Highly chemo-, enantio-, and diastereoselective [4 + 2] cycloaddition of 5H-thiazol-4-ones with N-itaconimides

• Shuai Qiu,
• Choon-Hong Tan and
• Zhiyong Jiang

Beilstein J. Org. Chem. 2016, 12, 2293–2297, doi:10.3762/bjoc.12.222

• class of sulfur-containing pro-nucleophiles in a highly enantio- and diastereoselective conjugate addition to nitroalkenes, providing α,α-disubstituted α-mercapto carboxylic acids [5]. Since then, several asymmetric variants using 5H-thiazol-4-ones as nucleophiles have been disclosed; such as amination

Robust C–C bonded porous networks with chemically designed functionalities for improved CO₂ capture from flue gas

• Damien Thirion,
• Joo S. Lee,
• Ercan Özdemir and
• Cafer T. Yavuz

Beilstein J. Org. Chem. 2016, 12, 2274–2279, doi:10.3762/bjoc.12.220

• Knoevenagel condensation of benzyl nitriles and aldehydes produces C–C bonded products with labile nitrile functionalities. In fact, nitrile groups have been shown in porous polymers (particularly in polymers of intrinsic microporosity (PIMs)) to be good precursors to several functionalities like carboxylic

• acids, tetrazoles, amines or amidoximes [14][15][16][17]. To the best of our knowledge the nitrile functionality has not been explored in other types of porous polymers, except our earlier work [18]. Herein we report the synthesis of two new cyanovinylene-bridged covalent organic polymers, indexed as

Elongated and substituted triazine-based tricarboxylic acid linkers for MOFs

• Arne Klinkebiel,
• Ole Beyer,
• Barbara Malawko and
• Ulrich Lüning

Beilstein J. Org. Chem. 2016, 12, 2267–2273, doi:10.3762/bjoc.12.219

• substituted) with two equivalents of an unsubstituted nitrile. Triple Suzuki coupling of the cores 3 with suitable phenyl- and biphenylboronic acid derivatives provided elongated tricarboxylic acid linkers as carboxylic acids 17 and 20 or their esters 16 and 19. Reduction of the nitro group and cleavage of

• the methoxy group gave the respective amino and hydroxy-substituted triazine linkers. Keywords: isoreticular; linker; MOF; Suzuki coupling; triazine; Introduction A typical building block for many metal–organic frameworks (MOFs) [1][2][3][4] carries two functional groups such as carboxylic acids or

• heterocycles resulting in a bridging ligand for the metal-containing „edges“ of the porous structures. Linkers with more than two ligating sites (carboxylic acids or heterocycles) have also been used successfully. Tri- to hexatopic linkers are also known. The prototype for a trivalent linker is 1,3,5

Superelectrophilic activation of 5-hydroxymethylfurfural and 2,5-diformylfuran: organic synthesis based on biomass-derived products

• Dmitry S. Ryabukhin,
• Dmitry N. Zakusilo,
• Mikhail O. Kompanets,
• Anton A.Tarakanov,
• Irina A. Boyarskaya,
• Tatiana O. Artamonova,
• Mikhail A. Khohodorkovskiy,
• Iosyp O. Opeida and
• Aleksander V. Vasilyev

Beilstein J. Org. Chem. 2016, 12, 2125–2135, doi:10.3762/bjoc.12.202

• molecules, such as alcohols, carboxylic acids, (hetero)aromatic ketones and aldehydes, phenols, etc. These biomass-derived platform chemicals are considered as an alternative and displacement to petroleum chemistry [17][18]. Among all these compounds, the preparation and reaction of 5-hydroxymethylfurfural

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

• bonds in the structure of α-aminocarbonyl compounds is also a well-known transition-metal-catalyzed process, which gives rise to the occurrence of formamides and carboxylic acids [26][29]. In this case the system O2/TEMPO is used as a catalyst for the cleavage process, but the reaction also proceeds

Potent triazine-based dehydrocondensing reagents substituted by an amido group

• Munetaka Kunishima,
• Daiki Kato,
• Nobu Kimura,
• Masanori Kitamura,
• Kohei Yamada and
• Kazuhito Hioki

Beilstein J. Org. Chem. 2016, 12, 1897–1903, doi:10.3762/bjoc.12.179

• reactions; amido substituents; dehydrocondensing reactions; Fischer-type esterification; triazines; Introduction We previously reported that dehydrocondensing reactions between carboxylic acids 1 and amines 2 to give amides 3 efficiently proceed in water or alcohols in the presence of the dehydrocondensing

• feature enables the use of DMT-MM for dehydrocondensing reactions in water or alcohols to give amides without the recovery of hydrolyzed carboxylic acids and the formation of corresponding esters. DMT-MM is quantitatively synthesized from 2-chloro-4,6-dimethoxy-1,3,5-triazine (CDMT) and N-methylmorpholine

• recognitions of carboxylic acids were affected by fuctionalized DMT-Am. However, once the reaction with 1 takes place, the functionalized tertiary amines 5 liberated, no longer affect the following reaction (Scheme 1d). As a consequence, the resulting acyloxyatriazine intermediate 4, which is the same

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

• for the use of carboxylic acids and pyromellitic dianhydride, respectively, as agents to cross-linking CDs. Other cross-linking agents such as epichlorohydrin, ethylene glycol diglycidyl ether, glutaraldehyde, benzoquinone or isocyanates can be also used [1][12]. The main objective of the study was to

• . As expected, the signals of the BTCA crosslinking agent can be clearly distinguished (labeled a, b, c and d). In particular, the carbon of the carboxylic groups appears at 172.2 ppm. This peak (a,d) corresponds to esterified and free carboxylic groups of BTCA present in free carboxylic acids and 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

• related to the application and preparation of unsaturated compounds, such as epoxides, aldehydes, ketones, carboxylic acids, and their derivatives [72][73][74][75][76][77][78][79][80][81][82][83][84][85][86][87][88][89][90][91][92][93][94][95][96][97][98][99][100][101][102][103][104][105][106][107][108

• ]. Since that time, this reaction has shown to be of general applicability and it has gained wide application for the oxidation of carbonyl compounds of different structures. In this reaction, cyclic ketones are transformed into lactones, acyclic ketones, into esters and aldehydes into carboxylic acids

• of peracids to oxidize cyclic and acyclic ketones and aldehydes to the corresponding lactones, esters, and carboxylic acids decreases in the series peroxotrifluoroacetic acid > monopermaleic acid > mono-o-perphthalic acid > 3,5-dinitroperbenzoic acid > p-nitroperbenzoic acid > MCPBA ≈ performic acid

Cp₂TiCl/D₂O/Mn, a formidable reagent for the deuteration of organic compounds

• Antonio Rosales and
• Ignacio Rodríguez-García

Beilstein J. Org. Chem. 2016, 12, 1585–1589, doi:10.3762/bjoc.12.154

• and unhindered radicals are normally reduced via hydrolysis of an organometallic alkyl-TiIV intermediate [37]. This HAT or protonation mechanism by Cp2TiCl/D2O/Mn, compared with the single-electron-transfer conditions using SmI2/D2O in the synthesis of α,α-dideuterated alcohols from carboxylic acids

Biosynthesis of oxygen and nitrogen-containing heterocycles in polyketides

• Franziska Hemmerling and
• Frank Hahn

Beilstein J. Org. Chem. 2016, 12, 1512–1550, doi:10.3762/bjoc.12.148

• their standard catalytic repertoire (Scheme 1). They transacylate the thioester of a PKS-bound polyketide onto a nucleophile. If the nucleophile is water, this leads to carboxylic acids. The reactions of backbone hydroxy groups or amines consequently give lactones and lactams. TE domains mostly form

Flow carbonylation of sterically hindered ortho-substituted iodoarenes

• Carl J. Mallia,
• Gary C. Walter and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2016, 12, 1503–1511, doi:10.3762/bjoc.12.147

• synthesis of ortho-substituted carboxylic acids, using carbon monoxide gas, has been studied for a number of substrates. The optimised conditions make use of a simple catalyst system compromising of triphenylphosphine as the ligand and palladium acetate as the pre-catalyst. Carbon monoxide was introduced

• of the reaction conditions was performed providing comparable yields to those obtained from the initial smaller test scale. This method could thus be an efficient and scalable approach to synthesising important intermediates containing ortho-substituted carboxylic acids. Experimental See Supporting

• carbonylation (left) and “tube-in-tube” reactor carbonylation (right). Schematic diagram of the flow process. The batch carbonylation of 2-chloro-1-iodobenzene in conventional lab (top) and using a Parr autoclave in high pressure lab (bottom). Structures of ortho-substituted carboxylic acids prepared via a

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

• intermediate reacted smoothly with benzyl bromide at room temperature to afford the monobenzylated PEG 2 in 77% yield (Table 1, entry 1). Afterwards, the alcohols 2 and 3a,b have to be oxidized to the corresponding carboxylic acids 6 and 7a,b. First of all, the direct oxidation reported in the literature in

• yields (Table 1, entries 5–7). Finally, the optimized two-step procedure enabled us to isolate the expected carboxylic acids 6 and 7a,b which are key intermediates in the synthesis of PEG-HMBPs. The carboxylic acids 6 and 7a,b reacted quantitatively with oxalyl chloride to give acyl chlorides 8 and 9a,b

