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

• monofluoromethylation was described by J. Hu. Aryl iodides were submitted to a Cu-catalyzed (CuTC = copper thiophene-2-carboxylate) debenzoylative fluoroalkylation with 2-PySO2CHFCOR followed by desulfonylation (Scheme 2) [49]. It has been shown that the (2-pyridyl)sulfonyl moiety is important for the Cu-catalysis. 2

• reagents, we will focus on the study by Q. Shen et al. – although, once again, both are closely related. In the latter, catalytic copper(II) thiophene carboxylate was used in the second stage in the presence of 1,10-phenanthroline as a ligand; Togni’s reagent served as the CF3-source (Table 34). The

• reaction, including natural product related or complex small molecules (Figure 18) [37]. 3.3.3 Ni-catalyzed perfluoroalkylation of Csp2–H bonds. Two early reports by Y.-Z. Huang et al. described Ni-catalyzed perfluoroalkylation of anilines, benzene, furan, thiophene and pyrrole using ω-chloroperfluoroalkyl

An overview of the synthetic routes to the best selling drugs containing 6-membered heterocycles

• Marcus Baumann and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2013, 9, 2265–2319, doi:10.3762/bjoc.9.265

• alkyl chain to moderate their bioavailability resulting in the ultimate discovery of tiagabine (2.36) which has an embedded (R)-nipecotate unit as the class indicative pharmacophore. The synthesis of tiagabine (2.36) is readily accomplished by the union of ethyl nipecotate with the bis-thiophene

Asymmetric allylic alkylation of Morita–Baylis–Hillman carbonates with α-fluoro-β-keto esters

• Lin Yan,
• Zhiqiang Han,
• Bo Zhu,
• Caiyun Yang,
• Choon-Hong Tan and
• Zhiyong Jiang

Beilstein J. Org. Chem. 2013, 9, 1853–1857, doi:10.3762/bjoc.9.216

• with hetereoaromatic groups, such as thiophene and furan (Table 2, 2n–o). Conclusion We have developed an asymmetric allylic alkylation of MBH carbonates with α-fluoro-β-ketoesters, catalyzed by a commercially available Cinchona alkaloid. Several fluorinated adducts, with chiral quaternary carbon

A practical synthesis of long-chain iso-fatty acids (iso-C₁₂–C₁₉) and related natural products

• Mark B. Richardson and
• Spencer J. Williams

Beilstein J. Org. Chem. 2013, 9, 1807–1812, doi:10.3762/bjoc.9.210

• ][45][46], organomagnesium (sp2–sp3) [47], or organocopper (sp3–sp3) [48][49] cross-couplings; or (2) bidirectional extension of a central thiophene C4-fragment [50]. Two fundamentally different approaches worth special mention are the synthesis of the iso-C14 acid 3 by direct hydro-isopropylation of

Controlled synthesis of poly(3-hexylthiophene) in continuous flow

• Helga Seyler,
• Jegadesan Subbiah,
• David J. Jones,
• Andrew B. Holmes and
• Wallace W. H. Wong

Beilstein J. Org. Chem. 2013, 9, 1492–1500, doi:10.3762/bjoc.9.170

• because of readily available reagents, relatively mild reaction conditions, and short polymerization time. In the most basic reaction setup, 2,5-dibromo-3-hexylthiophene is treated with one equivalent of alkylmagnesium chloride to form a mixture of monosubstituted thiophene Grignard monomers (Scheme 1a

• thiophene Grignard monomer 2 is prepared from the magnesium exchange reaction of an alkyl Grignard reagent and 2,5-dibromo-3-hexylthiophene (1, Scheme 1a). It should be noted here that a mixture of Grignard monomers 2a and 2b is produced in this step, typically in a ratio of 75:25. Only 2a participates in

• reaction conditions for P3HT synthesis to continuous-flow processing. The polymerization step in flow was examined first with the thiophene Grignard monomer prepared in batch. Good solubility and solvent compatibility in the polymerization are essential factors to be evaluated for the translation into flow

