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

• the reaction medium. As for phenol derivatives, their lower reactivities led to even further decreased yields (Scheme 38b). Interestingly, while the introduction of the SOCF3 moiety occurred selectively on the nitrogen atom for amines, only the C-trifluoromethylsulfinylated products were isolated when

• performing the reaction on phenol derivatives. Such products were probably obtained through an O-trifluoromethylsulfinylation step, followed by a rearrangement. As for the mechanism of the reaction, we proposed a pathway similar to the one we previously described for the trifluoromethylsulfenylation of

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

• consisted in the β-elimination of the phenol molecule (Scheme 8) [16]. A similar reaction using β-phenoxyethylphosphonium salts 9 derived from benzyldiphenylphosphine or dibenzylphenylphosphine required an alkaline environment and gave the expected vinylphosphonium salts 10 in good yields (Scheme 9) [16

• ]. The use of pyrocatechol or pyrogallol as reagents in reactions with the analogous mechanism resulted in the formation of mono-, di-, and tricyclic reaction products of phenol derivatives with one or two vinylphosphonium salt molecules (Scheme 62 and Scheme 63) [75]. In a similar reaction with 2

• subsequent isomerization of intermediate allylphosphonium salts. Alkylation of triphenylphosphine with vinyl triflates in the presence of (Ph3P)4Pd. Mechanism of alkylation of triphenylphosphine with vinyl triflates in the presence of (Ph3P)4Pd as catalyst. β-Elimination of phenol from β

Binding abilities of a chiral calix[4]resorcinarene: a polarimetric investigation on a complex case of study

• Marco Russo and
• Paolo Lo Meo

Beilstein J. Org. Chem. 2017, 13, 2698–2709, doi:10.3762/bjoc.13.268

• (with methyl groups in place of the n-propyl groups at the methylene bridges), an average pKa value as large as 6.3 ± 1 per arene subunit has been estimated from titration curves, under the hypothesis that the four subunits behave equivalently [32]. In the latter case, the deprotonation of phenol groups

• progressive deprotonation, and the consequent presence of an increasing negative charge, are reasonable. It is worth recalling here that the cone conformation of the resorcinarene scaffold is stabilized by the possible formation of a hydrogen-bond network between pairs of phenol groups on adjacent arene units

• bond system. Hydrogen bonding is likely enforced by deprotonation of a phenol group, due to enhanced Coulomb interaction with ammonium groups. Moreover, protonation of the nitrogen atom makes it a further chiral centre, which contributes to the overall optical activity of the system. Then, both the

Phosphonic acid: preparation and applications

• Charlotte M. Sevrain,
• Mathieu Berchel,
• Hélène Couthon and
• Paul-Alain Jaffrès

Beilstein J. Org. Chem. 2017, 13, 2186–2213, doi:10.3762/bjoc.13.219

• cleavage. These results indicated that the mesomeric effect induced by the phenol function likely explained the difference of stability of compounds 23 and diethyl 3-hydroxyphenylphosphonate in refluxing HCl 35% solution. Of note, if classical heating at 100 °C is usually employed some reaction under

• dialkyl phosphonates (Figure 8). For the hydrolysis of diphenyl phosphonate it is likely that after protonation of the phosphonate, water acts as a nucleophile and subsequently phenol is eliminated (Figure 11). The repetition of this sequence produces phosphonic acid. Of note, the treatment of phosphonate

Novel approach to hydroxy-group-containing porous organic polymers from bisphenol A

• Tao Wang,
• Yan-Chao Zhao,
• Li-Min Zhang,
• Yi Cui,
• Chang-Shan Zhang and
• Bao-Hang Han

Beilstein J. Org. Chem. 2017, 13, 2131–2137, doi:10.3762/bjoc.13.211

• one trialdehyde M3 [22] were employed to react with bisphenol A to produce phenolic-resin porous polymers PPOP-1–PPOP-3 (Scheme 1). It is well-known that the ortho- and para-position of phenol are activated with negative charge for the electrophilic aromatic substitution in consequence of the electron

