Meta-metallation of N,N-dimethylaniline: Contrasting direct sodium-mediated zincation with indirect sodiation-dialkylzinc co-complexation

• David R. Armstrong,
• Liam Balloch,
• Eva Hevia,
• Alan R. Kennedy,
• Robert E. Mulvey,
• Charles T. O'Hara and
• Stuart D. Robertson

Beilstein J. Org. Chem. 2011, 7, 1234–1248, doi:10.3762/bjoc.7.144

• usually inert towards orthodox organozinc reagents including benzene [15] and naphthalene [16]. These studies – that have been structurally supported by X-ray crystallography in tandem with NMR spectroscopy – have uncovered the chemical synergy that these mixed-metal alternatives can exhibit, which

One-pot four-component synthesis of pyrimidyl and pyrazolyl substituted azulenes by glyoxylation–decarbonylative alkynylation–cyclocondensation sequences

• Charlotte F. Gers,
• Julia Rosellen,
• Eugen Merkul and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2011, 7, 1173–1181, doi:10.3762/bjoc.7.136

• planar, cyclic conjugation of 10 π-electrons. The dipole moment of 1a at μ = 1.08 D [20] is astoundingly large in comparison to that of naphthalene at μ = 0 D and can be rationalized by a significant contribution of cyclopentadienyl anion/tropylium cation resonance structures (Scheme 1) [19]. Since the

When gold can do what iodine cannot do: A critical comparison

• Sara Hummel and
• Stefan F. Kirsch

Beilstein J. Org. Chem. 2011, 7, 847–859, doi:10.3762/bjoc.7.97

• , where NIS was used as the electrophilic agent [90]. Alkyne activation yields the iodonaphthalene as the sole product by an analogous 6-endo process. Both methods, regardless of whether the cyclization is triggered by Au+ or I+, require an alkyl substituent at the C2-position for naphthalene formation to

Synthetic applications of gold-catalyzed ring expansions

• David Garayalde and
• Cristina Nevado

Beilstein J. Org. Chem. 2011, 7, 767–780, doi:10.3762/bjoc.7.87

• . After the first examples on the perchlorination of naphthalene with AuCl3 or AuCl by Schwemberger and Gordon in 1935 [10], almost forty years passed without a single report on the catalytic ability of gold salts, due to its presumed lack of reactivity. In 1972, Paul G. Gassman reported several studies

When cyclopropenes meet gold catalysts

• Frédéric Miege,
• Christophe Meyer and
• Janine Cossy

Beilstein J. Org. Chem. 2011, 7, 717–734, doi:10.3762/bjoc.7.82

• to the isomeric substituted naphthalene 21 as the sole product. Shi et al. had previously demonstrated that indene 20 and naphthalene 21 could be selectively formed using Cu(OTf)2 and BF3·OEt2 as catalysts, respectively, thereby highlighting the complementarities of the different electrophilic

• activators [31]. Since AgOTf and BF3·OEt2 led to the same naphthalene product 21, the authors suspected that traces of the Brønsted acid (HOTf) present in the silver salt may be the actual catalyst and may also modify the regioselectivity observed in the gold-catalyzed reaction. Thus, several basic additives

• with traces of water) should favour the formation of the more stable cyclopropyl cation 23. Afterwards, ring-opening and intramolecular Friedel–Crafts reactions should enable the formation of indene 20 or naphthalene 21. With the gold catalyst, the formation of indene 19 indicated that electrophilic

Gold-catalyzed naphthalene functionalization

• Pedro J. Pérez,
• M. Mar Díaz-Requejo and
• Iván Rivilla

Beilstein J. Org. Chem. 2011, 7, 653–657, doi:10.3762/bjoc.7.77

• bond. In addition, no byproducts derived from carbene coupling were observed. Keywords: carbene insertion; copper catalysts; diazoacetates; gold catalysts; naphthalene functionalization; selective insertion; Introduction At the end of the nineteenth century, Buchner discovered [1] the thermal and

• observed with other metal-based catalysts [4][5][6]. The above transformation with rhodium-based catalysts [7][8] has also been investigated with naphthalene as a substrate. In this case, Teyssié and co-workers showed that it could be converted, using t-butyl diazoacetate, into norcaradiene type

• derivatives, formed by the cyclopropanation of one of the double bonds of the naphthalene ring. Later, Müller and co-workers [9] showed the effect of a series of Rh2(L-L)4 in the same transformation but with ethyl diazoacetate as the carbene source. A mixture of the products (2a–d) arising from