• 13a,b were carried out with sodium hydroxide in methanol. The completion of the reactions was controlled by TLC. After neutralization with a cationic exchange Dowex® 50WX2 resin, the corresponding carboxylic acids 14a,b were isolated in quantitative yields. The HMBP moiety was subsequently

Multicomponent reactions: A simple and efficient route to heterocyclic phosphonates

• Mohammad Haji

Beilstein J. Org. Chem. 2016, 12, 1269–1301, doi:10.3762/bjoc.12.121

• biologically active scaffolds as well as some industrial compounds [1][2][3]. On the other hand, phosphonic acid and its related derivatives are considered as potential bioisosters of the corresponding carboxylic acids [4]. Thus, the incorporation of phosphonyl groups into the heterocyclic systems has led to

Synthesis of highly functionalized 2,2'-bipyridines by cyclocondensation of β-ketoenamides – scope and limitations

• Paul Hommes and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2016, 12, 1170–1177, doi:10.3762/bjoc.12.112

• carboxylic acids [33][34][35][36][37][38][39][40]. These components form α-alkoxy-substituted β-ketoenamides as precursors of highly substituted pyridine derivatives. We therefore tried to independently prepare β-ketoenamides with this substitution pattern starting from simple 1,3-diketones such as 1a. An

Efficient syntheses of climate relevant isoprene nitrates and (1R,5S)-(−)-myrtenol nitrate

• Sean P. Bew,
• Glyn D. Hiatt-Gipson,
• Graham P. Mills and
• Claire E. Reeves

Beilstein J. Org. Chem. 2016, 12, 1081–1095, doi:10.3762/bjoc.12.103

• , α-farnesene, β-gurjunene, β-muurolene and allo-aromadendrene, as well as simple alkanes, alkenes, alcohols, esters, aldehydes, ketones and carboxylic acids [3]. The quantities of BVOCs released far exceed non-methane hydrocarbon emissions derived from anthropogenic activity (~90 Tg C yr−1 where 1 Tg

1H-Imidazol-4(5H)-ones and thiazol-4(5H)-ones as emerging pronucleophiles in asymmetric catalysis

• Antonia Mielgo and
• Claudio Palomo

Beilstein J. Org. Chem. 2016, 12, 918–936, doi:10.3762/bjoc.12.90

• be easily hydrolyzed to provide carboxylic acids or their derivatives carrying different functionalities. The most common pronucleophiles of this type are oxazol-5-(4H)-ones or azlactones (Figure 1a, X = O), which have been thoroughly investigated and reviewed [23][24][25]. On the other hand, since

• efficient platforms for bidentate coordination in metal catalysis and good precursors of carboxylic acids, ketones and aldehydes upon oxidative cleavage of the keto/diol moiety [72]. More recently, a comprehensive study on the first evidence of the utility of these acceptors in organocatalysis has been

• ), particularly into hydantoins 37–43 after hydrolysis of the corresponding adducts 30–32 [55]. Oxidative elaboration of the ketol unit in these compounds provides the corresponding carboxylic acids 40/41, the aldehyde 42 and the ketone 43. Therefore this methodology facilitates a novel entry to functionalized

From steroids to aqueous supramolecular chemistry: an autobiographical career review

• Bruce C. Gibb

Beilstein J. Org. Chem. 2016, 12, 684–701, doi:10.3762/bjoc.12.69

• “coated” with water-solubilizing carboxylic acids/carboxylates to bestow good water solubility under basic conditions, and; 2) possessed a rim of hydrophobicity around the entrance to its interior hydrophobic pocket. We envisioned that driven by the hydrophobic effect this host would readily form 1:1

(Thio)urea-mediated synthesis of functionalized six-membered rings with multiple chiral centers

• Giorgos Koutoulogenis,
• Nikolaos Kaplaneris and
• Christoforos G. Kokotos

Beilstein J. Org. Chem. 2016, 12, 462–495, doi:10.3762/bjoc.12.48

• bonds, such as carboxylic acids, tetrazoles, thioureas, etc. The selectivity observed, when steric shielding interaction is employed, is due to the bulky group of the catalyst. This group shields one face of the enamine to provide the selectivity. The third most valuable and studied mode of activation

Recent advances in N-heterocyclic carbene (NHC)-catalysed benzoin reactions

• Rajeev S. Menon,
• Akkattu T. Biju and
• Vijay Nair

Beilstein J. Org. Chem. 2016, 12, 444–461, doi:10.3762/bjoc.12.47

• corresponding carboxylic acids could compete with homo-benzoin reactions, but can be limited by careful exclusion of oxygen from the reaction mixture. A few recent reports of homo-benzoin reactions are discussed in the following passages. Stetter’s report in 1976 of thiazolium salt-catalysed benzoin reactions

Cascade alkylarylation of substituted N-allylbenzamides for the construction of dihydroisoquinolin-1(2H)-ones and isoquinoline-1,3(2H,4H)-diones