Incorporation of perfluorohexyl-functionalised thiophenes into oligofluorene-truxenes: synthesis and physical properties

• Neil Thomson,
• Alexander L. Kanibolotsky,
• Joseph Cameron,
• Tell Tuttle,
• Neil J. Findlay and
• Peter J. Skabara

Beilstein J. Org. Chem. 2013, 9, 1243–1251, doi:10.3762/bjoc.9.141

• with longer oligofluorene arms the effects of the perfluorohexylthiophene unit on larger oligomers was explored. The effect of steric hindrance from the perfluorohexyl chain was also evaluated by altering the position of the chain on the thiophene moiety. Keywords: oligomers; perfluorinated-materials

• by using the RI-J approximation [23]. The hexyl chains on the fluorene units were shortened to methyl groups in the model in order to decrease the computational cost of the simulation. The main structural difference observed is the degree of twisting between the fluorene and thiophene in the two

• ) are essentially degenerate and show a splitting due to a slight break in symmetry. This is also the case for the LUMO and LUMO+1 of each isomer (ΔE[T1-3FTh] = 0.013 eV and ΔE[T1-4FTh] = 0.0047 eV). The HOMO−1 and HOMO of the compounds show there to be a larger contribution of the thiophene unit to the

Enhancement of efficiency in organic photovoltaic devices containing self-complementary hydrogen-bonding domains

• Rohan J. Kumar,
• Jegadesan Subbiah and
• Andrew B. Holmes

Beilstein J. Org. Chem. 2013, 9, 1102–1110, doi:10.3762/bjoc.9.122

• ] followed by a Knoevenagel condensation provided the target compound 2 in excellent yield. The solubilizing strategy of incorporating alkyl groups on the thiophene unit provided the compound with excellent solubility in a wide range of common solvents. Optoelectronic properties In chloroform solution the UV

• dipolar absorption transitions observed (Figure 2b). A conformational search followed by DFT optimization of the resultant structures showed that the monomer has an energetic preference for the flat structure shown in Figure 2b, with a barrier to rotation for the thiophene alkene bond of 272 KJ mol−1

• . This is supported by the crystal structure of a related NH-cyanopyridone structure determined by Würthner et al. [29], which exhibited a similarly oriented, flat thiophene cyanopyridone structure in a hydrogen-bonded dimer. The barrier for rotation, as determined by temperature-dependent 1H NMR

Synthesis, photophysical and electrochemical characterization of terpyridine-functionalized dendritic oligothiophenes and their Ru(II) complexes

• Amaresh Mishra,
• Elena Mena-Osteritz and
• Peter Bäuerle

Beilstein J. Org. Chem. 2013, 9, 866–876, doi:10.3762/bjoc.9.100

• ; oligothiophene; spectroscopy; terpyridine; Introduction Research concerning the design, characterization and application of organic semiconductors is carried out intensively due to the attractive prospects of their application in organic and molecular electronics [1][2][3][4][5]. In particular, thiophene-based

• the tpy-ethynyl type have proven to be very useful and provide a library of photoresponsive complexes derived from the basic Ru(II)-tpy type module [23][24][25][26][27]. Recently, tpy-complexes that incorporate π-conjugated thiophene or thienylene-ethynylene units became available, and the study of

• -transfer processes. A series of shape-persistent all-thiophene dendrons and dendrimers were recently introduced by Advincula et al. [39][40] and us [41][42]. These dendritic oligothiophenes are excellent model compounds for the study of fundamental photophysical and electronic properties. Furthermore, core

Ring-opening reaction of 2,5-dioctyldithieno[2,3-b:3',2'-d]thiophene in the presence of aryllithium reagents

• Hao Zhong,
• Jianwu Shi,
• Jianxun Kang,
• Shaomin Wang,
• Xinming Liu and
• Hua Wang

