A survey of chiral hypervalent iodine reagents in asymmetric synthesis

• Soumen Ghosh,
• Suman Pradhan and
• Indranil Chatterjee

Beilstein J. Org. Chem. 2018, 14, 1244–1262, doi:10.3762/bjoc.14.107

• plausible mechanism and transition-state model 27 for the formation of the major isomer through the attack of the carboxylic acid group to the ipso position of the naphthol ring from the less sterically hindered Re-face of the substrate 25. It is worth mentioning that very recently they have introduced a

• spirocyclization of naphthol carboxylic acid [34]. Later Birman et al. reported a new variation of a chiral I(V) reagent, namely 2-(o-iodoxyphenyl)oxazoline derivative 28 [35]. The reagent was applied to an asymmetric [4 + 2] Diels–Alder dimerization of phenolic derivatives 29 to construct tricyclic derivatives 30

• a high level of enantioselectivity. Naphthol derivatives 31 were converted to spirocyclic lactones 32 in the presence of m-CPBA as co-oxidant for the in situ generation of the I(III) catalyst. Secondary n–π* and/or hydrogen-bonding interactions of the catalyst ensured remarkable enantioselectivities

One hundred years of benzotropone chemistry

• Arif Dastan,
• Haydar Kilic and
• Nurullah Saracoglu

Beilstein J. Org. Chem. 2018, 14, 1120–1180, doi:10.3762/bjoc.14.98

• afforded 2,4-dinitro-1-naphthol (297) [175] (Scheme 49). Yoshioka’s group studied the photochemical behavior of benzotropolone 241 (Scheme 49) [176]. Irradiation of a dilute solution of 241A in methanol with Pyrex-filtered light led to the formation of l-hydroxy-6,7-benzobicyclo[3.2.0]hepta-3,6-dien-2-one

Mannich base-connected syntheses mediated by ortho-quinone methides

• Petra Barta,
• Ferenc Fülöp and
• István Szatmári

Beilstein J. Org. Chem. 2018, 14, 560–575, doi:10.3762/bjoc.14.43

• synthesis of 1-aminobenzyl-2-naphthol starting from ammonia, benzaldehyde and 2-naphthol. This protocol is known as Betti reaction and the compound formed as Betti base [7][8][9]. Several examples have been published to extend the reaction and to synthesize varied substituted aminonaphthol derivatives [10

• and the aldehyde yields a Schiff base and then the latter reacts with 2-naphthol in the second nucleophilic addition step. The other theory assumes the formation of an ortho-quinone methide (o-QM) intermediate by the reaction of 2-naphthol and benzaldehyde. Re-aromatization, the driving force of the

• -aminoalkyl-2-naphthol derivatives by a simple amide hydrolysis. The mechanism of the Mannich reaction is depicted in Scheme 1. First, the reaction between the aldehyde and 2-naphthol, induced by the catalyst, leads to the generation of o-QM intermediate 3 that reacts further with the amide component to form

Recent developments in the asymmetric Reformatsky-type reaction

• Hélène Pellissier

Beilstein J. Org. Chem. 2018, 14, 325–344, doi:10.3762/bjoc.14.21

• alcohols and BINOL (1,1’-bi-2-naphthol) derivatives, ligand 53 was selected as optimal ligand when used at a stoichiometric amount in THF at −40 °C. As shown in Scheme 21, the corresponding fluorinated chiral β-amino alcohol 54 was formed in both moderate yield (60%) and enantioselectivity (37% ee

Aminomethylation/hydrogenolysis as an alternative to direct methylation of metalated isoquinolines – a novel total synthesis of the alkaloid 7-hydroxy-6-methoxy-1-methylisoquinoline

• Benedikt C. Melzer,
• Jan G. Felber and
• Franz Bracher

Beilstein J. Org. Chem. 2018, 14, 130–134, doi:10.3762/bjoc.14.8

• phenolic product 6 in high yield with unchanged N,N-dimethylaminomethyl group. The same result was obtained at high pressure (40 bar) and upon addition of formic acid for accelerating hydrogenolysis [21]. Obviously, and in contrast to earlier reports on related naphthol Mannich bases [20], the benzylamine

Vinylphosphonium and 2-aminovinylphosphonium salts – preparation and applications in organic synthesis

• Anna Kuźnik,
• Roman Mazurkiewicz and
• Beata Fryczkowska

Beilstein J. Org. Chem. 2017, 13, 2710–2738, doi:10.3762/bjoc.13.269

• 1-nitroso-2-naphthol or 2-nitroso-1-naphthol leading to 1,4-benzoxazine derivatives was reported. The addition of triarylphosphine to an acetylenic ester followed by protonation of the adduct by the naphthol derivative and the further attack of the resulting naphtholate anion on the β-position of