• Ping Qian,
• Bingnan Du,
• Wei Jiao,
• Haibo Mei,
• Jianlin Han and
• Yi Pan

Beilstein J. Org. Chem. 2016, 12, 301–308, doi:10.3762/bjoc.12.32

• [18][19], decarboxylative alkenylation of cycloalkanes with aryl vinylic carboxylic acids [20][21], trifluoromethylthiolation [22], thiolation [23][24], alkenylation [25][26], dehydrogenation−olefination and esterification [27][28], radical addition/1,2-aryl migration [29], cascade alkylation

Base metal-catalyzed benzylic oxidation of (aryl)(heteroaryl)methanes with molecular oxygen

• Hans Sterckx,
• Johan De Houwer,
• Carl Mensch,
• Wouter Herrebout,
• Kourosch Abbaspour Tehrani and
• Bert U. W. Maes

Beilstein J. Org. Chem. 2016, 12, 144–153, doi:10.3762/bjoc.12.16

• ; catalyzed; molecular oxygen; oxygenation; Introduction Direct oxidation of C(sp3)–H bonds is a useful and fast method to convert fairly unreactive substrates to useful functional groups for organic synthesis like alcohols, ketones, aldehydes and carboxylic acids. Classical oxidation protocols rely on the

Diastereoselective Ugi reaction of chiral 1,3-aminoalcohols derived from an organocatalytic Mannich reaction

• Samantha Caputo,
• Andrea Basso,
• Lisa Moni,
• Renata Riva,
• Valeria Rocca and
• Luca Banfi

Beilstein J. Org. Chem. 2016, 12, 139–143, doi:10.3762/bjoc.12.15

• simpler variants) [10][11][12]. On the other hand, diastereoselective reactions using at least one chiral component are troublesome. Chiral isocyanides and chiral carboxylic acids invariably afford nearly 1:1 mixtures. α-Chiral aldehydes have a high tendency to racemize/epimerize [13][14] and additionally

Copper-catalyzed intermolecular oxyamination of olefins using carboxylic acids and O-benzoylhydroxylamines

• Brett N. Hemric and
• Qiu Wang

Beilstein J. Org. Chem. 2016, 12, 22–28, doi:10.3762/bjoc.12.4

• -benzoylhydroxylamines as an electrophilic amine source and carboxylic acids as a nucleophilic oxygen source to achieve a modular difunctionalization of olefins. The reaction proceeded in a regioselective manner with moderate to good yields, exhibiting a broad scope of carboxylic acid, amine, and olefin substrates

• oxygen sources, such as TEMPO and acetate. Herein, we envisioned that a copper-catalyzed intermolecular olefin oxyamination could be achieved using O-acylhydroxylamines as an electrophilic amino precursor [35][36][37][38][39] and carboxylic acids as a nucleophilic oxygen source (Scheme 1E). The proposed

• and 2a, providing 4a in a clean 78% isolation yield (Table 1, entry 13) [43]. With established oxyamination conditions in hand, the scope of carboxylic acids in this transformation was examined using olefin 2a and O-benzoylhydroxylamine 3a (Scheme 2). Both aryl and alkyl carboxylic acid derivatives

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

• aromatic and aliphatic carboxylic acids, including ibuprofen. The Mycobacterium CAR catalyzed carboxylic acid reduction to give aldehydes, followed by a Wittig reaction to afford the products α,β-unsaturated esters with extension of two carbon atoms, demonstrating a new chemo-enzymatic method for the

• acids are abundant from natural resources, aromatic carboxylic acids could be prepared by the degradation of lignin, an unused and abundant component of biomass, although the effective methods for the degradation of lignin need to be developed. These carboxylic acids could be reduced to their

• require strong reducing reagents such as metal hydrides, posting operational danger and low selectivity. In addition, the conversion of COOH into CHO requires particular hydride reagents, to avoid the further reduction to primary alcohols [26]. On the contrary, enzymatic reduction of carboxylic acids

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

• Sciences, Beijing, 100190, P. R. China 10.3762/bjoc.11.233 Abstract A copper-catalyzed oxidative direct formation of amides from nonactivated carboxylic acids and azoles with dioxygen as an activating reagent is reported. The azole amides were produced in good to excellent yields with a broad substrate

• ][13][14][15][16][17][18][19][20][21], the acylation of amines with free carboxylic acids is still the most common method employed due to the availability of the starting materials and its relatively clean process feature, whereby water is the only byproduct in the transformation [22]. However

• , preactivation of the free carboxylic acids is always required, and stoichiometric activating reagents or coupling reagents are mandatory in the classic methods of amide formation (Scheme 1a) [23]. In some cases, corrosive byproducts (HCl) are unavoidable and the activating reagent is difficult to remove from