Strategies toward protecting group-free glycosylation through selective activation of the anomeric center

• A. Michael Downey and
• Michal Hocek

Beilstein J. Org. Chem. 2017, 13, 1239–1279, doi:10.3762/bjoc.13.123

α-Acetoxyarone synthesis via iodine-catalyzed and tert-butyl hydroperoxide-mediateded self-intermolecular oxidative coupling of aryl ketones

• Liquan Tan,
• Cui Chen and
• Weibing Liu

Beilstein J. Org. Chem. 2017, 13, 1079–1084, doi:10.3762/bjoc.13.107

• also observed that 2a was obtained in almost quantitative yields when 1a was reacted with tert-butylperoxybenzoate (TBPB) or benzoic acid under the standard conditions (Scheme 3, reactions 5 and 6). These results suggest that 2-iodo-1-phenyl ketone, TBPB, and benzoic acid are generated in situ from 1a

Interactions between shape-persistent macromolecules as probed by AFM

• Johanna Blass,
• Jessica Brunke,
• Franziska Emmerich,
• Cédric Przybylski,
• Vasil M. Garamus,
• Artem Feoktystov,
• Roland Bennewitz,
• Gerhard Wenz and
• Marcel Albrecht

Beilstein J. Org. Chem. 2017, 13, 938–951, doi:10.3762/bjoc.13.95

• 4 was prepared by Sonogashira reaction of 3 with trimethylsilylacetylene. Subsequent deprotection of the TMS groups using tetra-n-butylammonium fluoride and saponification of the tert-butyl ester with trifluoroacetic acid resulted in the corresponding benzoic acid 6. The latter was coupled to 6

• corresponding to one additional repeating unit. Among each discrete envelope, one to three supplementary ions, have been detected with a constant 165.2 mass unit shift, revealing the presence of small quantities of the repeat unit originating from unmodified benzoic acid derivative 6, e.g., at 2,621.33 and

Fluorinated cyclohexanes: Synthesis of amine building blocks of the all-cis 2,3,5,6-tetrafluorocyclohexylamine motif

• Tetiana Bykova,
• Nawaf Al-Maharik,
• Alexandra M. Z. Slawin and
• David O'Hagan

Beilstein J. Org. Chem. 2017, 13, 728–733, doi:10.3762/bjoc.13.72

• reduction on benzoic acid, quenching with methyl iodide, and then subsequent conversion of the cyclohexadiene product to a tetrafluorocycloheane motif [11]. The methyl group was a design feature to block hydrogen fluoride elimination from the position alpha to the aldehyde. The diastereoisomers of all cis

Synthesis of new pyrrolidine-based organocatalysts and study of their use in the asymmetric Michael addition of aldehydes to nitroolefins

• Alejandro Castán,
• Ramón Badorrey,
• José A. Gálvez and
• María D. Díaz-de-Villegas

Beilstein J. Org. Chem. 2017, 13, 612–619, doi:10.3762/bjoc.13.59

• possibility of accelerating the formation of the enamine intermediate and simultaneously activating the nitroalkene by using a combination of organocatalyst OC4, a Brønsted acid and an achiral thiourea. Thus the reaction was repeated in the presence of a combination of benzoic acid and N,N'-diphenylthiourea

• (TU1) as additives. The enantioselectivity of both syn and anti-adducts reached quite good values (87% ee and 91% ee, respectively) but the diastereoselectivity dropped to 67:33. The aryl group of benzoic acid was varied (Table 5) in an effort to improve the diastereoselectivity. The best results in

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

• they used a stoichiometric amount of reactive iron complex [Fe(II)(BPMEN)(CH3CN)2](ClO4)2 to achieve ortho-hydroxylation of benzoic acid in the presence of H2O2, affording salicylic acid in low yields [52]. In the past decade, the selectivity and yield of C–H hydroxylation of arenes were highly

• facilitate C–H hydroxylation of benzoic acids and heteroarenes [55]. An amidation reaction between benzoic acid and 2-(pyridine-2-yl)isopropylamine gave N-(2-(pyridine-2-yl)isopropyl)benzamides, which could be hydroxylated at the ortho position in moderate to excellent yields. The reaction was promoted by a

• investigation revealed that HFIP participated in the catalytic cycle before the activation of C–H bond. 1.2.2.2 Carboxylic acid, ketone and their derivatives as directing groups: In 2009, the Yu group used Pd(OAc)2 and accomplished the direct ortho-hydroxylation of benzoic acid [69]. Their developed protocol