• )vinylphosphonium salts. Synthesis of 1,4-benzoxazine derivatives from acetylenedicarboxylates, phosphines, and 1-nitroso-2-naphthol or 2-nitroso-1-naphthol in the intramolecular Wittig-like cyclization. Synthesis of vinylphosphonium salts by reaction of α-silyl ylides with aldehydes [17]. Synthesis of 2-(N

Chiral phase-transfer catalysis in the asymmetric α-heterofunctionalization of prochiral nucleophiles

• Johannes Schörgenhumer,
• Maximilian Tiffner and
• Mario Waser

Beilstein J. Org. Chem. 2017, 13, 1753–1769, doi:10.3762/bjoc.13.170

• -worker reported the use of phase-transfer catalysts to carry out the dearomatization of phenol and naphthol derivatives 25 via ortho-hydroxylation to obtain the highly-functionalized targets 26 [119]. Hereby oxaziridines 23 were found to be the best-suited hydroxylating agents. Unfortunately, the

The chemistry and biology of mycolactones

• Matthias Gehringer and
• Karl-Heinz Altmann

Beilstein J. Org. Chem. 2017, 13, 1596–1660, doi:10.3762/bjoc.13.159

Interactions between photoacidic 3-hydroxynaphtho[1,2-b]quinolizinium and cucurbit[7]uril: Influence on acidity in the ground and excited state

• Jonas Becher,
• Daria V. Berdnikova,
• Darinka Dzubiel,
• Heiko Ihmels and
• Phil M. Pithan

Beilstein J. Org. Chem. 2017, 13, 203–212, doi:10.3762/bjoc.13.23

• ][34]. The change of acidity, however, depends on the actual complex structure. For example, it was demonstrated in a comparative study of 2-naphthol and a hydroxyflavylium derivative that the ESPT is suppressed upon complexation with CB[7] if the hydroxy functionality is embedded deeply in the host

• hydroxyphenylbenzimidazole and a topotecan derivative increases from 2 to 4 [32] and from −3 to 6 [31], respectively, upon migration from water solution into CB[7]. In contrast, it was demonstrated that the photoacidity of 2-naphthol is completely suppressed when it is complexed to CB[7] because the hydroxy functionality is

The in situ generation and reactive quench of diazonium compounds in the synthesis of azo compounds in microreactors

• Faith M. Akwi and
• Paul Watts

Beilstein J. Org. Chem. 2016, 12, 1987–2004, doi:10.3762/bjoc.12.186

• -naphthol. The method boasts of shorter reaction times [4] with high yields (Scheme 2). Mirjalili et al. also used silica supported boron trifluoride and was able to carry out diazotization at room temperature [5] after they discovered that the diazonium salts obtained were stable at room temperature even

• in situ azo coupling to 2-naphthol (18) within LTF-MS microreactors was investigated. Although various groups have investigated similar reactions in microreactors, to the best of our knowledge, there is no detailed study combining the effect of pH, temperature and flow rate on the azo coupling

• synthesis and to see if the size effect had any major implication on the reaction performance. Results and Discussion Azo coupling reaction in the synthesis of 1-((2,4-dimethylphenyl)azo)naphthalen-2-ol in LTF-MS microreactors In an effort to exemplify the azo coupling of phenols as well as naphthol

Cross-linked cyclodextrin-based material for treatment of metals and organic substances present in industrial discharge waters

• Élise Euvrard,
• Nadia Morin-Crini,
• Coline Druart,
• Justine Bugnet,
• Bernard Martel,
• Cesare Cosentino,
• Virginie Moutarlier and
• Grégorio Crini

Beilstein J. Org. Chem. 2016, 12, 1826–1838, doi:10.3762/bjoc.12.172

• cationic dyes. Zhang et al. [4] studied the removal of cobalt and 1-naphthol onto magnetic nanoparticles containing cyclodextrin and iron and Yang et al. [5] proposed a new nanocomposite adsorbent for the simultaneous removal of organic and inorganic substances from water. Here, we propose to use a single

Selected synthetic strategies to cyclophanes

• Sambasivarao Kotha,
• Mukesh E. Shirbhate and
• Gopalkrushna T. Waghule

Beilstein J. Org. Chem. 2015, 11, 1274–1331, doi:10.3762/bjoc.11.142

• ) under basic conditions to generate compound 42 which was further subjected to a Glaser–Eglinton coupling to deliver cyclophane 43 (Scheme 5). A derivative of compound 43 was used as a host for compounds such as 6-nitro-2-naphthol, stilbene derivatives and serotonin mimics. This paper depicts the edge