Beilstein J. Org. Chem. 2013, 9, 767–774, doi:10.3762/bjoc.9.87

• ring-opening reaction of 2,5-dioctyldithieno[2,3-b:3',2'-d]thiophene with aryllithium in THF at low temperature to generate 2'-arylthio-3,3'-bithiophene-2-carbaldehydes is studied. Nine examples are explored and all the products are characterized by 1H NMR, 13C NMR and HRMS. The relative relationship

• between the structures of aryl groups and the efficiency of ring-opening reactions are discussed. Keywords: aryllithium reagents; 2'-arylthio-3,3'-bithiophene-2-carbaldehyde; dithieno[2,3-b:3',2'-d]thiophene; nucleophilicity; ring-opening reaction; Introduction Due to the promising optical and

• electrical properties, the derivatives of dithieno[2,3-b:3',2'-d]thiophene (DTT), as one type of fused oligothiophene, have shown their potential applications in organic electronics [1][2][3][4]. The work on the synthesis of DTT derivatives and the chemical stability of the DTT core is of particular interest

The chemistry of bisallenes

• Henning Hopf and
• Georgios Markopoulos

Beilstein J. Org. Chem. 2012, 8, 1936–1998, doi:10.3762/bjoc.8.225

Extending the utility of [Pd(NHC)(cinnamyl)Cl] precatalysts: Direct arylation of heterocycles

• Anthony R. Martin,
• Anthony Chartoire,
• Alexandra M. Z. Slawin and
• Steven P. Nolan

Beilstein J. Org. Chem. 2012, 8, 1637–1643, doi:10.3762/bjoc.8.187

• sterically demanding 3-methylbenzothiophene (9) (Table 4, entries 8–10). Closely related reactivity was observed for 6 and 9, as these were arylated in comparable yields (Table 4, entry 1 vs 8, 3 vs 9 and 6 vs 10). A more challenging heterocycle, 2-methylthiophene (11), was investigated. Simple thiophene

• efficiently than the electron poor 4-fluorobromobenzene. An opposite effect of the electronics was observed by Doucet et al. in their ligandless procedure at low catalyst loadings [43][44]. This is surely due to the nature of the catalyst and thus offers complementary direct arylation methods for thiophene

• arylation of various benzothiophenes, thiophene and imidazopyridine. C–H functionalization of such heterocycles was performed in moderate to good yields by using only 0.1–0.01 mol % of precatalyst. This study highlights the fact that [Pd(NHC)(cin)Cl] complexes are multipurpose precatalysts as they may be

Synthesis and characterization of low-molecular-weight π-conjugated polymers covered by persilylated β-cyclodextrin

• Aurica Farcas,
• Ana-Maria Resmerita,
• Andreea Stefanache,
• Mihaela Balan and
• Valeria Harabagiu

Beilstein J. Org. Chem. 2012, 8, 1505–1514, doi:10.3762/bjoc.8.170

• wide emission band during operation [8]. Taking into account the relevant photophysical properties of these organic compounds, new synthetic approaches were developed. Copolymerization of fluorene with thiophene, bithiophene or other aromatic comonomers is an alternative method for tuning the optical

Cation affinity numbers of Lewis bases

• Christoph Lindner,
• Raman Tandon,
• Boris Maryasin,
• Evgeny Larionov and
• Hendrik Zipse

Beilstein J. Org. Chem. 2012, 8, 1406–1442, doi:10.3762/bjoc.8.163

• ). All MCA values refer to reaction at the phosphorus atom, if not mentioned otherwise. Surveying the MCA values obtained for phosphanes with furane (218, 219, 222, 224, 227, 228), thiophene (223, 225, 226, 231, 233, 237), cyclopentadiene (232, 234–236, 238, 241, 242, 244, 245), thiazole (217, 221, 230

The effect of the formyl group position upon asymmetric isomeric diarylethenes bearing a naphthalene moiety

