Recent applications of chiral calixarenes in asymmetric catalysis

• Mustafa Durmaz,
• Erkan Halay and
• Selahattin Bozkurt

Beilstein J. Org. Chem. 2018, 14, 1389–1412, doi:10.3762/bjoc.14.117

• ). The corresponding tetrahydropyridine derivatives 124 were obtained in good to excellent yields but the enantioselectivity remained moderate. Calixarene phosphonic acid (cR,pR)-121 was also tested in the asymmetric ring opening of several cyclic meso epoxides 125 with benzoic acid (Scheme 41). Good

• )-121. Asymmetric ring opening of epoxides catalyzed by (cR,pR)-121.

A stereoselective and flexible synthesis to access both enantiomers of N-acetylgalactosamine and peracetylated N-acetylidosamine

• Bettina Riedl and
• Walther Schmid

Beilstein J. Org. Chem. 2018, 14, 856–860, doi:10.3762/bjoc.14.71

• -diethyl tartrate (L-DET) directing the reaction towards the D-galacto-configured epoxythreitol 5a. Alternatively, epoxidation of 4b with D-DET was used to access L-galacto-configured epoxythreitol 5b. A procedure by Miyashita et al. [19] for nucleophilic substitution of epoxides by an azide functionality

One-pot sequential synthesis of tetrasubstituted thiophenes via sulfur ylide-like intermediates

• Jun Ki Kim,
• Hwan Jung Lim,
• Kyung Chae Jeong and
• Seong Jun Park

Beilstein J. Org. Chem. 2018, 14, 243–252, doi:10.3762/bjoc.14.16

• center and the substituents on the sulfur atom [10]. In general, these reagents are often applied in the preparation of simple small rings [13], such as epoxides [14][15][16][17][18], cyclopropanes [19][20][21][22], aziridines [23], indoles [24], pyrroles [24], and indolines [25]. In addition, other

One-pot three-component route for the synthesis of S-trifluoromethyl dithiocarbamates using Togni’s reagent

• Azim Ziyaei Halimehjani,
• Martin Dračínský and
• Petr Beier

Beilstein J. Org. Chem. 2017, 13, 2502–2508, doi:10.3762/bjoc.13.247

• dithiocarbamates via a one-pot reaction of an amine, CS2 and an electrophile is of great interest due to its simplicity and environmental friendly procedure. Diverse electrophiles including alkyl halides [18], epoxides [19], alkenes [20][21][22], aldehydes [23], and alcohols [24] were applied for the synthesis of

Synthesis of ergostane-type brassinosteroids with modifications in ring A

• Vladimir N. Zhabinskii,
• Darya A. Osiyuk,
• Yuri V. Ermolovich,
• Natalia M. Chaschina,
• Tatsiana S. Dalidovich,
• Miroslav Strnad and
• Vladimir A. Khripach

Beilstein J. Org. Chem. 2017, 13, 2326–2331, doi:10.3762/bjoc.13.229

• mesylation of diol 18 produced dimesylate 19, which was treated with zinc dust and sodium iodide in refluxing DMF (Tipson–Cohen reaction [16]) to give, after deacetylation, B-lactone olefin 21 in 96% yield. 2α,3α- and 2β,3β-epoxides of type 4 and 5 Olefins of type 3 are evident intermediates for the

• isomeric 2,3-epoxides 22 and 24 with a 7-membered B-ring lactone was accomplished starting from the olefin 21 (Scheme 4). The reaction of peracids with Δ2-steroids possessing a six-membered B ring is known to proceed from the less hindered side of the molecule and results in the formation of 2α,3α-epoxides

• transformed, on treatment with KOH, into the epoxide 24. The structures of isomeric epoxides 22 and 24 were confirmed by their NOESY spectra as shown in Scheme 4. The obvious NOE correlation between H-3 and H-5 in 24 suggested the spatial vicinity of these two protons, thus the epoxide ring was β-oriented. On

Solvent-free and room temperature synthesis of 3-arylquinolines from different anilines and styrene oxide in the presence of Al₂O₃/MeSO₃H