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

• either a Sc(OTf)3–3,3′-bis(diethylaminomethyl)-1,1′-bi-2-naphthol complex (85) or Cu(OTf)2–(S,S)-2,2′-isopropylidene-bis(4-tert-butyl-2-oxazoline) complex (86) (Figure 6). The latter bis(oxazoline) and its derivatives have become common chiral ligands in Lewis acid-mediated reactions [179]. The Evans

Matsuda–Heck reaction with arenediazonium tosylates in water

• Ksenia V. Kutonova,
• Marina E. Trusova,
• Andrey V. Stankevich,
• Pavel S. Postnikov and
• Victor D. Filimonov

Beilstein J. Org. Chem. 2015, 11, 358–362, doi:10.3762/bjoc.11.41

• reaction mixture was heated to 75 °C under stirring by using a microwave reactor in open-vessel mode with a power of 50 W. The conversion of ADT was monitored every minute with a diazonium test with 2-naphthol. When the diazonium test was negative, the reaction mixture was cooled and in the case of solid

Synthetic strategies for the fluorescent labeling of epichlorohydrin-branched cyclodextrin polymers

• Milo Malanga,
• Mihály Bálint,
• István Puskás,
• Kata Tuza,
• Tamás Sohajda,
• László Jicsinszky,
• Lajos Szente and
• Éva Fenyvesi

Beilstein J. Org. Chem. 2014, 10, 3007–3018, doi:10.3762/bjoc.10.319

• polymer leads to compounds with enhanced spectroscopic properties, but it has been rarely described. Zohrehvand and Evans reported the synthesis, characterization and fluorescence studies of a water-soluble 2-naphthol-containing β-CD-epichlorohydrin copolymer [16], but in this case the fluorophore is

Photorelease of phosphates: Mild methods for protecting phosphate derivatives

• Sanjeewa N. Senadheera,
• Abraham L. Yousef and
• Richard S. Givens

Beilstein J. Org. Chem. 2014, 10, 2038–2054, doi:10.3762/bjoc.10.212

• favored by aqueous-based solvents that serve both as a proton donor and an acceptor to the conjugate base generated from the chromophore’s triplet state heterolytic cleavage of the leaving group. The dual behavior of H2O is manifest in accepting a proton from the naphthol OH while simultaneously solvating

• energy of the naphthyl ketone platform or the disruption of both aromatic rings for the 1,5 substituted analog 27 whereas only one ring is involved for the 1,4 substituted derivative [19]. Both of the contributing components of the 2,6 pattern, 2-naphthol (ET = 60.2 kcal/mol) and 2-acetylnaphthalene (ET

• = 59.5 kcal/mol) are higher energy contributors than the same two components of the 1,4 and 1,5 patterns, 1-naphthol (ET = 58.6 kcal/mol) and 1-acetylnaphthalene (ET = 56.4 kcal/mol) [10][11]. Of the two motifs, the 1,4 arrangement has the lower energy triplet. Yet the 2,6 pattern with the higher triplet

Homochiral BINOL-based macrocycles with π-electron-rich, electron-withdrawing or extended spacing units as receptors for C₆₀

• Marco Caricato,
• Silvia Díez González,
• Idoia Arandia Ariño and
• Dario Pasini

Beilstein J. Org. Chem. 2014, 10, 1308–1316, doi:10.3762/bjoc.10.132

• protocol for the preparation of several chiral macrocycles incorporating BINOL (1,1′-bi-2-naphthol) units, through the formation of bridging ester functionalities, which ensure chemical inertness for the purposes of supramolecular sensing, recognition, or self-assembly. We have shown their application in

Synthesis of fluorescent (benzyloxycarbonylamino)(aryl)methylphosphonates

• Michał Górny vel Górniak,
• Anna Czernicka,
• Piotr Młynarz,
• Waldemar Balcerzak and
• Paweł Kafarski

Beilstein J. Org. Chem. 2014, 10, 741–745, doi:10.3762/bjoc.10.68

• is far more difficult as shown by reaction of chloride 5 with 2-naphthol providing compound 7g. This reaction was carried out in chloroform in the presence of triethylamine. Fluorescence Fluorescence of the representative examples of the obtained compounds was measured upon irradiation of two

Conformational analysis and intramolecular interactions in monosubstituted phenylboranes and phenylboronic acids

• Josué M. Silla,
• Rodrigo A. Cormanich,
• Roberto Rittner and
• Matheus P. Freitas