• Renjie Wang,
• Shouzhi Pu,
• Gang Liu and
• Shiqiang Cui

Beilstein J. Org. Chem. 2012, 8, 1018–1026, doi:10.3762/bjoc.8.114

• fluorophores via a Schiff base structure. In a previous work, we developed a new class of diarylethenes with a naphthalene group and a thiophene group. The results revealed that these molecules have excellent photochromism with good fatigue resistance and thermal stability [37]. In this study, in order to

Synthesis and characterization of Sant-75 derivatives as Hedgehog-pathway inhibitors

• Chao Che,
• Song Li,
• Bo Yang,
• Shengchang Xin,
• Zhixiong Yu,
• Taofeng Shao,
• Chuanye Tao,
• Shuo Lin and
• Zhen Yang

Beilstein J. Org. Chem. 2012, 8, 841–849, doi:10.3762/bjoc.8.94

• (PPh3)4, PhMe, Na2CO3, H2O, 85 °C; (b) N-Boc-cyclohexane-1,4-diamine, THF, NaBH(OAc)3; (c) DMF, NaH, PrI, 0 °C to rt.; (d) 3-chlorobenzo[b]thiophene-2-carbonyl chloride, CH2Cl2, Et3N; (e) CH2Cl2, TFA. Substituent-modifications on the motif A. Reagents and conditions: (a) CH2Cl2, Et3N; (b) CH2Cl2, TFA

Thiophene-based donor–acceptor co-oligomers by copper-catalyzed 1,3-dipolar cycloaddition

• Stefanie Potratz,
• Amaresh Mishra and
• Peter Bäuerle

Beilstein J. Org. Chem. 2012, 8, 683–692, doi:10.3762/bjoc.8.76

• –donor type, in which thiophene moieties work as donor and 1,2,3-triazoles as acceptor units. In this respect, terminally ethynylated (oligo)thiophenes were coupled to halogenated (oligo)thiophenes in the presence of sodium azide and a copper catalyst. Optoelectronic properties of various thiophene-1,2,3

• -triazole co-oligomers were investigated by UV–vis spectroscopy and cyclic voltammetry. Several co-oligomers were electropolymerized to the corresponding conjugated polymers. Keywords: acetylene; azide; click chemistry; thiophene; triazole; Introduction Oligo- and polythiophenes are among the most

• temperatures gave an incomplete conversion of 2-iodothiophene (3), whereas at 95 °C the 2-azidothiophene eventually decomposed. Therefore, we found that a temperature of 50 °C was a good compromise between the reactivity of the halogenated thiophene in the nucleophilic substitution to 2-azidothiophene, and the

Syntheses and applications of furanyl-functionalised 2,2’:6’,2’’-terpyridines

• Jérôme Husson and
• Michael Knorr

Beilstein J. Org. Chem. 2012, 8, 379–389, doi:10.3762/bjoc.8.41

• ], as catalysts [8], etc. On the other hand, five-membered heterocycles such as furan, pyrrole, selenophene, tellurophene or thiophene possess interesting features such as the capability to undergo chemical and electrochemical oxidation to afford polymers. These polymeric materials generally exhibit

• . Miscellaneous utilization of furanyl-functionalised tpys Terpyridines functionalised with five-membered heterocycles, especially thiophene [13], and their derived complexes have proved to be interesting materials in the field of dye-sensitized solar cells (DSSC) [55]. Understanding in depth both the

Reduction of benzylic alcohols and α-hydroxycarbonyl compounds by hydriodic acid in a biphasic reaction medium

• Michael Dobmeier,
• Josef M. Herrmann,
• Dieter Lenoir and
• Burkhard König

Beilstein J. Org. Chem. 2012, 8, 330–336, doi:10.3762/bjoc.8.36

• position (Table 1, entries 4 and 6) and aromatic hydroxy groups (Table 2, entry 7) or aromatic ethers (Table 1, entry 5) were not affected. Moreover, heterocycles such as thiophene (Table 1, entry 7) were stable under these conditions whereas furans (Table 1, entry 8) were decomposed due to ring opening

