CF₃SO₂X (X = Na, Cl) as reagents for trifluoromethylation, trifluoromethylsulfenyl-, -sulfinyl- and -sulfonylation and chlorination. Part 2: Use of CF₃SO₂Cl

• Hélène Chachignon,
• Hélène Guyon and
• Dominique Cahard

Beilstein J. Org. Chem. 2017, 13, 2800–2818, doi:10.3762/bjoc.13.273

• -free and recyclable. A variety of heteroarenes, like pyrroles, oxazoles, furanes, thiophenes, indoles and pyrazines were successfully converted into the corresponding trifluoromethylated products in moderate to good yields (Scheme 27). Remarkably, a side chlorination reaction was observed during the

CF₃SO₂X (X = Na, Cl) as reagents for trifluoromethylation, trifluoromethylsulfenyl-, -sulfinyl- and -sulfonylation. Part 1: Use of CF₃SO₂Na

• Hélène Guyon,
• Hélène Chachignon and
• Dominique Cahard

Beilstein J. Org. Chem. 2017, 13, 2764–2799, doi:10.3762/bjoc.13.272

• metals found in Langlois’ reagent could be responsible for reaction initiation. The scope was evaluated on pyridines, pyrroles, indoles, pyrimidines, pyrazines, phthalazines, quinoxalines, deazapurine, thiadiazoles, uracils, xanthenes and pyrazolino-pyrimidines (Scheme 35). The combination of previous

Conjugated nitrosoalkenes as Michael acceptors in carbon–carbon bond forming reactions: a review and perspective

• Yaroslav D. Boyko,
• Valentin S. Dorokhov,
• Alexey Yu. Sukhorukov and
• Sema L. Ioffe

Beilstein J. Org. Chem. 2017, 13, 2214–2234, doi:10.3762/bjoc.13.220

• unreactive under these conditions. Electron-rich aromatic heterocyclic compounds such as pyrroles and indoles enter reactions with nitrosoalkenes more smoothly [44][45][46][47][48][49][50][51][52][53][54][55]). The addition of nitrosoalkenes to pyrroles and indoles is a convenient and mild strategy for the

• -pot double addition of pyrroles (and indoles) to nitrosoalkenes derived from α,α’-dihalooximes 70 [60][61][62] (Scheme 25). The synthesis of bis-pyrroles 71 is carried out in water as the solvent. As pointed by the authors, heterogenous conditions can accelerate the rate of reaction compared to

• NSA14 to electron-rich arenes. Addition of nitrosoalkenes NSA14 to pyrroles and indoles. Reaction of phosphinyl nitrosoalkenes NSA15 with indole. Reaction of pyrrole with α,α’-dihalooximes 70. Synthesis of indole-derived psammaplin A analogue 72. Synthesis of tryptophanes by reduction of

Regiodivergent condensation of 5-alkoxycarbonyl-1H-pyrrol-2,3-diones with cyclic ketazinones en route to spirocyclic scaffolds

• Alexey Yu. Dubovtsev,
• Maksim V. Dmitriev,
• Аndrey N. Maslivets and
• Michael Rubin

Beilstein J. Org. Chem. 2017, 13, 2179–2185, doi:10.3762/bjoc.13.218

• spirocondensation of 5-alkoxycarbonyl-1H-pyrrole-2,3-diones (serving as 1,2-bis-electrophiles) with cyclic ketazinones (serving as either 1,3-C,N- or 1,3-C,O-bis-nucleophiles). Results and Discussion Previously, we demonstrated a convenient approach towards spiro[indole-3,2’-pyrroles] 3 based on catalyst-free

• in tautomeric form 18 (Scheme 5). Surprisingly, an alternative direction of spirocyclization involving the reaction of tautomeric form 19 and affording lactam rings proceeded exclusively. The corresponding spiro[indole-3,2’-pyrroles] 21 were obtained exclusively in good yields (Scheme 5). The

High-speed vibration-milling-promoted synthesis of symmetrical frameworks containing two or three pyrrole units

• Marco Leonardi,
• Mercedes Villacampa and
• J. Carlos Menéndez

Beilstein J. Org. Chem. 2017, 13, 1957–1962, doi:10.3762/bjoc.13.190

• achieved by a different approach involving the homodimerization of 1-allyl- or 1-homoallylpyrroles by application of cross-metathesis chemistry. Keywords: diversity-oriented synthesis; mechanochemistry; multicomponent reactions; pyrroles; solvent-free synthesis; Introduction Symmetrical molecules formed