Synthesis of 5-(2-methoxy-1-naphthyl)- and 5-[2-(methoxymethyl)-1-naphthyl]-11H-benzo[b]fluorene as 2,2'-disubstituted 1,1'-binaphthyls via benzannulated enyne–allenes

• Yu-Hsuan Wang,
• Joshua F. Bailey,
• Jeffrey L. Petersen and
• Kung K. Wang

Beilstein J. Org. Chem. 2011, 7, 496–502, doi:10.3762/bjoc.7.58

• spectrometer, the signals of the methylene hydrogens on the five-membered ring could be discerned as an AB system at δ 4.27 (J = 21 Hz) and 4.25 (J = 21 Hz). The rotational barrier of BINOL as a member of the 2,2'-disubstituted 1,1'-binaphthyls was determined to be 37.2 kcal/mol at 195 °C in naphthalene

• -butoxide (1.0 M) in 2-methyl-2-propanol, lithium diisopropylamide (LDA, 2.0 M) in heptane/THF/ethylbenzene, Pd(PPh3)2Cl2, Pd(PPh3)4, copper(I) iodide, triethylamine, 1.0 M BH3·THF solution in THF, 1-ethynylnaphthalene (18a), 2-methoxy-1-naphthaldehyde, 1-bromo-2-(methoxymethyl)naphthalene, (trimethylsilyl

Anion–π interactions influence pK_a values

• Christopher J. Cadman and
• Anna K. Croft

Beilstein J. Org. Chem. 2011, 7, 320–328, doi:10.3762/bjoc.7.42

• model systems 1–5, based on 1,8-disubstituted naphthalene (Figure 1). Such model systems have already been utilised to great effect by Cozzi and co-workers to probe π–π interactions [25][26]. Related models have also proven effective in exploring neighbouring group interactions in reactive systems, such

• corroborated in the solid state by the X-ray crystal structure of compound 4, which shows the structure as having the substituted aromatic ring roughly perpendicular to the naphthalene rings. These factors render the structures 1–5 suitable for the current study. Compounds 1–5 were titrated with TBAH to

• and is accompanied by a ring critical point from the 6-membered ring made from the additional atoms of the naphthalene moiety. The ρ value is, as can be surmised from the lower interaction energy, lower for the bond critical point between H and C for 2(a) (0.0193 e·bohr−3) than for that between H and

Supramolecular FRET photocyclodimerization of anthracenecarboxylate with naphthalene-capped γ-cyclodextrin

• Qian Wang,
• Cheng Yang,
• Gaku Fukuhara,
• Tadashi Mori,
• Yu Liu and
• Yoshihisa Inoue

Beilstein J. Org. Chem. 2011, 7, 290–297, doi:10.3762/bjoc.7.38

• .7.38 Abstract γ-Cyclodextrin (CD) derivatives with a naphthalene moiety anchored to one or two of the glucose units of the CD were synthesized in order to investigate the effects of flexible and rigid capping upon complexation, as well as Förster resonance energy transfer (FRET) and photochirogenic

• behavior of anthracenecarboxylate (AC) moieties. UV–vis, circular dichroism and fluorescence spectral studies revealed that two AC molecules are simultaneously included in the modified γ-CD cavity to form a right-handed screw and also that the naphthalene cap efficiently transfers the singlet energy to AC

• Förster resonance energy transfer (FRET) sensitization. Results and Discussion Naphthalene-capped γ-CD 6 was synthesized by the reaction of 6A,6C-ditosyl-γ-CD [23] with disodium 2,6-naphthalenedicarboxylate in DMSO. An attempt to synthesize the regioisomeric 6A,6D-(2,6-naphthalenedicarboxyl)-γ-CD by

Highly substituted benzannulated cyclooctanol derivatives by samarium diiodide-induced cyclizations

• Jakub Saadi,
• Irene Brüdgam and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2010, 6, 1229–1245, doi:10.3762/bjoc.6.141

• , Ar), 51.7, 176.3 (q, s, CO2Me) ppm. IR (neat): = 3510 (br, O-H), 3100–2850 (=C-H, C-H), 1720 (C=O) cm−1. C16H22O3 (262.3): calcd: C 73.25, H 8.45; found: C 73.43, H 8.30. Methyl (2SR,4RS,4aSR)-4-hydroxy-4-methyl-8-[(1E)-propen-1-yl]-1,2,3,4,4a,7-hexahydro-naphthalene-2-carboxylate (20): 1H NMR