Synthesis, solid-state fluorescence properties, and computational analysis of novel 2-aminobenzo[4,5]thieno[3,2-d]pyrimidine 5,5-dioxides

• Kenichirou Yokota,
• Masayori Hagimori,
• Naoko Mizuyama,
• Yasuhisa Nishimura,
• Hiroshi Fujito,
• Yasuhiro Shigemitsu and
• Yoshinori Tominaga

Beilstein J. Org. Chem. 2012, 8, 266–274, doi:10.3762/bjoc.8.28

• -autoclave. Compound 3b was also synthesized by the reaction of 2a with 2-(diaminomethylene)benzo[b]thiophene-3(2H)-one 1,1-dioxide (4), which was easily obtained from 1a by using 28% ammonia in methanol under reflux. The reactions of 1a, 2a, and amines 5a–c (benzylamine, piperidine, and aniline) in pyridine

• ]pyrimidine 5,5-dioxides (3a–g), were synthesized in good yields by a convenient one-pot reaction of 2-[bis(methylsulfanyl)methylene]benzo[b]thiophene-3(2H)-one 1,1-dioxide (1a) with guanidine carbonate (2a) or (S)-methylisothiourea sulfate (2b) under reflux in pyridine. Benzo[4,5]thieno[3,2-d]pyrimidine

• Alq3 as the standard sample. The fluorescence of the standard sample and all subject compounds was measured at 272 nm excitation. Synthesis 2-Amino-4-(methylsulfanyl)benzo[4,5]thieno[3,2-d]pyrimidine 5,5-dioxide (3a): A mixture of 2-[bis(methylsulfanyl)methylene]benzo[b]thiophene-3(2H)-one 1,1-dioxide

Synthesis of multivalent host and guest molecules for the construction of multithreaded diamide pseudorotaxanes

• Nora L. Löw,
• Egor V. Dzyuba,
• Boris Brusilowskij,
• Lena Kaufmann,
• Elisa Franzmann,
• Wolfgang Maison,
• Emily Brandt,
• Daniel Aicher,
• Arno Wiehe and
• Christoph A. Schalley

Beilstein J. Org. Chem. 2012, 8, 234–245, doi:10.3762/bjoc.8.24

• rise to divalent axle 22, which was isolated as a side product in 37% yield. This molecule may be useful for other divalent hosts, such as two macrocycles connected through a butadiyne spacer or a thiophene unit. Such hosts have been reported previously [103] and are not included here. Formation of

Improved syntheses of high hole mobility phthalocyanines: A case of steric assistance in the cyclo-oligomerisation of phthalonitriles

• Daniel J. Tate,
• Rémi Anémian,
• Richard J. Bushby,
• Suwat Nanan,
• Stuart L. Warriner and
• and Benjamin J. Whitaker

Beilstein J. Org. Chem. 2012, 8, 120–128, doi:10.3762/bjoc.8.14

• bis-alkylation of thiophene (1), oxidation to the corresponding sulfone 3, and treatment with fumaronitrile (Scheme 1, top line). However, for most of the phthalonitriles we have made, we have found that a much better route is the nickel-catalysed reaction of an alkylzinc iodide with the bistriflate

• velocity as a function of electric field (185 °C). (c) Temperature-dependence of the hole mobility within the Colh phase. The error bars represent 2σ. (Top) original synthesis of compound 7a from thiophene (Oc = n-octyl) [19]. (Below) shortened synthesis of α-alkylated derivatives through the triflate of

Imidazole as a parent π-conjugated backbone in charge-transfer chromophores

• Jiří Kulhánek and
• Filip Bureš

Beilstein J. Org. Chem. 2012, 8, 25–49, doi:10.3762/bjoc.8.4

• , such as thiophene or thiazole; (ii) the improvement of the electron-withdrawing ability of the used acceptor; and (iii) the elongation of the π-conjugated pathway. Thus, the first series of chromophores (5a–c) was completed with the thiophene-derived system 6 [14] with a tricyanovinyl acceptor moiety