Mechanochemical synthesis of small organic molecules

• Tapas Kumar Achar,
• Anima Bose and
• Prasenjit Mal

Beilstein J. Org. Chem. 2017, 13, 1907–1931, doi:10.3762/bjoc.13.186

• Hantzsch pyrrole synthesis is well known for the construction of poly substituted pyrroles [121][122]. In 1998, Jung and co-workers reported polymer supported solid phase synthesis of N-substituted pyrroles [123]. In 2013, Menendez and co-workers reported a ceric ammonium nitrate (CAN) and silver-nitrate

• intermediate β-enaminone which further reacted with α-iodoketone following by a cyclo-condensation which resulted in the substituted pyrroles shown in Scheme 31. The Biginelli reaction is a well-known 3-component reaction for the synthesis of dihydropyrimidinones [124][125]. During the last few decades many

• also observed that an oven-dried catalyst worked effectively to give 99% of product with 99% ee up to few cycles. Heterocycle synthesis Multicomponent reactions [135], cyclo-condensations and cascaded transformations are common strategies to make heterocyclic ring [113] systems like pyrroles, pyrans

Nucleophilic and electrophilic cyclization of N-alkyne-substituted pyrrole derivatives: Synthesis of pyrrolopyrazinone, pyrrolotriazinone, and pyrrolooxazinone moieties

• Işıl Yenice,
• Sinan Basceken and
• Metin Balci

Beilstein J. Org. Chem. 2017, 13, 825–834, doi:10.3762/bjoc.13.83

• N-alkyne-substituted pyrrole derivatives 7a–d. A practical method is the coupling reaction of substituted pyrroles with alkynyl bromides using catalytic CuSO4·5H2O and 1,10-phenanthroline [31]. When alkynylation with 11a was carried out at 85 °C, the conversion was only 12%. We assume this is due to

Effect of the ortho-hydroxy group of salicylaldehyde in the A³ coupling reaction: A metal-catalyst-free synthesis of propargylamine

• Sujit Ghosh,
• Kinkar Biswas,
• Suchandra Bhattacharya,
• Pranab Ghosh and
• Basudeb Basu

Beilstein J. Org. Chem. 2017, 13, 552–557, doi:10.3762/bjoc.13.53

• (MAO) type B inhibitors [6] often used for the treatment of neuropsychiatric disorders such as Alzheimer’s and Parkinson diseases. These alkynylamines are also important building blocks for the synthesis of N-bearing compounds such as β-lactams [7][8], pyrroles [9], pyrrolidines [10], pyrrolophanes [11

Iodination of carbohydrate-derived 1,2-oxazines to enantiopure 5-iodo-3,6-dihydro-2H-1,2-oxazines and subsequent palladium-catalyzed cross-coupling reactions

• Michal Medvecký,
• Igor Linder,
• Luise Schefzig,
• Hans-Ulrich Reissig and
• Reinhold Zimmer

Beilstein J. Org. Chem. 2016, 12, 2898–2905, doi:10.3762/bjoc.12.289

• modifications and synthetic applications of 1,2-oxazines 3 including the preparation of seven-membered N,O-heterocycles by ring enlargement [5], functionalization of the enol ether unit [6][7][8][9][10][11], and N,O-cleavage reactions leading to amino alcohols [8][10][12], pyrroles [13] or α,β-unsaturated β

Synthesis of pyrrolo[2,1-f][1,2,4]triazin-4(3H)-ones: Rearrangement of pyrrolo[1,2-d][1,3,4]oxadiazines and regioselective intramolecular cyclization of 1,2-biscarbamoyl-substituted 1H-pyrroles

• Kkonnip Son and
• Seong Jun Park

Beilstein J. Org. Chem. 2016, 12, 1780–1787, doi:10.3762/bjoc.12.168

• Pyrrolo[2,1-f][1,2,4]triazin-4(3H)-ones 12 have been easily prepared via nucleophile-induced rearrangement of pyrrolooxadiazines 11 and regioselective intramolecular cyclization of 1,2-biscarbamoyl-substituted 1H-pyrroles 10. In this work, we demonstrated that the described synthetic approaches can be

Multicomponent reactions: A simple and efficient route to heterocyclic phosphonates

• Mohammad Haji

Beilstein J. Org. Chem. 2016, 12, 1269–1301, doi:10.3762/bjoc.12.121

• 4:1 in the presence of 4 Å molecular sieves (Scheme 59) [97]. A sequential three-component enamine–azoene annulation reaction of primary aliphatic amines 292, activated methylene compounds 293, and 1,2-diaza-1,3-dienes (DDs, 294) has been reported to give polysubstituted pyrroles 295 (Scheme 60) [98

• ]. The desired phosphono-substituted pyrroles were isolated in 41–87% yield under solvent and catalyst-free conditions. Kaboudin et al. described a three-component, catalyst-free decarboxylative coupling of proline (296) with aldehydes 297 and dialkyl phosphonates to afford pyrrolidinylphosphonates 300

• . Multicomponent reaction of alkanedials, acetamide and acetyl chloride in the presence of PCl3 and acetic acid. An oxidative domino three-component synthesis of polyfunctionalized pyridines. A sequential one-pot three-component synthesis of polysubstituted pyrroles. Three-component decarboxylative coupling of

Conjugate addition–enantioselective protonation reactions

• James P. Phelan and
• Jonathan A. Ellman

Beilstein J. Org. Chem. 2016, 12, 1203–1228, doi:10.3762/bjoc.12.116

• formed from Zn(NTf2)2 and Ph-dbfox ligand (S)-85, pyrroles 83 were added to imides 84 to produce 85 in high yield and modest to excellent enantioselectivity. Exploring a number of achiral imides, the authors found that an isoxazolidinone auxiliary enhanced the reactivity and minimized enolate A1,3

• -interactions to provide the best yield and enantioselectivity. N-Alkylpyrroles were effective substrates, adding with high enantioselectivity (94:6 to 99:1 er). The enantioselectivity of the transformation was significantly lower only for pyrroles that lacked substitution on nitrogen and for N-phenylpyrroles

• enantioselective Friedel–Crafts addition of pyrroles to imides 84. Kobayashi’s enantioselective addition of malonates to α-substituted N-acryloyloxazolidinones. Chen and Wu’s enantioselective addition of thiophenol to N-methacryloyl benzamide. Tan’s enantioselective addition of secondary phosphine oxides and

Catalytic asymmetric synthesis of biologically important 3-hydroxyoxindoles: an update

• Bin Yu,
• Hui Xing,
• De-Quan Yu and
• Hong-Min Liu

Beilstein J. Org. Chem. 2016, 12, 1000–1039, doi:10.3762/bjoc.12.98

• group described the first chiral imidodiphosphoric acid-catalyzed enantioselective Friedel–Crafts reactions of indoles and pyrroles with 3-hydroxy-3-indolyloxindoles, giving the 3,3-diaryloxindoles in excellent yields (99% yield) and with excellent enantioselectivities (98% ee) at low catalyst loading

A convenient route to symmetrically and unsymmetrically substituted 3,5-diaryl-2,4,6-trimethylpyridines via Suzuki–Miyaura cross-coupling reaction

• Dariusz Błachut,
• Joanna Szawkało and
• Zbigniew Czarnocki

Beilstein J. Org. Chem. 2016, 12, 835–845, doi:10.3762/bjoc.12.82

• teams in the construction of polyarylated benzenes [56], pyridines [57][58][59][60], thiophenes [61][62], quinoxalines [63], pyrazoles [64] pyrroles [65], pyrimidines [66][67], benzofuranes [68], imidazo[1,2-a]pyridines [69], diaryl/heteroaryl methanes [70], and indoles [71], bearing differently

• construction of unsymmetrically arylated pyrroles, thiophenes and 2,6- and 3,5-diarylpyridines. In order to test the utility of the above mentioned approach, a series of trial cross couplings were performed on a microscale according to route 3 with a variety of electron-poor and electron-rich boronic acids

Creating molecular macrocycles for anion recognition

• Amar H. Flood

Beilstein J. Org. Chem. 2016, 12, 611–627, doi:10.3762/bjoc.12.60

• produce shorter, stronger contacts. Calix[4]pyrroles are a case in point [18]. This conformational rearrangement cannot occur within the triazolophane and so, while the fluoride may have shorter hydrogen bonds, it has fewer contacts than chloride. For iodide, it is simply too big for a single

Hydroquinone–pyrrole dyads with varied linkers

• Hao Huang,
• Christoffer Karlsson,
• Maria Strømme,
• Martin Sjödin and
• Adolf Gogoll

Beilstein J. Org. Chem. 2016, 12, 89–96, doi:10.3762/bjoc.12.10

• , Box 576, SE-751 23 Uppsala, Sweden 10.3762/bjoc.12.10 Abstract A series of pyrroles functionalized in the 3-position with p-dimethoxybenzene via various linkers (CH2, CH2CH2, CH=CH, C≡C) has been synthesized. Their electronic properties have been deduced from 1H NMR, 13C NMR, and UV–vis spectra to

• organic electrical energy storage [6]. Structure of pyrrole/hydroquinone derivatives 3-(2,5-dimethoxyphenyl)-1H-pyrrole (1) and 3-(1,4-dihydroxyphenyl)-1H-pyrrole (2) [5]. Hydroquinone dimethyl ether functionalized pyrroles with linkers L discussed in this study. 1H NMR spectra (400 MHz, CDCl3 solution

Star-shaped tetrathiafulvalene oligomers towards the construction of conducting supramolecular assembly

• Masahiko Iyoda and
• Masashi Hasegawa

Beilstein J. Org. Chem. 2015, 11, 1596–1613, doi:10.3762/bjoc.11.175

• –32°, indicating the conformational flexibility of the pyrrole–benzene linkage. The calculated torsion angles between the pyrroles and central benzenes of 38, 40, and 42 are 34, 45, and 59°, respectively, and the non-planar structures of 38, 40, and 42 are in good agreement with the high-field shift

• of α-protons of pyrroles in the 1H NMR spectra: δ 6.89 (38), 6.41 (40), 5.93 ppm (42). Star-shaped TTF 10-mer 44 was also synthesized by SNAr reaction of the sodium salt of 36 with decafluorobiphenyl (44%) [75] (Figure 13). In the CV measurements (Figure 14), tetrasubstituted 40 shows typical two

Deproto-metallation of N-arylated pyrroles and indoles using a mixed lithium–zinc base and regioselectivity-computed CH acidity relationship

• Mohamed Yacine Ameur Messaoud,
• Ghenia Bentabed-Ababsa,
• Madani Hedidi,
• Aïcha Derdour,
• Floris Chevallier,
• Yury S. Halauko,
• Oleg A. Ivashkevich,
• Vadim E. Matulis,
• Laurent Picot,
• Valérie Thiéry,
• Thierry Roisnel,
• Vincent Dorcet and
• Florence Mongin

Beilstein J. Org. Chem. 2015, 11, 1475–1485, doi:10.3762/bjoc.11.160

• , Centre de Diffractométrie X, Institut des Sciences Chimiques de Rennes, UMR 6226, CNRS-Université de Rennes 1, Bâtiment 10B, Campus de Beaulieu, 35042 Rennes, France 10.3762/bjoc.11.160 Abstract The synthesis of N-arylated pyrroles and indoles is documented, as well as their functionalization by

• deprotonative metallation using the base in situ prepared from LiTMP and ZnCl2·TMEDA (1/3 equiv). With N-phenylpyrrole and -indole, the reactions were carried out in hexane containing TMEDA which regioselectively afforded the 2-iodo derivatives after subsequent iodolysis. With pyrroles and indoles bearing N

• using the DFT B3LYP method in order to rationalize the experimental results. Keywords: CH acidity; indoles; iodolysis; mixed lithium–zinc bases; pyrroles; Introduction Pyrrole occurs in very important natural products such as tetrapyrrolic (linear) bilirubinoids, and (cyclic) porphyrins and corrins

Cathodic hydrodimerization of nitroolefins

• Michael Weßling and
• Hans J. Schäfer

Beilstein J. Org. Chem. 2015, 11, 1163–1174, doi:10.3762/bjoc.11.131

• caused by the NH groups of the pyrroles. Their hydrogen bonds could influence the relative energies of the transition states leading to the diastereomers. One of the two meso-configurations can be assigned to isomer 22a because of the missing coupling between the benzylic methine protons. The 1H NMR data

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

• systems [11][27], to the incorporation of MPTTFs and BPTTFs into more complex molecular architectures such as macrocycles [8][9][14], calix-pyrroles [1][10][11], calixarenes [29] and porphyrins [30]. Note that for MPTTFs, R1 and R2 can be either the same or different. Here, we present recent developments

2-(1-Hydroxypropyn-2-yl)-1-vinylpyrroles: the first successful Favorsky ethynylation of pyrrolecarbaldehydes

• A. V. Ivanov,
• V. S. Shcherbakova,
• I. A. Ushakov,
• L. N. Sobenina,
• O. V. Petrova,
• A. I. Mikhaleva and
• B. A. Trofimov

Beilstein J. Org. Chem. 2015, 11, 228–232, doi:10.3762/bjoc.11.25

• modified conditions of the Favorsky reaction has been implemented to pave an expedient route to important biomolecules containing a pyrrole ring. Keywords: acetylene; ethynylation; Favorsky reaction; 1-vinylpyrrole-2-carbaldehyde; Introduction Functionalized pyrroles bearing a terminal acetylenic moiety

• and hydroxy function as substituents, particularly 2-(1-hydroxypropyn-2-yl)pyrroles, represent important biomolecular intermediates and attractive synthetic building blocks for drug precursors. Currently, they find a growing application in the synthesis of protein kinase inhibitors or modulators [1

• ] and novel cyclin-dependent kinase inhibitors [2]. Such functionalized pyrroles are intermediates for endothelial differentiation gene (EDG-1) receptor antagonists. The latter are effective in preventing and/or treating inflammations, diseases associated with abnormal angiogenesis, cerebral vascular

Enhancing the reactivity of 1,2-diphospholes in cycloaddition reactions

• Almaz Zagidullin,
• Vasili Miluykov,
• Elena Oshchepkova,
• Artem Tufatullin,
• Olga Kataeva and
• Oleg Sinyashin

Beilstein J. Org. Chem. 2015, 11, 169–173, doi:10.3762/bjoc.11.17

• significant interest for the preparation of highly effective catalysts, materials for light-emitting diodes and nonlinear optics [3][4]. In contrast to furans, thiophenes and pyrroles, phospholes display cycloaddition and complexation reactions and can be used as starting materials for caged phosphines

Efficient deprotection of F-BODIPY derivatives: removal of BF₂ using Brønsted acids

• Mingfeng Yu,
• Joseph K.-H. Wong,
• Cyril Tang,
• Peter Turner,
• Matthew H. Todd and
• Peter J. Rutledge

Beilstein J. Org. Chem. 2015, 11, 37–41, doi:10.3762/bjoc.11.6

• diversifying the F-BODIPY framework [9]. F-BODIPYs are readily prepared by condensing aldehydes, acyl chlorides or anhydrides with pyrroles and trapping the resulting dipyrrin in situ with boron trifluoride [9][10][11]. F-BODIPYs are generally stable and chemically robust, with photophysical properties that

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

• –2 mol % palladium catalysts, the target 2,5-diheteroarylated thiophenes were obtained in moderate to good yields and with a wide variety of heteroarenes such as thiazoles, thiophenes, furans, pyrroles, pyrazoles or isoxazoles. Moreover, sequential heteroarylation reactions allow the access to 2,5

• promotes the 2,5-diheteroarylation of 2,5-dibromothiophene in the presence of a variety of heteroarenes such as thiophenes, furans, pyrroles, pyrazoles or isoxazoles as the coupling partners. The sequential diheteroarylation of 2,5-dibromothiophene was also found to be possible to afford 2,5

Lewis acid-catalyzed redox-neutral amination of 2-(3-pyrroline-1-yl)benzaldehydes via intramolecular [1,5]-hydride shift/isomerization reaction

• Chun-Huan Jiang,
• Xiantao Lei,
• Le Zhen,
• Hong-Jin Du,
• Xiaoan Wen,
• Qing-Long Xu and
• Hongbin Sun

Beilstein J. Org. Chem. 2014, 10, 2892–2896, doi:10.3762/bjoc.10.306

• mL) at room temperature or reflux and monitored by TLC. After completion of the reaction (about 24 h), the solvent was removed by evaporation and the residue was purified by flash column chromatography on silica gel to give N-arylpyrrole 3. Synthesis of N-substituted pyrroles via redox-neutral