Self-assembly and semiconductivity of an oligothiophene supergelator

• Pampa Pratihar,
• Suhrit Ghosh,
• Vladimir Stepanenko,
• Sameer Patwardhan,
• Ferdinand C. Grozema,
• Laurens D. A. Siebbeles and
• Frank Würthner

Beilstein J. Org. Chem. 2010, 6, 1070–1078, doi:10.3762/bjoc.6.122

• these elongated fibres form interpenetrating network in which the solvent molecules are trapped [3][4]. Organogels based on various π-systems such as oligophenylenevinylenes [5] and thienylenevinylenes [6] oligophenyleneethylenes [7], phthalocyanines [8], porphyrins [9], naphthalene and perylene

β-Hydroxy carbocation intermediates in solvolyses of di- and tetra-hydronaphthalene substrates

• Jaya S. Kudavalli and
• Rory A. More O'Ferrall

Beilstein J. Org. Chem. 2010, 6, 1035–1042, doi:10.3762/bjoc.6.118

• cis and trans isomers, kcis/ktrans = 1800 in aqueous acetonitrile. This mirrors the behaviour of the acid-catalysed dehydration of cis- and trans-naphthalene-1,2-dihydrodiols to form 2-naphthol, for which kcis/ktrans = 440, but contrasts with that for solvolysis of tetrahydronaphthalene substrates, 1

• benzene, naphthalene (1,2), phenanthrene (9,10) and 3,4-dihydronaphthalene in Figure 1 [3]. The purpose of the present work was to determine whether the same differentials apply to solvolysis reactions of dihydrodiol derivatives for which one of the hydroxy groups has been converted to a more reactive

• leaving group. In the case of benzene dihydrodiol it is hard to functionalise the hydroxy group without triggering aromatisation to phenol, at least in the case of the cis-diol. The same is true of the cis-1,2-dihydrodiol of naphthalene. However, prior methylation of the 2-hydroxy group of this substrate

Pyridinium based amphiphilic hydrogelators as potential antibacterial agents

• Sayanti Brahmachari,
• Sisir Debnath,
• Sounak Dutta and
• Prasanta Kumar Das

Beilstein J. Org. Chem. 2010, 6, 859–868, doi:10.3762/bjoc.6.101

• have synergistically led to a surge in the development of tailor-made LMWHs. The presence of an aromatic ring (for example, phenyl, naphthalene, N-fluorenyl-9-methoxycarbonyl (Fmoc), indole, pyridine) in small molecule gelator is known to have crucial influence in inducing self-aggregation towards

Aromatic and heterocyclic perfluoroalkyl sulfides. Methods of preparation

• Vladimir N. Boiko

Beilstein J. Org. Chem. 2010, 6, 880–921, doi:10.3762/bjoc.6.88

• anilines but also for N-monosubstituted substrates and even those with a free NH2 group (Scheme 11). In naphthalene and benzophenone derivatives only those rings containing hydroxy or amino groups undergo perfluoroalkylsulfanylation [74][75]. Other electron-donating substituents on the aromatic ring are

Synthesis of 2a,8b-Dihydrocyclobuta[a]naphthalene-3,4-diones

• Kerstin Schmidt and
• Paul Margaretha

Beilstein J. Org. Chem. 2010, 6, No. 76, doi:10.3762/bjoc.6.76

• Kerstin Schmidt Paul Margaretha Chemistry Department, University of Hamburg, Martin-Luther-King Platz 6, D-20146 Hamburg, Germany 10.3762/bjoc.6.76 Abstract On irradiation (λ = 350 nm) in neat hex-1-yne, naphthalene-1,2-dione monoacetals 1 afford mixtures of pentacyclic photodimers and up to 25

• products [2]. Very recently we reported the use of 1,2-dihydro-1,1-dimethoxynaphthalen-2-ones 1 as protected precursors for the synthesis of both photocyclodimers and ketene-photocycloadducts of 1,2-naphtoquinones [3][4]. Here we report the preparation of – novel – 2a,8b-dihydrocyclobuta[a]naphthalene-3,4

• room temperature. The org. phase was washed with sat. aq NaCl, dried (MgSO4) and the residue (100% conversion to product from 1H NMR) purified by CC (SiO2, pentane/Et2O 1:1) to afford the diketones 3. 1-Butyl-2a,8b-dihydrocyclobuta[a]naphthalene-3,4-dione (3a): 37 mg (85%), viscous yellow oil, Rf