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

• hydrogenolysis of the resulting double bond with Pd(OH)2/C, gave benzoic acid 213. Next, the latter was converted to α-diazo-β-keto ester 214 which then was submitted to the rhodium(II) acetate catalyzed intramolecular, carbon–hydrogen insertion reaction to give the spiroindane 215. Finally, the spiroindane 215

A chemoselective and continuous synthesis of m-sulfamoylbenzamide analogues

• Arno Verlee,
• Thomas Heugebaert,
• Tom van der Meer,
• Pavel I. Kerchev,
• Frank Van Breusegem and
• Christian V. Stevens

Beilstein J. Org. Chem. 2017, 13, 303–312, doi:10.3762/bjoc.13.33

• )benzoic acid [15][16][17]. This synthetic approach is a two-step procedure and therefore needs two subsequent work-up steps, limiting the yield and resulting in a more time-consuming synthetic approach. Yang et al. [18] reported a one-pot synthetic strategy for m-sulfamoylbenzamide analogues starting from

Versatile synthesis of end-reactive polyrotaxanes applicable to fabrication of supramolecular biomaterials

• Atsushi Tamura,
• Asato Tonegawa,
• Yoshinori Arisaka and
• Nobuhiko Yui

Beilstein J. Org. Chem. 2016, 12, 2883–2892, doi:10.3762/bjoc.12.287

• polymer (elution volume: 3.7 mL) or α-CD (elution volume: 4.5 mL) in the SEC chart. Figure 1 shows the SEC chart of the crude products of the PEG-NH2/α-CD pseudopolyrotaxane treated with 4-(azidomethyl)benzoic acid (2a) in the presence of 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride

• obtained from NOF Corporation (Tokyo, Japan). α-Cyclodextrin (α-CD) was obtained from Ensuiko Sugar Refining (Tokyo, Japan). 4-(Azidomethyl)benzoic acid was synthesized according to the previous report [27]. 4-Azidobenzoic acid, 4-methylbenzoic acid, p-(tert-butyl)phenylacetylene, and 2-(2-hydroxyethoxy

• temperature. After the reaction, the precipitate was collected by centrifugation and freeze-dried for 1 day to obtain a pseudopolyrotaxane as powder (yield 1.37 g). Then, 4-(azidomethyl)benzoic acid (106 mg, 597 μmol), DMT-MM (165 mg, 597 μmol), and the pseudopolyrotaxane were allowed to react in methanol (14

Synthesis of polyhydroxylated decalins via two consecutive one-pot reactions: 1,4-addition/aldol reaction followed by RCM/syn-dihydroxylation

• Michał Malik and
• Sławomir Jarosz

Beilstein J. Org. Chem. 2016, 12, 2602–2608, doi:10.3762/bjoc.12.255

• allylic alcohols as substrates in Mitsunobu reactions can be a challenging task, some successful examples can be found in the literature [49][50]. However, the reaction with benzoic acid did not proceed at all, whereas application of p-nitrobenzoic acid yielded a complicated mixture of products. Therefore

Catalytic Wittig and aza-Wittig reactions

• Zhiqi Lao and
• Patrick H. Toy

Beilstein J. Org. Chem. 2016, 12, 2577–2587, doi:10.3762/bjoc.12.253

• as the reducing reagent to regenerate 33. Most recently they refined such reactions using 22 as the pre-catalyst, trimethoxysilane as the reducing reagent, and catalytic benzoic acid to facilitate phosphine oxide reduction [27]. At about the same time as the penultimate report by Werner and co

Synthesis and NMR studies of malonyl-linked glycoconjugates of N-(2-aminoethyl)glycine. Building blocks for the construction of combinatorial glycopeptide libraries

• Markus Nörrlinger,
• Sven Hafner and
• Thomas Ziegler

Beilstein J. Org. Chem. 2016, 12, 1939–1948, doi:10.3762/bjoc.12.183

• (ΔG‡r) using the Eyring model. The found ΔG‡r values (17.9–18.3 kcal/mol) were in good accordance with those of other known PNA-derivates (17.9–19 kcal/mol). The PNA-based glycoprotein building blocks described here will be used in combination with previously described benzoic acid-based glycopeptoids

Unusual reactions of diazocarbonyl compounds with α,β-unsaturated δ-amino esters: Rh(II)-catalyzed Wolff rearrangement and oxidative cleavage of N–H-insertion products

• Valerij A. Nikolaev,
• Jury J. Medvedev,
• Olesia S. Galkina,
• Ksenia V. Azarova and
• Christoph Schneider