• Hashem Sharghi,
• Mahdi Aberi,
• Mohsen Khataminejad and
• Pezhman Shiri

Beilstein J. Org. Chem. 2017, 13, 1977–1981, doi:10.3762/bjoc.13.193

• with styrene oxide to form the desired products (Table 2). In continuation of our study, aliphatic epoxides were also checked; unfortunately, they were not applicable for the preparation of quinolines. All novel and known compounds were characterized by their melting points, IR, 1H NMR, 13C NMR and

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

Exploring endoperoxides as a new entry for the synthesis of branched azasugars

• Svenja Domeyer,
• Mark Bjerregaard,
• Henrik Johansson and
• Daniel Sejer Pedersen

Beilstein J. Org. Chem. 2017, 13, 644–647, doi:10.3762/bjoc.13.63

• these building blocks provided access to a variety of derivatives including tetrahydrofurans, epoxides and protected amino-tetraols. Keywords: azasugar; carbohydrate; cycloaddition; endoperoxide; photochemistry; Introduction Azasugars are small organic compounds that can mimic carbohydrates or their

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

• have demonstrated that the synthesis of 1a could be achieved using the 2-substituted chroman derivatives (R)-1-((R)-6-fluorochroman-2-yl)ethane-1,2-diol (2) and (R)-1-((S)-6-fluorochroman-2-yl)ethane-1,2-diol (3) or the corresponding chroman epoxides 4 and 5 as late-stage intermediates. Although the

• consensus synthetic strategy for 1a involves the convergent assembly of chroman-based key subunits, the question of how best to access them remains open. The intramolecular ring-opening of enantiomerically pure epoxides by the phenolic hydroxy group is one of the most popular methods to construct 3 (Scheme

• . However, it has been reviewed that not only benzylic epoxides but also non-benzylic epoxides are sensitive to the standard hydrogenation/debenzylation conditions [35]. Whereas benzylic epoxides are highly sensitive to hydrogenation conditions, non-benzylic epoxides, depending on the reaction conditions

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

• rhodium(II) complex 220 followed by the carboxylic methyl ester hydrolysis/decarboxylation in DMSO/H2O at 120 °C with up to 72% enantiomeric excess (Scheme 60) [89]. 1.7 From epoxides and cyclopropanes The chalcone epoxides 221 ring opening catalyzed by indium(III) chloride, followed by a intramolecular

• Friedel–Crafts alkylation has been used by Ahmed et al. for the synthesis of 2-hydroxyindan-1-one derivatives 222 in good yields (Scheme 61) [90]. The same research group used the THP (tetrahydropyranyl) and MOM (methoxymethyl) protected chalcone epoxides and tin(IV) chloride under mild conditions to

Solid-phase enrichment and analysis of electrophilic natural products

• Frank Wesche,
• Yue He and
• Helge B. Bode

Beilstein J. Org. Chem. 2017, 13, 405–409, doi:10.3762/bjoc.13.43

• extracts via their reactivity against azide as a nucleophile followed by their subsequent enrichment using a cleavable azide-reactive resin (CARR). Using this approach, natural products carrying epoxides and α,β-unsaturated enones as well as several unknown compounds were identified in crude extracts from

• entomopathogenic Photorhabdus bacteria. Keywords: azides; click chemistry; enrichment; electrophilic natural products; epoxides; glidobactin; Photorhabdus; stilbenes; Introduction Microorganisms are a major source for novel natural products and the subsequent development of new drugs for all kinds of

• dehydroalanine [6][7], ketones, aldehydes [8][9], carboxylic acids [8][9], amines [8][9][10], thiols [8][9], alcohols [11], epoxides [12], terminal alkynes [13][14] and azides [15] can be targeted to introduce a label. Such labels might increase the visibility in UV or MS detection in liquid chromatography

New approaches to organocatalysis based on C–H and C–X bonding for electrophilic substrate activation

• Pavel Nagorny and
• Zhankui Sun

Beilstein J. Org. Chem. 2016, 12, 2834–2848, doi:10.3762/bjoc.12.283

• activation is accomplished through a C–H hydrogen bond with cyclic ester carbonyls. The following study by the Bibal group described the use of catalysts L11 as hydrogen bond donors for the activation of epoxides toward ring-opening aminolysis with amines (Scheme 6) [54]. Significant rate enhancement was