• -donating effect of the hydroxy group. The positively charged carbonyl group of the aldehyde could be attacked by the electron-rich phenyl ring, thus a carbonyl group can connect two phenol molecules by elimination of a water molecule. As a result, a cross-linked hydroxy-group-containing polymer is

• thermal degradation for PPOPs until when heated up to 300 °C. According to the TGA result of BPA (Supporting Information File 1, Figure S2), the thermal degradation of BPA begins around 180 °C and the evolved products are mainly phenol with one or two benzene rings from investigations of thermal

Preparation of imidazo[1,2-a]-N-heterocyclic derivatives with gem-difluorinated side chains

• Layal Hariss,
• Kamal Bou Hadir,
• Mirvat El-Masri,
• Thierry Roisnel,
• René Grée and
• Ali Hachem

Beilstein J. Org. Chem. 2017, 13, 2115–2121, doi:10.3762/bjoc.13.208

• , respectively. On the other hand, two nucleophilic substitution reactions using phenol and morpholine gave the expected heterocycles 10 and 11 in 73% and 23% yields, respectively. Conclusion In summary, we developed a short and completely regioselective method for the synthesis of imidazo[1,2-a]-N-heterocycles

Intramolecular glycosylation

• Xiao G. Jia and
• Alexei V. Demchenko

Beilstein J. Org. Chem. 2017, 13, 2028–2048, doi:10.3762/bjoc.13.201

• picoloyl group-directed coordination of palladium from the top β-face of the 1,2-dehydro donor 91 to form intermediate 92 (Scheme 21). With softer nucleophiles, such as phenol (ArOH), the nucleophilic attack is directed away from the steric bulk of the palladium to give α-glycosides 93. When the acceptor

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

• and co-workers reported bromination of phenol derivatives, chalcones, 1,3-dicarbonyl compounds using NaBr as bromine source and oxone as oxidant under ball-milling conditions [96]. Within 1 h they could isolate more than 90% of mono or poly-brominated products of phenol and 1,3-dicarbonyl compounds

Enzymatic synthesis of glycosides: from natural O- and N-glycosides to rare C- and S-glycosides

• Jihen Ati,
• Pierre Lafite and
• Richard Daniellou

Beilstein J. Org. Chem. 2017, 13, 1857–1865, doi:10.3762/bjoc.13.180

• retaining mechanism). In the case of O-GTs, the nucleophile is an alcohol or a phenol (carbohydrates, serine, threonine, …), whereas in N-GTs, the nature of the nitrogen-containing group is more diverse (amines, amides, guanidine or even indoles) [12]. S- and C-GTs follow a similar mechanism with the

Selective enzymatic esterification of lignin model compounds in the ball mill

• Ulla Weißbach,
• Saumya Dabral,
• Laure Konnert,
• Carsten Bolm and
• José G. Hernández

Beilstein J. Org. Chem. 2017, 13, 1788–1795, doi:10.3762/bjoc.13.173

• group. Initially, it was hypothesized that the presence of a phenolic functionality present in 1f could have inhibited the lipase activity or perhaps caused some degree of denaturation in the enzyme. To test this hypothesis, control experiments using erythro-1a, 2a and CALB in the presence of phenol

• (1.0 equiv) and phenol derivatives (guaiacol, 3-methoxyphenol, etc.) were carried out. In most cases, the presence of the additives had no negative effect on the performance of CALB (for details see Table S2 in Supporting Information File 1). Only the presence of 2,2’-biphenol seemed to have slowed

• were milled (Table 2, entry 3), and formation of phenol was expected as a byproduct of the reaction. Hence, the lower reactivity of 1f could have been a consequence of aggregation of the substrate or possible changes in its conformation. This could have reduced the affinity of CALB for 1f compared to

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

An effective Pd nanocatalyst in aqueous media: stilbene synthesis by Mizoroki–Heck coupling reaction under microwave irradiation

