Reaction of oxiranes with cyclodextrins under high-energy ball-milling conditions

• László Jicsinszky,
• Federica Calsolaro,
• Katia Martina,
• Fabio Bucciol,
• Maela Manzoli and
• Giancarlo Cravotto

Beilstein J. Org. Chem. 2019, 15, 1448–1459, doi:10.3762/bjoc.15.145

• especially useful when the crystalline complex formation with the guest is undesirable. The aggregation properties, by the ready-to-associate secondary rim, are considerably affected by these substituents. One of the most important reactions of CDs occurs with oxiranes (epoxides) under basic conditions to

• factors, but also by the lack of uniformity and the site-by-site variability of prepared CDPs, which have hampered the extensive CDP use. Mechanochemistry has proven to be a useful green tool in the hands of synthetic chemists [25][26][27][28]. The reaction of epoxides with cyclodextrins under green and

• optimisation. Results and Discussion Reaction of epoxides with CDs The reactions of oxiranes, particularly propylene oxide, with CDs in solution have been extensively studied and the products are synthesised on the ton-scale by various companies [6][30][31][32]. The reaction is based on the activation of

Synthesis of aryl cyclopropyl sulfides through copper-promoted S-cyclopropylation of thiophenols using cyclopropylboronic acid

• Emeline Benoit,
• Ahmed Fnaiche and
• Alexandre Gagnon

Beilstein J. Org. Chem. 2019, 15, 1162–1171, doi:10.3762/bjoc.15.113

• chloride to give the corresponding β-thioaryl ketone 4 [10]. Reacting 2 with epoxides results in the formation of the 1-(β-hydroxy)cyclopropyl aryl sulfides 5 [10] while reaction with formaldehydes [11] or aldehydes [12] affords 1-(arylthio)cyclopropylcarbinyl alcohols 6. Treating 6 with Burgess reagent or

Electrophilic oligodeoxynucleotide synthesis using dM-Dmoc for amino protection

• Shahien Shahsavari,
• Dhananjani N. A. M. Eriyagama,
• Bhaskar Halami,
• Vagarshak Begoyan,
• Marina Tanasova,
• Jinsen Chen and
• Shiyue Fang

Beilstein J. Org. Chem. 2019, 15, 1116–1128, doi:10.3762/bjoc.15.108

• protected with the 2-cyanoethyl group. These protecting groups and the linker have to be cleaved under strongly basic and nucleophilic conditions. As a result, many sensitive groups including acetal, hemiacetal, vinyl ethers, enol ethers, aldehydes, esters, activated esters, thioesters, aziridines, epoxides

Easy, efficient and versatile one-pot synthesis of Janus-type-substituted fullerenols

• Marius Kunkel and
• Sebastian Polarz

Beilstein J. Org. Chem. 2019, 15, 901–905, doi:10.3762/bjoc.15.87

• the characterization of Janus-type fullerenol amphiphiles more than one method is needed to perfectly identify the compounds. Polyhydroxylation reaction of the fullerene can lead to a mixture of several oxygen moieties like hydroxy groups, diols, ketones, hemiketals, epoxides and ethers. The general

Synthesis of acylglycerol derivatives by mechanochemistry

• Karen J. Ardila-Fierro,
• Andrij Pich,
• Marc Spehr,
• José G. Hernández and
• Carsten Bolm

Beilstein J. Org. Chem. 2019, 15, 811–817, doi:10.3762/bjoc.15.78

• epoxides, for which the maximum theoretical yield of the reaction is 50%. Here, however, the yield of the sn-1,3-protected monoacylglycerol was high, and consequently we expected the enantiomeric excess of the product to be low. This, assumption was confirmed by analysis of the sample by high-performance

Stereochemical investigations on the biosynthesis of achiral (Z)-γ-bisabolene in Cryptosporangium arvum

• Jan Rinkel and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2019, 15, 789–794, doi:10.3762/bjoc.15.75

• analysis of the preceeding epoxides, Figure S5, Supporting Information File 1) were purified by preparative HPLC on a chiral stationary phase to >99% ee for both samples (Figure S6, Supporting Information File 1), before converting them into the NPPs. For comparison, also racemic NPP was synthesised by a

• , labelling experiments for NMR assignment, synthetic procedures for the NPPs, Mosher ester analysis of epoxides, and chiral GC analysis of nerolidols. Supporting Information File 260: Experimental part. Acknowledgements This work was funded by the Deutsche Forschungsgemeinschaft (DI1536/7-1). We thank

Olefin metathesis in multiblock copolymer synthesis

• Maria L. Gringolts,
• Yulia I. Denisova,
• Eugene Sh. Finkelshtein and
• Yaroslav V. Kudryavtsev

Beilstein J. Org. Chem. 2019, 15, 218–235, doi:10.3762/bjoc.15.21

• (cyclohexene carbonate)s was carried out by the β-diiminate (BDI) zinc-catalyzed block copolymerization of functionalized epoxides and CO2 with a norbornenyl-containing initiator (Scheme 5) [68]. The subsequent “grafting through” by ROMP of norbornene resulted in the synthesis of multiblock copolymer brushes

Copolymerization of epoxides with cyclic anhydrides catalyzed by dinuclear cobalt complexes

• Yo Hiranoi and
• Koji Nakano

Beilstein J. Org. Chem. 2018, 14, 2779–2788, doi:10.3762/bjoc.14.255

• Yo Hiranoi Koji Nakano Department of Organic and Polymer Materials Chemistry, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan 10.3762/bjoc.14.255 Abstract The alternating copolymerization of epoxides with cyclic anhydrides (CAs) is a highly diverse