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

• using 1,1,1,3,3,3-hexafluoroisopropanol (HFIP) as reaction medium as well as the reaction promoter. The first choice of HFIP was based on its recently found ability to promote high-yielding IFCEA cyclization of benzylic epoxides [29]. Unfortunately, however, refluxing a solution of (±)-6a in HFIP for 4

• epoxides are compatible under IFCEA cyclization (as demonstarted previously by us [22][23] and others [29][33]), this methodology should also be applicable with the enantioenriched substrates. Further work is in progress aimed at synthesizing such type of fused hybrid molecules with different ring sizes

Sydnone C-4 heteroarylation with an indolizine ring via Chichibabin indolizine synthesis

• Florin Albota,
• Mino R. Caira,
• Constantin Draghici,
• Florea Dumitrascu and
• Denisa E. Dumitrescu

Beilstein J. Org. Chem. 2016, 12, 2503–2510, doi:10.3762/bjoc.12.245

• transformation of N-heteroaromatic salts into the corresponding N-ylides with epoxides was reported recently [5][17][18]. The next step represents a 1,3-dipolar cycloaddition of the bis(1,3-dipoles) 10 with formation of dihydro-indolizines 11 which, under the reaction conditions, are dehydrogenated to the final

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

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

• (Scheme 1). This SET is capable of promoting and/or catalyzing several transformations in organic chemistry [17][18][19][20][21][22][23][24][25]. One of the most relevant transformations is the H/D-atom transfer from H2O/D2O to carbon radicals (pathway A) (obtained from epoxides [26][27][28], ozonides [29

• epoxides [2][27][37], ozonides [29], ketones [31][32], activated halides [30][31][32], alkenes and alkynes [33]. Several examples are presented in Scheme 3. The results show that the combination Cp2TiCl/D2O/Mn is able to promote and/or catalyze deuteration of organic compounds by reduction or radical

• summary, we presented an overview of the Cp2TiCl/D2O/Mn combination as an efficient, cheap, selective, and sustainable reagent compatible with different functional groups that mediates the deuteration of organic compounds from epoxides, ozonides, carbonyl compounds, activated halides, alkenes and alkynes

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

• are biosynthesised in seven principal ways (Scheme 2). Those comprise nucleophilic addition of a hydroxy group to electrophiles like epoxides 4, carbonyl groups 6 or Michael acceptors 9, potentially followed by further processing (a–c in Scheme 2). Lactones 12 are formed by transacylation of a

• building block [34][35][36]. 1.1.3 Epoxide opening: The nucleophilic opening of epoxides is probably the most abundant type of reaction leading to furans and pyrans. It, for example, plays an important role in the biosynthesis of ionophoric terrestrial and marine polyethers (see chapter 1.3). In this

• experiments. The process starts by oxidoreductase domain MmpE-catalysed epoxidation of the double bond between C10 and C11. Olefin 53 is thus a branching point from which two series of analogous C10–C11 epoxides (53–61) and C10–C11 (not shown) olefins arise (Scheme 9). The fact that the wild-type titers of

Selective bromochlorination of a homoallylic alcohol for the total synthesis of (−)-anverene

• Frederick J. Seidl and
• Noah Z. Burns

Beilstein J. Org. Chem. 2016, 12, 1361–1365, doi:10.3762/bjoc.12.129

• limitation has inspired the development of several remote epoxidation methods for homoallylic and bishomoallylic alcohols [4][5], now allowing chemists to directly access a greater variety of enantioenriched epoxides. Several years ago our laboratory developed the first catalytic enantioselective

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

• convenient and cheap Brønsted acid, transformed a range of epoxides [20] into the corresponding nitrato alcohols. Shepson substituted ethylene oxide for commercially available isoprene epoxide and generated eight stereo- and structurally isomeric IPNs. Within this mixture 3° nitrate rac-7, 1° nitrate rac-8

Synthesis and in vitro cytotoxicity of acetylated 3-fluoro, 4-fluoro and 3,4-difluoro analogs of D-glucosamine and D-galactosamine

• Štěpán Horník,
• Lucie Červenková Šťastná,
• Petra Cuřínová,
• Jan Sýkora,
• Kateřina Káňová,
• Roman Hrstka,
• Ivana Císařová,
• Martin Dračínský and
• Jindřich Karban

Beilstein J. Org. Chem. 2016, 12, 750–759, doi:10.3762/bjoc.12.75

• :2,3-dianhydro-4-O-benzyl-β-D-mannopyranose (10, one of the Černý epoxides available from D-glucal [31][32][33] or levoglucosan [34]). Regioselective azidolysis [21][35][36] of 10 yielded 2-azido alcohol 11 which was converted to 12 by benzoylation at O-3 and debenzylation at O-4. To prevent azide

Photoinduced 1,2,3,4-tetrahydropyridine ring conversions

• Baiba Turovska,
• Henning Lund,
• Viesturs Lūsis,
• Anna Lielpētere,
• Edvards Liepiņš,
• Sergejs Beljakovs,
• Inguna Goba and
• Jānis Stradiņš

Beilstein J. Org. Chem. 2015, 11, 2166–2170, doi:10.3762/bjoc.11.234

• –carbon double bond in enamines to give the corresponding epoxides, however, in most cases they have not been isolated [36]. The hydroperoxide 2 reacts in the same way. Fission of the epoxide ring may be induced by the base itself producing 3. Attack of a second molecule of hydroperoxide 2 on the imine

Stereoselective synthesis of hernandulcin, peroxylippidulcine A, lippidulcines A, B and C and taste evaluation

• Marco G. Rigamonti and
• Francesco G. Gatti

Beilstein J. Org. Chem. 2015, 11, 2117–2124, doi:10.3762/bjoc.11.228

• double bonds of (+)-limonene or (−)-isopulegol with m-chloroperbenzoic acid (MCPBA) to introduce the stereogenic center at the C(2’) position. Unfortunately both methods were only modestly stereoselective and resulted in mixtures of the respective epoxides. These results implied a not simple column

Cross metathesis of unsaturated epoxides for the synthesis of polyfunctional building blocks

• Meriem K. Abderrezak,
• Kristýna Šichová,
• Nancy Dominguez-Boblett,
• Antoine Dupé,
• Zahia Kabouche,
• Christian Bruneau and
• Cédric Fischmeister

Beilstein J. Org. Chem. 2015, 11, 1876–1880, doi:10.3762/bjoc.11.201

Robust bifunctional aluminium–salen catalysts for the preparation of cyclic carbonates from carbon dioxide and epoxides

• Yuri A. Rulev,
• Zalina Gugkaeva,
• Victor I. Maleev,
• Michael North and
• Yuri N. Belokon

Beilstein J. Org. Chem. 2015, 11, 1614–1623, doi:10.3762/bjoc.11.176

• one-component aluminium-based catalysts for the reaction between epoxides and carbon dioxide have been prepared. The catalysts are composed of aluminium–salen chloride complexes with trialkylammonium groups directly attached to the aromatic rings of the salen ligand. With terminal epoxides, the

• achieving this goal is to produce cyclic carbonates or polycarbonates from carbon dioxide and the corresponding epoxides (Scheme 1). Cyclic carbonates are an important class of solvents [2] and starting materials in organic synthesis [3][4][5][6]. Although a significant array of catalysts have been

• developed for the production of cyclic carbonates [7][8][9] and polycarbonates [10][11] from carbon dioxide and epoxides, the most developed and privileged set of catalysts are based on Lewis acidic metal–salen complexes. In particular, cobalt(III) and chromium(III) complexes were found to be highly

Dicarboxylic esters: Useful tools for the biocatalyzed synthesis of hybrid compounds and polymers

• Ivan Bassanini,
• Karl Hult and
• Sergio Riva

Beilstein J. Org. Chem. 2015, 11, 1583–1595, doi:10.3762/bjoc.11.174

• . Telechelics with allyl-ether ends. Telechelics with ends functionalized as epoxides. Activated derivatives of dicarboxylic acids. Biocatalyzed synthesis of paclitaxel derivatives. Biocatalyzed synthesis of hybrid diesters 17 and 18. Hybrid derivatives of sylibin. Acknowledgements The authors acknowledge