Beilstein J. Org. Chem. 2013, 9, 1127–1134, doi:10.3762/bjoc.9.125

• for 2-monohalogen substituted phenols [12]. In fact, organic fluorine has been found to hardly ever participate in hydrogen bonding [13], despite the appearance of this interaction in 8-fluoro-4-methyl-1-naphthol [14], 2'-fluoroflavonols [15], 2-fluorobicyclo[2.2.1]heptan-7-ols [16] and 2

Synthesis of meso-substituted dihydro-1,3-oxazinoporphyrins

• Satyasheel Sharma and
• Mahendra Nath

Beilstein J. Org. Chem. 2013, 9, 496–502, doi:10.3762/bjoc.9.53

• condensation–cyclization reaction of 5-(4-aminophenyl)-10,15,20-triphenylporphyrin (1) with α- or β-naphthol and formaldehyde in THF under reflux. After reaction with Zn(OAc)2·2H2O in CHCl3/MeOH mixture, the free-base naphthoxazinoporphyrins 14 and 16 underwent zinc insertion to afford zinc (II) dihydro-1,3

Palladium-catalyzed C–N and C–O bond formation of N-substituted 4-bromo-7-azaindoles with amides, amines, amino acid esters and phenols

• Rajendra Surasani,
• Dipak Kalita,
• A. V. Dhanunjaya Rao and
• K. B. Chandrasekhar

Beilstein J. Org. Chem. 2012, 8, 2004–2018, doi:10.3762/bjoc.8.227

• structurally diverse phenols. Results are summarized in Table 8. The C–O-bond formation was established with good yields with phenol derivatives and 1-naphthol (Table 8, entries 1–3). Moreover, the outcome of the reaction strongly depended on the electronic character of the appropriate phenol (Table 8). The

Arylglycine-derivative synthesis via oxidative sp³ C–H functionalization of α-amino esters

• Zhanwei Xu,
• Xiaoqiang Yu,
• Xiujuan Feng and
• Ming Bao

Beilstein J. Org. Chem. 2012, 8, 1564–1568, doi:10.3762/bjoc.8.178

• ethyl 2-(disubstituted amino)acetates. The results are reported in the current work (Scheme 2, reaction 2). In our initial studies, the reaction of 2-naphthol (1a) with ethyl 2-morpholinoacetate (2a) was chosen as a model for optimizing the reaction conditions. The results are shown in Table 1. The

• reaction of 5 with 2-naphthol may have occurred to generate the coupling product 3a. The generated 3-chlorobenzoate anion acted as a proton acceptor. In conclusion, a new strategy for the functionalization of sp3 C–H bonds of amino esters was successfully applied to the coupling reaction of ethyl 2

Conformational analysis, stereoelectronic interactions and NMR properties of 2-fluorobicyclo[2.2.1]heptan-7-ols

• Fátima M. P. de Rezende,
• Marilua A. Moreira,
• Rodrigo A. Cormanich and
• Matheus P. Freitas

Beilstein J. Org. Chem. 2012, 8, 1227–1232, doi:10.3762/bjoc.8.137

• ]. However, 2-fluorophenol (4) shows a through-space (TS) coupling constant 1TSJF,H(O) of ca. 5 Hz, which has been ascribed as being due to the overlap of electronic clouds between F and hydroxy H rather than to hydrogen bonding [8], while the corresponding SSCC in 8-fluoro-4-methyl-1-naphthol, which

Cationic gold(I) axially chiral biaryl bisphosphine complex-catalyzed atropselective synthesis of heterobiaryls

• Tetsuro Shibuya,
• Kyosuke Nakamura and
• Ken Tanaka

Beilstein J. Org. Chem. 2011, 7, 944–950, doi:10.3762/bjoc.7.105

• carried out under an atmosphere of argon or nitrogen in oven-dried glassware with magnetic stirring. (2-Methoxymethoxynaphthalen-1-yl)propynoic acid naphthalen-2-yl ester (1c): To a stirred solution of 3-[2-(methoxymethoxy)-1-naphthalenyl]-2-propynoic acid [48] (0.256 g, 1.00 mmol), 2-naphthol (0.159 g

Stereogenic boron in 2-amino-1,1-diphenylethanol-based boronate–imine and amine complexes

• Sebastian Schlecht,
• Walter Frank and
• Manfred Braun

Beilstein J. Org. Chem. 2011, 7, 615–621, doi:10.3762/bjoc.7.72

• known procedure [20], the amino alcohol 5 was readily accessible from methyl glycinate hydrochloride by the reaction with excess phenylmagnesium bromide. Subsequent condensation with 1-formyl-2-naphthol (6) gave the imine 7 in 87% yield (Scheme 2). In order to generate the boronate–imine complex 8, the