• turnover frequencies ever reported. A variety of epoxides and CAs were also found to be copolymerized successfully by the dinuclear cobalt complex with a high catalytic activity. Keywords: cobalt; copolymerization; cyclic anhydrides; epoxides; polyesters; Introduction Aliphatic polyesters have received

• alternating copolymerization of epoxides with cyclic anhydrides (CAs) is a promising alternative for polyester synthesis [11][12]. A broad range of epoxides and CAs are readily available and can be copolymerized through this method. Therefore, the polymer architectures and properties can be easily controlled

Synthesis of cis-hydrindan-2,4-diones bearing an all-carbon quaternary center by a Danheiser annulation

• Gisela V. Saborit,
• Carlos Cativiela,
• Ana I. Jiménez,
• Josep Bonjoch and
• Ben Bradshaw

Beilstein J. Org. Chem. 2018, 14, 2597–2601, doi:10.3762/bjoc.14.237

• corresponding carbonyl group (Scheme 4) was carried out by a two-step procedure involving epoxidation of the vinylsilane 5, followed by a rearrangement of the diastereomeric mixture of epoxides 7 induced by formic acid [34][35]. The resulting ketone 8 was obtained as a 3.5:1 mixture of epimers at C3. The

Learning from B₁₂ enzymes: biomimetic and bioinspired catalysts for eco-friendly organic synthesis

• Keishiro Tahara,
• Ling Pan,
• Toshikazu Ono and
• Yoshio Hisaeda

Beilstein J. Org. Chem. 2018, 14, 2553–2567, doi:10.3762/bjoc.14.232

• using various electrophiles such as alkyl halides [13], vinyl halides [14][15][16], aryl halides [17][18] and epoxides [19][20] in homogeneous solutions (Figure 1b). 1-2. Design of biomimetic and bioinspired B12 catalytic systems Schematic representations of B12 enzymes and enzyme-involving systems are

One-pot synthesis of epoxides from benzyl alcohols and aldehydes

• Edwin Alfonzo,
• Jesse W. L. Mendoza and
• Aaron B. Beeler

Beilstein J. Org. Chem. 2018, 14, 2308–2312, doi:10.3762/bjoc.14.205

• Edwin Alfonzo Jesse W. L. Mendoza Aaron B. Beeler Department of Chemistry, Boston University, Boston, Massachusetts 02215, United States 10.3762/bjoc.14.205 Abstract A one-pot synthesis of epoxides from commercially available benzyl alcohols and aldehydes is described. The reaction proceeds

• through in situ generation of sulfonium salts from benzyl alcohols and their subsequent deprotonation for use in Corey–Chaykovsky epoxidation of aldehydes. The generality of the method is exemplified by the synthesis of 34 epoxides that were made from an array of electronically and sterically varied

• alcohols and aldehydes. Keywords: Corey–Chaykovsky; epoxide; heterocycle; one-pot; ylide; Introduction Epoxides have historically served as strategic functional groups in target-oriented synthesis [1][2][3][4]. Common examples of their utility include stereospecific ring opening [5][6][7], rearrangements

Selective formation of a zwitterion adduct and bicarbonate salt in the efficient CO₂ fixation by N-benzyl cyclic guanidine under dry and wet conditions

• Yoshiaki Yoshida,
• Naoto Aoyagi and
• Takeshi Endo

Beilstein J. Org. Chem. 2018, 14, 2204–2211, doi:10.3762/bjoc.14.194

• fixation of CO2 such as cycloaddition of CO2 to various epoxides and synthesis of carbonate derivatives from CO2 and alcohols [6][7][8][9][10][11][12][13]. However, these kinds of catalysts often need high temperatures and pressure to completely achieve the CO2 fixation [6]. On the other hand, amidine and

• guanidine derivatives are well known as efficient catalysts for the cycloaddition of CO2 to epoxides at ambient temperature [7][14][15][16][17][18]. Previously, we reported that hydroiodides of amidine derivatives worked as significantly efficient catalysts for the cycloaddition of CO2 to epoxides under

• carbon dioxide without a water molecule. It is expected that the zwitterion adducts of guanidine derivatives and CO2 are not only efficient catalysts for cycloaddition of CO2 to epoxides but also a thermal latent curing agent for epoxy resin. Herein, we achieved selective formation of the zwitterionic

Functionalization of graphene: does the organic chemistry matter?

• Artur Kasprzak,
• Agnieszka Zuchowska and
• Magdalena Poplawska

Beilstein J. Org. Chem. 2018, 14, 2018–2026, doi:10.3762/bjoc.14.177

• epoxides’ opening by nucleophiles can therefore act as a competing side reaction in many coupling processes with the inclusion of graphene-family materials [9][16]. In other words, opening graphene-family material’s epoxides should be taken into account even when the crosslinker-based amidation or

• esterification approach is performed. The mechanism of opening graphene-family material’s epoxides is presented in Figure 4. This conversion involves a nucleophilic attack on the sp3 carbon, thus leading to the desired product. This functionalization route is simple, as it does not require coupling reagents

• . Strong nucleophiles (e.g., primary amines or thiols) react with epoxides more rapidly than do weak nucleophiles (e.g., like primary alcohols). This functionalization approach based on the epoxides’ opening enables the introduction of the reactive groups to the surfaces of graphene-family materials. The

Chiral bisoxazoline ligands designed to stabilize bimetallic complexes

• