi:10.3762/bjoc.11.46

• coupling reactions. While the cross couplings of 26a–d with 28 and 31 [53] led to the formation of 29a–d and 32a–d, respectively, along with the self coupling products 4, 30 and 3, coupling of 27a–c with 28 gave 33a–c and the self coupling products 34a–c and 30. The cross coupled product 35 from 27c and 31

• of the side products 16–19 can be taken as evidence for the proposed reaction mechanism. The thione sulfur atoms of 11a–d and 13a–c were converted into their corresponding oxo forms 26a–d and 27a–c, respectively, using mercury acetate (Scheme 4) [46][53][54]. These were then subjected to cross

An unusually stable chlorophosphite: What makes BIFOP–Cl so robust against hydrolysis?

• Roberto Blanco Trillo,
• Jörg M. Neudörfl and
• Bernd Goldfuss

Beilstein J. Org. Chem. 2015, 11, 313–322, doi:10.3762/bjoc.11.36

• ]. There are also some applications of phosphine halides used as ligands in catalytic reactions, for example, in cross-coupling reactions and hydroformylations [10][11][12]. We recently reported the application of the fenchole-based, phosphine halide BIFOP–Hal (Hal = F, Cl, Br) (Scheme 1) in an

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

• -dehydrogenative coupling can be employed to form a new bond with high atomic efficiency and does not require additional synthetic steps for the introduction of functional groups (for example, such as -Hal, -OTf, -BR2, -SnR3, -SiR3, -ZnHal, -MgHal) into molecules necessary in other cross-coupling reactions

An improved procedure for the preparation of Ru(bpz)₃(PF₆)₂ via a high-yielding synthesis of 2,2’-bipyrazine

• Danielle M. Schultz,
• James W. Sawicki and
• Tehshik P. Yoon

Beilstein J. Org. Chem. 2015, 11, 61–65, doi:10.3762/bjoc.11.9

• reaction, we turned our attention towards the use of more reactive aryl iodides. A screen of solvents commonly used in Pd-catalyzed cross-coupling reactions revealed that DMF provided the highest yields (Table 1, entries 3–5). We next examined the effect of varying equivalents of the terminal reductant

Sequential decarboxylative azide–alkyne cycloaddition and dehydrogenative coupling reactions: one-pot synthesis of polycyclic fused triazoles

• Kuppusamy Bharathimohan,
• Thanasekaran Ponpandian,
• A. Jafar Ahamed and
• Nattamai Bhuvanesh

Beilstein J. Org. Chem. 2014, 10, 3031–3037, doi:10.3762/bjoc.10.321

• describe a one-pot protocol for the synthesis of a novel series of polycyclic triazole derivatives. Transition metal-catalyzed decarboxylative CuAAC and dehydrogenative cross coupling reactions are combined in a single flask and achieved good yields of the respective triazoles (up to 97% yield). This

Palladium-catalyzed 2,5-diheteroarylation of 2,5-dibromothiophene derivatives

• Fatma Belkessam,
• Aidene Mohand,
• Jean-François Soulé,
• Abdelhamid Elias and
• Henri Doucet

Beilstein J. Org. Chem. 2014, 10, 2912–2919, doi:10.3762/bjoc.10.309

• semiconductors [2]. Due to these multiple uses, the discovery of a simpler access to terthiophene derivatives would be very useful. Suzuki, Stille or Negishi Pd-catalyzed cross-coupling reactions represent some of the most efficient methods for the preparation of 2,5-diheteroarylated thiophenes [3][4][5][6][7][8

• than other Pd-catalyzed cross-coupling reactions as it avoids the preparation of an organometallic derivative and also as the major byproducts of the reaction are not metallic salts but a base associated to HX. The metal-catalyzed direct arylation of a wide variety of heteroarenes using aryl halides as

A novel 4-aminoantipyrine-Pd(II) complex catalyzes Suzuki–Miyaura cross-coupling reactions of aryl halides

• Claudia A. Contreras-Celedón,
• Darío Mendoza-Rayo,
• José A. Rincón-Medina and
• Luis Chacón-García

Beilstein J. Org. Chem. 2014, 10, 2821–2826, doi:10.3762/bjoc.10.299

• are tolerated. Keywords: 4-aminoantipyrine; arylboronic acids; biaryls; cross-coupling; palladium(II) complex; Introduction The sp2–sp2 carbon–carbon bond formation through cross-coupling reactions catalyzed by metal complexes has emerged as a powerful tool in organic synthesis [1][2][3][4][5][6

• ppm, with its integration indicating one proton. This result suggests to us that the palladium interacts with the carbonyl and amine groups of the pyrazole ring of 4-AAP. The synthesized 4-AAP–Pd(II) complex was used to carry out all palladium-catalyzed Suzuki–Miyaura cross-coupling reactions

• biphenyl compounds with moderate yields (Scheme 2 compounds 3e–3h, 3m–3p, 3u–3x). In addition to the yield, the turnover number (TON in Scheme 2) of the 4-AAP–Pd(II) catalyst was measured, and found to be moderate (400–700) for all 24 tested cross-coupling reactions, suggesting that the catalyst is also

A simple copper-catalyzed two-step one-pot synthesis of indolo[1,2-a]quinazoline

• Chunpu Li,
• Lei Zhang,
• Shuangjie Shu and
• Hong Liu

Beilstein J. Org. Chem. 2014, 10, 2441–2447, doi:10.3762/bjoc.10.254

• convenient methods to prepare nitrogen-containing tetracyclic compounds incorporating the bioactive indole motif in organic chemistry and medicinal chemistry. Over the past decades, copper catalysts have been proven highly powerful for various cross-coupling reactions, including Ullmann-type couplings of

Phosphinocyclodextrins as confining units for catalytic metal centres. Applications to carbon–carbon bond forming reactions

• Matthieu Jouffroy,
• Rafael Gramage-Doria,
• David Sémeril,
• Dominique Armspach,
• Dominique Matt,
• Werner Oberhauser and
• Loïc Toupet

Beilstein J. Org. Chem. 2014, 10, 2388–2405, doi:10.3762/bjoc.10.249

• , Buchwald and Hartwig on the use of monophosphine ligands in cross-coupling reactions, notably carbon–carbon ones such as the Mizoroki–Heck [1][2][3] and Suzuki–Miyaura reactions [4][5][6], there is a renewed interest for tertiary phosphines that favour the formation of singly phosphorus-ligated complexes

• + Na]+. General procedure for palladium-catalysed Heck cross-coupling reactions: In an oven-dried Schlenk tube, a solution of [Pd(OAc)2] in DMF, a solution of HUGPHOS-1/2 or WIDEPHOS ligands in DMF, aryl bromide (1 equiv), styrene (2 equiv), Cs2CO3 (2 equiv), decane (internal reference) and additional

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

Synthesis of rigid p-terphenyl-linked carbohydrate mimetics

• Maja Kandziora and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2014, 10, 1749–1758, doi:10.3762/bjoc.10.182

• conjugates may have even higher binding affinities and specificities than their flexible multivalent equivalents [14][15]. The rigidity of the system is supposed to improve the overall activity of the ligands by overcoming the entropic penalty of flexible multivalent scaffolds [16]. Cross-coupling reactions

• prepared p-bromophenyl-substituted bicyclic 1,2-oxazine derivatives 12, 13, 15 and 16 provide options to perform cross-coupling reactions such as Buchwald/Hartwig, Heck, Hiyama, Kumada, Sonogashira or Stille couplings. In order to examine the conditions for Suzuki cross-couplings we subjected bicyclic

Synthesis of new, highly luminescent bis(2,2’-bithiophen-5-yl) substituted 1,3,4-oxadiazole, 1,3,4-thiadiazole and 1,2,4-triazole

• Anastasia S. Kostyuchenko,
• Vyacheslav L.Yurpalov,
• Aleksandra Kurowska,
• Wojciech Domagala,
• Adam Pron and
• Alexander S. Fisyuk

Beilstein J. Org. Chem. 2014, 10, 1596–1602, doi:10.3762/bjoc.10.165

• and Discussion Synthetic toolbox There are several approaches to the synthesis of 2,5-bis(2,2 '-bithiophen-5-yl)-1,3,4-oxadiazoles and 1,3,4-thiadiazoles. Transition metal-catalysed cross-coupling reactions, such as Stille, Suzuki etc. are typically used for the formation of thiophene–thiophene or

Synthesis of chiral N-phosphoryl aziridines through enantioselective aziridination of alkenes with phosphoryl azide via Co(II)-based metalloradical catalysis

