Rapid transformation of sulfinate salts into sulfonates promoted by a hypervalent iodine(III) reagent

• Elsa Deruer,
• Vincent Hamel,
• Samuel Blais and
• Sylvain Canesi

Beilstein J. Org. Chem. 2018, 14, 1203–1207, doi:10.3762/bjoc.14.101

• Discussion Oxidative sulfonate production methods employing strong oxidizing agents such as chlorine have been previously reported [30]. More recently, a mild and efficient method enabling the production of aromatic sulfonates using phenols and iodine was developed [31][32]. This method uses methanol as a

• solvent and appears to be selective for phenols; only two primary alcohol examples were produced in 63–67% yield in the presence of a strong base. A radical pathway from the alkoxide species was proposed by the authors as an explanation for the phenol selectivity under weakly basic conditions in the

• compatible in presence of phenols. We hypothesized that the mechanism would initially involve iodane activation of the sulfur lone pair leading to 2. Elimination of the iodane would subsequently produce the sulfonium ion 3, which could be trapped by an alcohol nucleophile leading to sulfonate 4 (Scheme 1

On the design principles of peptide–drug conjugates for targeted drug delivery to the malignant tumor site

• Eirinaios I. Vrettos,
• Gábor Mező and
• Andreas G. Tzakos

Beilstein J. Org. Chem. 2018, 14, 930–954, doi:10.3762/bjoc.14.80

One-pot synthesis of diaryliodonium salts from arenes and aryl iodides with Oxone–sulfuric acid

• Natalia Soldatova,
• Pavel Postnikov,
• Olga Kukurina,
• Viktor V. Zhdankin,
• Akira Yoshimura,
• Thomas Wirth and
• Mekhman S. Yusubov

Beilstein J. Org. Chem. 2018, 14, 849–855, doi:10.3762/bjoc.14.70

• the generation of iodine(III) species in the oxidation of phenols [43]. In the present work, we report the development of a reliable and convenient procedure for the preparation of diaryliodonium bromides using Oxone in the presence of sulfuric acid. Results and Discussion After having investigated

Enantioselective dioxytosylation of styrenes using lactate-based chiral hypervalent iodine(III)

• Morifumi Fujita,
• Koki Miura and
• Takashi Sugimura

Beilstein J. Org. Chem. 2018, 14, 659–663, doi:10.3762/bjoc.14.53

• iodine reagents using a lactate motif has been employed for several types of oxidation reaction since we first reported this procedure [18]. Enantioselective oxidative transformations include the dearomatization of phenols [19][20][21][22][23][24], α-functionalization of carbonyl compounds [25][26][27

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

• . This results in differences in both the formation and stability of o-QM. Grimaud et al. synthesized Mannich bases starting from N-benzylpiperazine, various aldehydes and substituted phenols [63]. The intermediate Mannich adducts 8a–i were then reacted with 5,5-dimethylcyclohexane-1,3-dione or 1-methyl

• ortho-amidoalkylation of phenols in which a tandem Knoevenagel condensation occurs through o-QM followed by the formation of an unstable oxazine intermediate [64]. Later, the same research group published a similar reaction extended by various lactams carried out in trifluoroacetic acid in water [65

• wide range of novel 2-[(benzo[d]thiazol-2-ylamino(phenyl)methyl]phenols 10a–m [66]. In their study, 2-amino-1,3-benzothiazoles, various aldehydes and substituted phenols were reacted in the presence of ZnCl2 as catalyst. Reactions of o-QMs formed by Mannich bases As the formation of Mannich bases can

Functionalization of N-arylglycine esters: electrocatalytic access to C–C bonds mediated by n-Bu₄NI

• Mi-Hai Luo,
• Yang-Ye Jiang,
• Kun Xu,
• Yong-Guo Liu,
• Bao-Guo Sun and
• Cheng-Chu Zeng

Beilstein J. Org. Chem. 2018, 14, 499–505, doi:10.3762/bjoc.14.35

• terminal oxidants [14]. The protocol was also extended to reactions with 2-alkylquinoline [15] and phenols [16] using O2 and di-tert-butyl peroxide (DTBP) as oxidant, respectively (Scheme 1). A CuCl-catalyzed oxidative cross coupling of glycine derivatives with indoles has been developed by Hou et al

One-pot preparation of 4-aryl-3-bromocoumarins from 4-aryl-2-propynoic acids with diaryliodonium salts, TBAB, and Na₂S₂O₈

• Teppei Sasaki,
• Katsuhiko Moriyama and
• Hideo Togo

Beilstein J. Org. Chem. 2018, 14, 345–353, doi:10.3762/bjoc.14.22

• ], antitumor [1], antiasthmatic [12], and antiviral including anti-HIV [13][14]. Comprehensive synthetic studies of coumarins and their derivatives have been carried out [15][16]. Typically, coumarins are prepared by the acid-catalyzed condensation of 2-alkynoic acids and phenols or the condensation of β

• -ketoesters and phenols (the Pechmann condensation) [17]. Recent studies for the metal-catalyzed reactions for the synthesis of the coumarin skeleton are as follows: the Yb(OTf)3-catalyzed microwave irradiation of phenols and propynoic acids [18], the Pd(OAc)2-catalyzed oxidative cyclocarbonylation of 2

• acid-catalyzed reaction of phenols and propynoic acids [22] and the (−)-riboflavin-catalyzed photochemical reaction of cinnamic acids [23] were reported recently. Moreover, the use of radical cyclization for the construction of the coumarin skeleton has become widespread. Examples include the radical

5-Aminopyrazole as precursor in design and synthesis of fused pyrazoloazines

• Ranjana Aggarwal and
• Suresh Kumar

Beilstein J. Org. Chem. 2018, 14, 203–242, doi:10.3762/bjoc.14.15

• coupled with various phenols 152 at the more reactive 7-position under mild reaction conditions in presence of K2CO3 in acetic acid/DMF to give pyrazolo[1,5-a]pyrimidine derivative 153. Various aromatic amines 154 were then coupled at 5-postion under Buchwald–Hartwig conditions to get the desired 5

Progress in copper-catalyzed trifluoromethylation

• Guan-bao Li,
• Chao Zhang,
• Chun Song and
• Yu-dao Ma

Beilstein J. Org. Chem. 2018, 14, 155–181, doi:10.3762/bjoc.14.11

• catalytic amount of copper salt was required in this reaction. The hydrogens on the ortho and para positions of phenols have higher reactivity. Thus, undesired side reactions were often involved in the trifluoromethylation of less substituted phenols, including oxidative dimerization and oligomerization

• . Although phenols were widely used building blocks in bioactive compounds, only a few examples introducing a CF3 have been reported. In 2015, the group of Hamashima [52] achieved a direct C–H trifluoromethylation of phenol derivatives with high regioselectivity. The CF3 was selectively incorporated into the

Volatiles from the tropical ascomycete Daldinia clavata (Hypoxylaceae, Xylariales)

• Tao Wang,
• Kathrin I. Mohr,
• Marc Stadler and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2018, 14, 135–147, doi:10.3762/bjoc.14.9

• limits [36]. Their origin by biomethylation of the corresponding phenols is frequently discussed, but the de novo formation of compounds 14 and 15 without administration of the corresponding phenols has not been reported before. Volatiles from Daldinia clavata identified by synthesis Several other

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

• phenols. Mono- and dichlorination of carbon acids. Monochlorination of (N-aryl-N-hydroxy)acylacetamides. Examples of the synthesis of heterocycles fused with β-lactams through a chlorination/cyclisation process. Enantioselective chlorination of β-ketoesters and oxindoles. Enantioselective chlorination 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

• for the synthesis of 4-methoxycarbonylcoumarins by reaction of dimethyl acetylenedicarboxylate and triphenylphosphine with substituted phenols. The vinyltriphenylphosphonium salt 106 that is formed as an intermediate product was attacked by the nucleophilic carbon atom of the phenolate anion, which

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

• , benzaldehydes and electron-rich phenols in presence of 5 mol % of POPI, afforded near quantitative yield of chromene derivatives within 20 min (Scheme 40). Similarly, various benzaldehydes with electron-withdrawing groups at the o/p-position accelerated the reaction and electron-donating groups slowed that down

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

• down the acetylation of erythro-1a. A plausible explanation could be the nature of the 2,2’-biphenol moiety, which could have acted as a ligand interfering with the enzyme. The resilience of CALB to phenols is in agreement with the high reactivity observed when phenyl acetate (2c), erythro-1a and CALB

• the lower reactivity towards the esterification of the substrate containing a phenolic substituent 1f. Although it is known that lignin samples contain units bearing aromatic phenols, these phenolic fragments are mostly located at the terminal sides of the biopolymer. Therefore, enzymatically

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

• dearomatization of phenols and naphthols. Ishihara’s ammonium salt-catalysed oxidative cycloetherification. Chiral phase-transfer-catalysed α-sulfanylation reactions. Chiral phase-transfer-catalysed α-trifluoromethylthiolation of β-ketoesters 1. Chiral phase-transfer-catalysed α-amination of β-ketoesters 1 using

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

• the presence of silver oxide), phenols 4 and 5 were converted into the alkaloids 2 and 3 in 33 and 49% yields (Scheme 9). In accordance to Kunitomo’s observations, the isomeric methoxy compounds 18 and 19 were obtained as byproducts in significant yields (Scheme 9). In order to find a more convenient

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

• 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

Urea–hydrogen peroxide prompted the selective and controlled oxidation of thioglycosides into sulfoxides and sulfones

• Adesh Kumar Singh,
• Varsha Tiwari,
• Kunj Bihari Mishra,
• Surabhi Gupta and
• Jeyakumar Kandasamy

Beilstein J. Org. Chem. 2017, 13, 1139–1144, doi:10.3762/bjoc.13.113

• available, inexpensive and nontoxic. The application of UHP as oxidant is well explored in various solution- as well as solid-phase organic syntheses [25][26][27][28]. In fact, we have recently reported the oxidation of arylboronic acids into corresponding phenols by using UHP as a selective oxidizing agent

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

• Yajun Liu Shasha Liu Yan Xiao College of Life Science and Medicine, Dalian University of Technology, Panjin 124221, China Department of Pharmaceutical Engineering, Shenyang Pharmaceutical University, Shenyang 110016, China 10.3762/bjoc.13.58 Abstract Phenols and aryl thiols are fundamental

• building blocks in organic synthesis and final products with interesting biological activities. Over the past decades, substantial progress has been made in transition-metal-catalyzed coupling reactions, which resulted in the emergence of new methods for the synthesis of phenols and aryl thiols. Aryl

• halides have been extensively studied as substrates for the synthesis of phenols and aryl thiols. In very recent years, C–H activation represents a powerful strategy for the construction of functionalized phenols directly from various arenes. However, the synthesis of aryl thiols through C–H activation

Studies directed toward the exploitation of vicinal diols in the synthesis of (+)-nebivolol intermediates

• Runjun Devi and
• Sajal Kumar Das

Beilstein J. Org. Chem. 2017, 13, 571–578, doi:10.3762/bjoc.13.56

• nucleophilic attack of the phenolic hydroxy group; instead it reacted with water during the work-up process. This different outcome of this reaction compared to Borhan’s results might be attributed to the lower nucleophilicity of phenols compared to alcohols. Previously, Panda and co-worker converted

Synthesis of 1-indanones with a broad range of biological activity

• Marika Turek,
• Dorota Szczęsna,
• Marek Koprowski and
• Piotr Bałczewski

Beilstein J. Org. Chem. 2017, 13, 451–494, doi:10.3762/bjoc.13.48

• . Fluoroorganic compounds play a significant role as very effective therapeutics, and for this reason, Prakash, Olah et al. synthesized in 2010 trifluoromethyl-substituted arylpropanoic acids 12, 1-indanones 13 and dihydrocoumarins 14 (Scheme 5) [17]. These products have been obtained by utilizing arenes/phenols

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

• different phenols. Commercially available 1-tetralone (8) could be the starting materials to obtain compound 7. One major synthetic challenge associated with 5 is the preferential formation of the cis-fused [6,6] ring system over the corresponding trans-isomer. While the stereochemical obligation makes sure

A versatile route to polythiophenes with functional pendant groups using alkyne chemistry

• Xiao Huang,
• Li Yang,
• Rikard Emanuelsson,
• Jonas Bergquist,
• Maria Strømme,
• Martin Sjödin and
• Adolf Gogoll

Beilstein J. Org. Chem. 2016, 12, 2682–2688, doi:10.3762/bjoc.12.265

• synthesis exclude the use of pendant groups featuring electrophilic or nucleophilic functional moieties, such as esters and alkyl halide, or alcohols and phenols. Furthermore, in the case of EDOT-CH2-Cl/Br, the α-hydrogen on the ethylene bridge is acidic and it thus favors β-elimination under basic

Solvent-free, visible-light photocatalytic alcohol oxidations applying an organic photocatalyst

• Martin Obst and
• Burkhard König

Beilstein J. Org. Chem. 2016, 12, 2358–2363, doi:10.3762/bjoc.12.229

• solvent like hydrogen-atom transfer or the formation of byproducts could be excluded. For liquid substrates, some examples for photocatalytic, solvent-free conversions are reported, such as the oxidation of benzyl alcohol to benzaldehyde [4] and the oxidation of benzenes to phenols [5]. Another field of

Tunable microwave-assisted method for the solvent-free and catalyst-free peracetylation of natural products

• Manuela Oliverio,
• Paola Costanzo,
• Monica Nardi,
• Carla Calandruccio,
• Raffaele Salerno and
• Antonio Procopio

Beilstein J. Org. Chem. 2016, 12, 2222–2233, doi:10.3762/bjoc.12.214

• , phenols and amino groups is a classical protection method in multistep syntheses as well as a transient chemical modification to improve the bioavailaibility and bioactivity of hydrophilic drugs and natural polyols [1][2][3][4][5][6][7][8][9]. Several in vitro and in vivo studies on peracetylated

• ]. Classically peracetylation reactions have been performed by treatment of alcohols and phenols with acid anhydrides or acid chlorides in the presence of bases [12]. Recently, the urgency to find more environmental benign methods for standard transformations, led to the optimization of methods employing

• applied to alcohols, phenols and polyols characterized by a huge chemical diversity and thermostability, simply tuning the MW settings. Such method is potentially universally applicable for green acetylation of hydrophilic biological molecules, thus improving their bioavailability and biological activity