Beilstein J. Org. Chem. 2016, 12, 1904–1910, doi:10.3762/bjoc.12.180

• the two basic reaction products, benzoic acid was isolated as well (43%; Table 2, entry 9). By this means during the course of Rh(II)-catalyzed reactions of aroyldiazomethanes 2a–c, diazoketoesters 3a,b and diazodiketone 3c with aminoester 1, contrary to the similar reactions of diazoesters [15], two

• hydroperoxide G, which then converts into 1,2-dioxetane H [30]. Subsequent cleavage of σ-С–С and О–О bonds in the structure of dioxetane H gives rise to the formation of amides 4 or 7 and the appropriate рara-substituted benzoic acid, which was isolated in several cases from reaction mixtures. A leading role in

Rearrangements of organic peroxides and related processes

• Ivan A. Yaremenko,
• Vera A. Vil’,
• Dmitry V. Demchuk and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2016, 12, 1647–1748, doi:10.3762/bjoc.12.162

• triethylamine. The obtained product 4-hydroxycyclohexen-2-one 273 releases benzoic acid through β-elimination under the basic conditions to give cyclohexadienone 274 (Scheme 83) [357]. The base-catalyzed isomerization of bicyclic saturated fulvene endoperoxides 275 is employed as one approach to the preparation

Towards potential nanoparticle contrast agents: Synthesis of new functionalized PEG bisphosphonates

• Souad Kachbi-Khelfallah,
• Maelle Monteil,
• Margery Cortes-Clerget,
• Evelyne Migianu-Griffoni,
• Jean-Luc Pirat,
• Olivier Gager,
• Julia Deschamp and
• Marc Lecouvey

Beilstein J. Org. Chem. 2016, 12, 1366–1371, doi:10.3762/bjoc.12.130

• PEG chain cleavage and the recovery of benzoic acid from alcohol 2. Besides, the mixture IBX/oxone gave the expected product inseparable of IBX byproducts. Only oxidation using TEMPO and BAIB furnished the pure corresponding carboxylic acid. Nevertheless, the low obtained yields encouraged us to test

Unconventional application of the Mitsunobu reaction: Selective flavonolignan dehydration yielding hydnocarpins

• Guozheng Huang,
• Simon Schramm,
• Jörg Heilmann,
• David Biedermann,
• Vladimír Křen and
• Michael Decker

Beilstein J. Org. Chem. 2016, 12, 662–669, doi:10.3762/bjoc.12.66

• reaction. We investigated the reaction under Mitsunobu conditions using the latter sequence of addition [10] for silibinin and benzoic acid, or 2,2-dimethyl-3-(nitrooxy)propanoic acid (7, Scheme 1), an NO-donor compound with several biological properties, e.g., vasorelaxation [27]. Compound 7 had initially

• 1 and 5). In absence of an acid, 2,3-dehydration did not occur even using excessive amounts of Ph3P and DIAD (Table 1, entries 7 and 8). In the absence of DIAD, silibinin was not converted into any other compound (Table 1, entry 9). Benzoic acid had been applied to synthesize 23-O-benzoylsilibinin

• (8b) in 55% yield [9]. Using benzoic acid with 6 equiv of Ph3P and 4 equiv of DIAD, silibinin was converted into ester 9b with a yield of 33% after purification (Table 1, entry 4). Again hydrolysis of 9b yielded hydnocarpin D (2). Being encouraged by the feasibility of using a common acid but still

Enantioselective additions of copper acetylides to cyclic iminium and oxocarbenium ions

• Jixin Liu,
• Srimoyee Dasgupta and
• Mary P. Watson

Beilstein J. Org. Chem. 2015, 11, 2696–2706, doi:10.3762/bjoc.11.290

• iminium ion 31 (Scheme 10) [32]. Subsequent alkynylation was accomplished using a CuI/N-Pinap catalyst to give N-benzylisoquinolines in exceptional yields and enantioselectivities. Notably, catalytic benzoic acid is necessary to achieve high yields. The authors hypothesize that this acid additive

Recent highlights in biosynthesis research using stable isotopes

• Jan Rinkel and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2015, 11, 2493–2508, doi:10.3762/bjoc.11.271

• agreement with the detection of (ring-2H5)benzoic acid in culture extracts from labeling experiments with (ring-2H5)Phe. This interconversion of two proteinogenic amino acids in the biosynthesis of an NRPS compound from secondary metabolism is unprecedented and its discovery was strongly supported by the

Synthesis of α,β-unsaturated esters via a chemo-enzymatic chain elongation approach by combining carboxylic acid reduction and Wittig reaction

• Yitao Duan,
• Peiyuan Yao,
• Yuncheng Du,
• Jinhui Feng,
• Qiaqing Wu and
• Dunming Zhu

Beilstein J. Org. Chem. 2015, 11, 2245–2251, doi:10.3762/bjoc.11.243

• toward benzoic acid (2a) (Supporting Information File 1, Table S1) were 1.75 ± 0.16 mM and 0.93 mM−1·s−1, respectively. They were lower than those for NiCAR [31], SrCAR [28] and MnCAR [33]. In order to explore the application potential of Mycobacterium CAR, its substrate specificity was examined with the

Recent advances in copper-catalyzed C–H bond amidation

• Jie-Ping Wan and
• Yanfeng Jing

Beilstein J. Org. Chem. 2015, 11, 2209–2222, doi:10.3762/bjoc.11.240

• functionalization with nitrogen nucleophiles, including amides, sulfonamides and primary arylamines. In addition, the oxazole-based DG could be easily deprotected to provide the corresponding benzoic acid 44 by heating in EtOH in the presence of KOH (Scheme 13). As another easily available N-containing aromatic

Molecular-oxygen-promoted Cu-catalyzed oxidative direct amidation of nonactivated carboxylic acids with azoles

• Wen Ding,
• Shaoyu Mai and
• Qiuling Song

Beilstein J. Org. Chem. 2015, 11, 2158–2165, doi:10.3762/bjoc.11.233

• ), inexpensive and readily available pyridine was employed as both the ligand and base in our case. Results and Discussion Our initial exploration commenced with benzoic acid (1) and benzimidazole (2) as the model substrates to investigate the copper-catalyzed oxidative direct amidation reaction (Table 1). The

• ) were mixed with benzoic acid under the standard conditions, compound 29 was obtained in 45% yield instead of the predicted amide 3 (Scheme 3a). Compound 3 was not detected in the reaction. Similarly, when 2-naphthoic acid (30) was used instead of benzoic acid (1), compound 31 was afforded in 56% yield

• reason to believe that the above proposed mechanism is plausible. In addition, pyridine N-oxide was applied to the benzoic acid standard conditions in the presence/absence of dioxygen. However, only a trace amount of the desired product 3 was ever detected, thus it was ruled out as a possible pathway

The facile construction of the phthalazin-1(2H)-one scaffold via copper-mediated C–H(sp²)/C–H(sp) coupling under mild conditions

• Wei Zhu,
• Bao Wang,
• Shengbin Zhou and
• Hong Liu

Beilstein J. Org. Chem. 2015, 11, 1624–1631, doi:10.3762/bjoc.11.177

• on the use of prefunctionalized benzoic acid, such as phthalic anhydride or 2-formylbenzoic acid, as starting materials and suffer from low yields, poor regioselectivity and scope limitations [11][12]. Therefore, there is still a need for synthetic chemists to develop efficient and expedient routes

Preparative semiconductor photoredox catalysis: An emerging theme in organic synthesis

• David W. Manley and
• John C. Walton

Beilstein J. Org. Chem. 2015, 11, 1570–1582, doi:10.3762/bjoc.11.173

• further oxidation. SCPC oxidations that take place with varying success include toluene to benzaldehyde and benzoic acid [25], cyclohexane to cylohexanone [26], benzylic and allylic alcohols to carbonyl compounds [27] and alkene epoxidations [28]. Conventional syntheses of coumarins, which are important

Gold-catalyzed formation of pyrrolo- and indolo-oxazin-1-one derivatives: The key structure of some marine natural products

• Sultan Taskaya,
• Nurettin Menges and
• Metin Balci

Beilstein J. Org. Chem. 2015, 11, 897–905, doi:10.3762/bjoc.11.101

• acids has been reported in the literature to give the corresponding lactones [33][34][35][36][37][38][39][40]. For example, gold(I)-catalyzed reaction of 2-(phenylethynyl)benzoic acid (8) yielded the exo- and endo-dig cyclization products, lactones 9 and 10 in 62% yield in a ratio of 6:1 (Scheme 1) [41

Cross-dehydrogenative coupling for the intermolecular C–O bond formation

• Igor B. Krylov,
• Vera A. Vil’ and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2015, 11, 92–146, doi:10.3762/bjoc.11.13

• ]. The 2-aminopyridine-1-oxide directing group was used in a rare example of a cobalt-catalyzed oxidative alkoxylation of arenes 66 and alkenes 67 to afford products 68 and 69 under mild contitions [69] (Scheme 14). The directing group can be removed to obtain the corresponding benzoic acid 71 from the