• Carolina S. García,
• Paula M. Uberman and
• Sandra E. Martín

Beilstein J. Org. Chem. 2017, 13, 1717–1727, doi:10.3762/bjoc.13.166

• -diphenylvinyl)phenyl)ethanone (15) [56], and (E)-4-(3,5-dimethoxystyryl)phenol or pterostilbene (19) [60]. Representative procedure for the MW-assisted Stille–Heck coupling reactions Analogously to the procedure described in [47], into a 10 mL MW tube equipped with a magnetic stirring bar, aryl bromide 1a, 1d

Oxidative dehydrogenation of C–C and C–N bonds: A convenient approach to access diverse (dihydro)heteroaromatic compounds

• Santanu Hati,
• Ulrike Holzgrabe and
• Subhabrata Sen

Beilstein J. Org. Chem. 2017, 13, 1670–1692, doi:10.3762/bjoc.13.162

• substituted 2-aminophenol (Scheme 38). Accordingly the reaction is believed to have initiated by the formation of imine intermediate V. The 4-methoxy-TEMPO radical interacted with V and subsequent H-absorption from the phenol moiety afforded phenoxy radical W and 4-methoxy-TEMPOH which gets re-oxidized to the

A novel approach to oxoisoaporphine alkaloids via regioselective metalation of alkoxy isoquinolines

• Benedikt C. Melzer and
• Franz Bracher

Beilstein J. Org. Chem. 2017, 13, 1564–1571, doi:10.3762/bjoc.13.156

• using polyphosphoric acid (Scheme 1). In the course of this cyclization, the methoxy group at C-6 is typically hydrolized to the phenol, subsequent O-methylation gives the 6-methoxy derivatives menisporphine (2) and dauriporphine (3). Recently, Zhang et al. [20] described an alternative approach

Bifunctional organocatalysts for the asymmetric synthesis of axially chiral benzamides

• Ryota Miyaji,
• Yuuki Wada,
• Akira Matsumoto,
• Keisuke Asano and
• Seijiro Matsubara

Beilstein J. Org. Chem. 2017, 13, 1518–1523, doi:10.3762/bjoc.13.151

• analysis of the reaction selectivity (the decrease of the enantiomeric purity of 2b was negligible after a day). Furthermore, the reaction of benzamide 5, bearing a protected phenol, was carried out (Scheme 6). It failed to give the corresponding product 6, indicating the significance of multipoint

• substituted phenols. Reactions of monobrominated substrates. Rotational barriers of substrates and intermediates calculated at the B3YLP/6-31G(d) level of theory. Reaction of substrate with protected phenol. Optimization of conditions.a Supporting Information Supporting Information File 257: Experimental

An improved preparation of phorbol from croton oil

• Alberto Pagani,
• Simone Gaeta,
• Andrei I. Savchenko,
• Craig M. Williams and
• Giovanni Appendino

Beilstein J. Org. Chem. 2017, 13, 1361–1367, doi:10.3762/bjoc.13.133

• of the oil, especially in association to phenol [3]. The extraordinarily obnoxious and vesicant properties of croton oil have fostered studies aimed at the identification of its active principles since the very early developments of organic chemistry. Thus, the first chemical study on croton oil was

Total synthesis of elansolids B1 and B2

• Liang-Liang Wang and
• Andreas Kirschning

Beilstein J. Org. Chem. 2017, 13, 1280–1287, doi:10.3762/bjoc.13.124

• ], which was first reduced at C-25 (Scheme 3). The two diastereoisomers could be separated by chromatography and the stereochemical assignment of the major isomer was based on X-ray crystallographic analysis [7]. Next, Tamao–Fleming oxidation [10] yielded phenol 15. The alkyne was transformed into vinyl