• Jingran Tao,
• Li-Mei Jin and
• X. Peter Zhang

Beilstein J. Org. Chem. 2014, 10, 1282–1289, doi:10.3762/bjoc.10.129

• may be further functionalized via other transformations such as palladium-catalyzed cross-coupling reactions. Conclusion In summary, we have shown that the Co(II) complex of the new D2-symmetric chiral porphyrin 3,5-DiMes-QingPhyrin, [Co(P6)], is an effective metalloradical catalyst for asymmetric

Hindered aryl bromides for regioselective palladium-catalysed direct arylation at less favourable C5-carbon of 3-substituted thiophenes

• Rongwei Jin,
• Charles Beromeo Bheeter and
• Henri Doucet

Beilstein J. Org. Chem. 2014, 10, 1239–1245, doi:10.3762/bjoc.10.123

• variety of arylated thiophenes. For such coupling reactions, the major byproduct is a base associated to HX, instead of metallic salts which are produced under the more classical Negishi, Suzuki or Stille cross-coupling reactions. Moreover, direct arylation avoids the preliminary preparation of

Palladium-catalysed cross-coupling reaction of ultra-stabilised 2-aryl-1,3-dihydro-1H-benzo[d]1,3,2-diazaborole compounds with aryl bromides: A direct protocol for the preparation of unsymmetrical biaryls

• Siphamandla Sithebe and
• Ross S. Robinson

Beilstein J. Org. Chem. 2014, 10, 1107–1113, doi:10.3762/bjoc.10.109

• acids, arylboronate esters and potassium aryltrifluoroborate salts because they are versatile coupling partners in metal-catalysed cross-coupling reactions. On the other hand, their nitrogen analogues, namely, 1,3,2-benzodiazaborole-type compounds have been studied extensively for their intriguing

• cross-coupling; Introduction Arylboronic acids 1, arylboronate esters 2 and potassium aryltrifluoroborate salts 3 (Figure 1) have received considerable attention and have found a special place as mild and versatile nucleophilic coupling partners for carbon–carbon bond-forming cross-coupling reactions

Preparation of phosphines through C–P bond formation

• Iris Wauters,
• Wouter Debrouwer and
• Christian V. Stevens

Beilstein J. Org. Chem. 2014, 10, 1064–1096, doi:10.3762/bjoc.10.106

• obtained was 45%. The same group has shown that imidazolium based ionic liquids can be used as a medium to perform the C–P cross-coupling reactions. This method allows an easy separation of the product from the catalyst and the recycling of the palladium catalyst [176]. Stelzer and co-workers have

Clean and fast cross-coupling of aryl halides in one-pot

• Valerica Pandarus,
• Geneviève Gingras,
• François Béland,
• Rosaria Ciriminna and
• Mario Pagliaro

Beilstein J. Org. Chem. 2014, 10, 897–901, doi:10.3762/bjoc.10.87

• ]. Of direct relevance to this research report, Giroux and co-workers reported the homogeneously palladium-catalyzed one-pot borylation/Suzuki coupling reactions already in 1997 [7]. Yet, it remains desirable to efficiently heterogenize palladium catalytic species used in cross-coupling reactions with

Rapid pseudo five-component synthesis of intensively blue luminescent 2,5-di(hetero)arylfurans via a Sonogashira–Glaser cyclization sequence

• Fabian Klukas,
• Alexander Grunwald,
• Franziska Menschel and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2014, 10, 672–679, doi:10.3762/bjoc.10.60

• . 2,5-dihalogenated furans can be in principle employed in cross-coupling reactions, however, the poor stability of these dihalogenated precursors renders this approach very tedious [29]. Recent publications report gold-catalyzed syntheses of di(hetero)arylfurans starting from arylbutadiynes [30][31

Isocyanide-based multicomponent reactions towards cyclic constrained peptidomimetics

• Gijs Koopmanschap,
• Eelco Ruijter and
• Romano V.A. Orru

Beilstein J. Org. Chem. 2014, 10, 544–598, doi:10.3762/bjoc.10.50

• -substituted thiazoles (38–78%), probably via a thiazolone intermediate. It is noteworthy that the triflate-thiazoles can be further elongated via cross coupling reactions, resulting in even higher functionalized 5-substituted or non-functionalized thiazoles in good to excellent yields (51–95%, Scheme 41) [108