Anthracene functionalized terpyridines – synthesis and properties

• Falk Wehmeier and
• Jochen Mattay

Beilstein J. Org. Chem. 2010, 6, No. 54, doi:10.3762/bjoc.6.54

• λ > 320 nm during irradiation (see Figure 1 and Figure 2) is indicative of the formation of a naphthalene derivative; in case of a symmetrical 9,10:9′,10′-cycloaddition we would expect absorption patterns at lower wavelengths, since isolated benzene derivates would be produced [16][17][18][19

Molecular recognition of organic ammonium ions in solution using synthetic receptors

• Andreas Späth and
• Burkhard König

Beilstein J. Org. Chem. 2010, 6, No. 32, doi:10.3762/bjoc.6.32

Synthesis of bis(3-{[2-(allyloxy)ethoxy]methyl}-2,4,6-trimethylbenzoyl)(phenyl)phosphine oxide – a tailor-made photoinitiator for dental adhesives

• Norbert Moszner,
• Iris Lamparth,
• Jörg Angermann,
• Urs Karl Fischer,
• Frank Zeuner,
• Thorsten Bock,
• Robert Liska and
• Volker Rheinberger

Beilstein J. Org. Chem. 2010, 6, No. 26, doi:10.3762/bjoc.6.26

• bisacylphosphine oxide WBAPO was prepared by the reaction of 2 with P,P-dichlorophenylphosphine (Scheme 4). Thus, P,P-dichlorophenylphosphine dissolved in THF was first lithiated with metallic lithium in a dry argon atmosphere in the presence of a small amount of naphthalene. The resulting dark green

• anhydrous tetrahydrofuran (THF, 10 mL) was added to a stirred mixture of lithium (1.53 g, 221 mmol), naphthalene (0.064 g, 0.50 mmol) and anhydrous THF (40 mL) in a flame dried flask under an argon atmosphere at room temperature. After 22 h, the dark green solution was transferred into another flame dried

Synthesis of indolo[3,2-b]carbazole-based new colorimetric receptor for anions: A unique color change for fluoride ions

• Ajit Kumar Mahapatra,
• Giridhari Hazra and
• Prithidipa Sahoo

Beilstein J. Org. Chem. 2010, 6, No. 12, doi:10.3762/bjoc.6.12

• ][24][25][26][27][28], there is a paucity of reports on selective naked-eye chemosensors for fluoride [29][30][31]. Nitrophenyl, nitronaphthalene urea [32][33][34], naphthalene triphenyl-phosphonium [35], benzimidazolyl pyridine [36][37] and oxidized bis(indolyl)methane [38] as signal units for

Mitomycins syntheses: a recent update

• Jean-Christophe Andrez

Beilstein J. Org. Chem. 2009, 5, No. 33, doi:10.3762/bjoc.5.33

Reversible intramolecular photocycloaddition of a bis(9-anthrylbutadienyl)paracyclophane – an inverse photochromic system. (Photoactive cyclophanes 5)

• Henning Hopf,
• Christian Beck,
• Jean-Pierre Desvergne,
• Henri Bouas-Laurent,
• Peter G. Jones and
• Ludger Ernst

Beilstein J. Org. Chem. 2009, 5, No. 20, doi:10.3762/bjoc.5.20

• observed to occur under geometrical constraints [11][12][24] through a triplet state process [25]. [4+2]-Cycloadditions can take place in a hot ground state [26]. This result is reminiscent of the [4+2]-photocycloaddition between two naphthalene substrates for the anti-[2.2](1,4)-naphthalenophane leading

Quinoline based receptor in fluorometric discrimination of carboxylic acids

• Kumaresh Ghosh,
• Suman Adhikari,
• Asoke P. Chattopadhyay and
• Purnendu Roy Chowdhury

Beilstein J. Org. Chem. 2008, 4, No. 52, doi:10.3762/bjoc.4.52

• Kumaresh Ghosh Suman Adhikari Asoke P. Chattopadhyay Purnendu Roy Chowdhury Department of Chemistry, University of Kalyani, Kalyani, Nadia-741235, India Chembiotek Research International Pvt. Ltd., Salt Lake City, Kolkata-700 091, India 10.3762/bjoc.4.52 Abstract Quinoline and naphthalene-based

• value and did not form any excimer upon complexation with the same acids under similar conditions. This established the role of quinoline ring nitrogen in binding with the acids. Keywords: carboxylic acid recognition; excimer emission; naphthalene; quinoline; Introduction The sensing and monitoring of

• report here an alternative naphthalene-based receptor 2 (Figure 1), where quinoline has been replaced by naphthalene keeping all the other hydrogen bonding groups fixed. The key in all the designs is the appropriate flexible ether linkage to hold the fluorophore probes viz. quinoline and naphthalene in