• , 131.8, 128.7, 128.3, 128.1, 124.7, 124.1, 123.7, 113.8, 86.7, 81.3, 73.9, 73.5, 64.9, 55.8, 55.3, 52.9, 46.6, 45.3, 38.0, 33.4, 31.1, 26.3, 24.2, 22.7, 21.3, −3.4, −3.3; HRMS (ESI) m/z: [M + Na]+ calculated for C39H48O3SiNa, 615.3270; found, 615.3270. Synthesis of phenol 15 To a solution of the benzyl

• flash column chromatography gave phenol 15 (96.0 mg, 0.20 mol, 99%) as a colorless solid. Rf = 0.20 (PE/EtOAc 3:1, visualized using an anisaldehyde stain or UV), [α]D20 = +26.1 (c 0.7, CH2Cl2); 1H NMR (400 MHz, CDCl3, CHCl3 = 7.26 ppm) δ 7.31–7.28 (m, 4H), 6.90 (d, J = 8.7 Hz, 2H), 6.86 (d, J = 8.6 Hz

Automating multistep flow synthesis: approach and challenges in integrating chemistry, machines and logic

• Chinmay A. Shukla and
• Amol A. Kulkarni

Beilstein J. Org. Chem. 2017, 13, 960–987, doi:10.3762/bjoc.13.97

• . In the first step, 4-(2-bromoethyl)phenol is converted to its azide derivative by passing it through a glass reactor packed with azide exchange resin (20 equiv) at 70 °C to achieve quantitative yield. MeCN and THF were used as solvents. Dimethoxybenzyl alcohol (in THF) is oxidized to the

• -(2-bromoethyl)phenol can be fixed at a desired set-point using a control valve. This process stream can be preheated at the reaction temperature (70 °C). It can then be passed through the reactor packed with azide exchange resin maintained at the desired temperature using a jacket. The azide exchange

Metal-free hydroarylation of the side chain carbon–carbon double bond of 5-(2-arylethenyl)-3-aryl-1,2,4-oxadiazoles in triflic acid

• Anna S. Zalivatskaya,
• Dmitry S. Ryabukhin,
• Marina V. Tarasenko,
• Alexander Yu. Ivanov,
• Irina A. Boyarskaya,
• Elena V. Grinenko,
• Ludmila V. Osetrova,
• Eugeniy R. Kofanov and
• Aleksander V. Vasilyev

Beilstein J. Org. Chem. 2017, 13, 883–894, doi:10.3762/bjoc.13.89

• and local anesthetic [15], and ataluren finds application for the treatment of fibrosis [16]. Often, oxadiazole derivatives act as inhibitors of bacterial phenylalanyl-tRNA-synthetase [17], phosphodiesterase 4B2 [18], y-secretase [19] and phenol-substituted 1,2,4-oxadiazoles exhibit powerful anti

Transition-metal-catalyzed synthesis of phenols and aryl thiols

• Yajun Liu,
• Shasha Liu and
• Yan Xiao

Beilstein J. Org. Chem. 2017, 13, 589–611, doi:10.3762/bjoc.13.58

• has not been reported. In this review, a brief overview is given of the recent advances in synthetic strategies for both phenols and aryl thiols. Keywords: aryl thiol; C–O bond; C–S bond; phenol; transition metal; Introduction Phenols and aryl thiols serve as both important intermediates in organic

• other hand, the C–H hydroxylation, either with heteroatom-containing directing groups or without directing groups, has provided various methods for the synthesis of phenols. Compared with traditional methods, the transition-metal-catalyzed phenol synthesis has several advantages: broad substrate scope

• scope of functional groups including ether, halo, hydroxy, carboxylic acid and trifluoromethyl groups were well tolerated in their protocol. Even hindered substrates such as 2,6-diisopropyl iodobenzene also afforded the corresponding phenol in satisfying yield. The developed protocol was further applied

3D printed fluidics with embedded analytic functionality for automated reaction optimisation

• Andrew J. Capel,
• Andrew Wright,
• Matthew J. Harding,
• George W. Weaver,
• Yuqi Li,
• Russell A. Harris,
• Steve Edmondson,
• Ruth D. Goodridge and
• Steven D. R. Christie