• and chromophores 7a–c [33] featuring a thiophene π-linker and a nitrostyryl acceptor. The molecular structures of compounds 6 and 5c were also confirmed by X-ray analysis [34]. The last series of investigated compounds involved donor 4,5-disubstituted imidazoles 8a–d [35] with acceptors at C2 linked

• derivatives 14 bearing a cyanoacrylic moiety connected to imidazole C2 by thiophene or thiazole π-linkers were recently utilized as dye-sensitized solar cells with an efficiency up to 6.3% [41]. Several similar classes of imidazole-derived push–pull compounds can be found in the literature. They were mainly

Sexithiophenes as efficient luminescence quenchers of quantum dots

• Christopher R. Mason,
• Yang Li,
• Paul O’Brien,
• Neil J. Findlay and
• Peter J. Skabara

Beilstein J. Org. Chem. 2011, 7, 1722–1731, doi:10.3762/bjoc.7.202

• stirred for 20 minutes after which time thiophene-2-carboxaldehyde (3.1 mL, 32.9 mmol) was added and the mixture stirred for a further 10 min. Another portion of lithium diisopropylamide mono(tetrahydrofuran) (1.5 M in cyclohexanes, 21.9 mL, 32.9 mmol) was added and the mixture was stirred for 15 min

• after which time thiophene-2-carboxaldehyde (3.1 mL, 32.9 mmol) was added and the mixture was stirred for a further 5 min. The reaction mixture was stirred for a further 1.5 h whilst being allowed to warm to room temperature. Saturated sodium hydrogencarbonate (150 mL) was added and the organic phase

• the starting materials and impurities, then ethyl acetate to remove the product) to afford A as a red oil (~10.1 g; product unstable, no data). [5-(Thiophene-2-carbonyl)-2-thioxo-[1,3]dithiol-4-yl]thiophen-2-yl-methanone (B) [29] To a solution of the diol A (10.1 g), in dichloromethane (250 mL

Recent advances in direct C–H arylation: Methodology, selectivity and mechanism in oxazole series

• Cécile Verrier,
• Pierrik Lassalas,
• Laure Théveau,
• Guy Quéguiner,
• François Trécourt,
• Francis Marsais and
• Christophe Hoarau

Beilstein J. Org. Chem. 2011, 7, 1584–1601, doi:10.3762/bjoc.7.187

• )-catalyzed direct arylation of (benz)oxazoles with aryl halides; (a) Itami's procedure [80]; (b) Miura's procedure [81]. Dehydrogenative cross-coupling of (benz)oxazoles; (a) Pd(II)- and Cu(II)-catalyzed cross-coupling of benzoxazole with thiophene [82]; (b) Pd(II)- and Cu(II)-catalyzed cross-coupling of

Pseudo five-component synthesis of 2,5-di(hetero)arylthiophenes via a one-pot Sonogashira–Glaser cyclization sequence

• Dominik Urselmann,
• Dragutin Antovic and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2011, 7, 1499–1503, doi:10.3762/bjoc.7.174

• title compounds. This novel pseudo five-component synthesis starting from iodo(hetero)arenes is particularly suitable as a direct access to well-defined thiophene oligomers, which are of peculiar interest in materials science. Keywords: C–C coupling; copper; multicomponent reactions; palladium

• -iodo-nitrobenzene (1g) a concomitant reduction of the nitro groups to the amines was observed, giving rise to the dianilino thiophene 2g. Most interestingly, even the linear five-ring-containing derivatives “PPTPP” (2n) and “T5” (2o), which are important charge-transport molecules in materials science

• cleavage of the protection group and the formation of several byproducts were observed leading to a significantly lower isolated yield of the corresponding thiophene 2p. Conclusion In summary we have developed an economical and efficient one-pot sequence for transforming (hetero)aryl iodides into