Beilstein J. Org. Chem. 2017, 13, 111–119, doi:10.3762/bjoc.13.14

• allow a much larger chemical space to be analysed (<200 °C). The formation of a fused polycyclic heterocycle 5 (Scheme 2), from pentafluoropyridine (3) and 2-(methylamino)phenol (4), was chosen as this would generate a more complex optimisation set with two starting materials, the reaction product as

• -(methylamino)phenol (4) to form the corresponding fused polycyclic heterocycle 5. Conditions and limits for the optimisation used in tandem with RD1. Ketone 1 concentration 0.40 mmol/L, semicarbazide concentration 1.20 mmol/L. Supporting Information Supporting Information File 14: General considerations

Stabilization of nanosized titanium dioxide by cyclodextrin polymers and its photocatalytic effect on the degradation of wastewater pollutants

• Tamás Zoltán Agócs,
• István Puskás,
• Erzsébet Varga,
• Mónika Molnár and
• Éva Fenyvesi

Beilstein J. Org. Chem. 2016, 12, 2873–2882, doi:10.3762/bjoc.12.286

• decomposition [27][28]. Recently, various photocatalysts modified by CDs have been described. For instance, reduced graphene oxide/β-CD/titanium dioxide showed enhanced removal of phenol and Cr(VI) [29], graphene nanosheets with self-assembled nanolayer of TiO2 stabilized by β-CD resulted in improved

cis-Diastereoselective synthesis of chroman-fused tetralins as B-ring-modified analogues of brazilin

• Dimpee Gogoi,
• Runjun Devi,
• Pallab Pahari,
• Bipul Sarma and
• Sajal Kumar Das

Beilstein J. Org. Chem. 2016, 12, 2816–2822, doi:10.3762/bjoc.12.280

• convenient Brønsted acid-catalyzed, metal-free, stereoselective synthesis of 6a,7,8,12b-tetrahydro-6H-naphtho[2,1-c]chromen-6a-ols as B-ring-modified analogues of brazilin using starting materials derived from inexpensive 1-tetralone and phenol derivatives. Our worries concerning the formation cis–trans

From betaines to anionic N-heterocyclic carbenes. Borane, gold, rhodium, and nickel complexes starting from an imidazoliumphenolate and its carbene tautomer

• Ming Liu,
• Jan C. Namyslo,
• Martin Nieger,
• Mika Polamo and
• Andreas Schmidt

Beilstein J. Org. Chem. 2016, 12, 2673–2681, doi:10.3762/bjoc.12.264

• .12.264 Abstract The mesomeric betaine imidazolium-1-ylphenolate forms a borane adduct with tris(pentafluorophenyl)borane by coordination with the phenolate oxygen, whereas its NHC tautomer 1-(2-phenol)imidazol-2-ylidene reacts with (triphenylphosphine)gold(I) chloride to give the cationic NHC complex [Au

• bond angle of 177.35(8)° was found. However, in contrast to other gold complexes, the two imidazole rings are not coplanar [38]. In addition, the imidazole and the phenol rings are twisted about −119.84(16)° (C5–N1–C6–C7) relative to the imidazole ring. Two Au complexes are connected via one halide

• ppm) [29][39], and other Rh complexes [40][41]. Correspondingly the phenol proton signals of the three geometrically non-equivalent ligands appear at different resonance frequencies. Thus, the three unsubstituted ortho positions of the phenolate moieties are detectable at 6.93–6.97 ppm (overlapped

A new paradigm for designing ring construction strategies for green organic synthesis: implications for the discovery of multicomponent reactions to build molecules containing a single ring

• John Andraos

Beilstein J. Org. Chem. 2016, 12, 2420–2442, doi:10.3762/bjoc.12.236

• containing one asymmetric feature, namely the electrophilic carbonyl group. This molecule is made industrially from precursors that already have the 6-membered ring preformed [132]. Example routes include dehydrogenation of cyclohexanol, which in turn is made either by catalytic hydrogenation of phenol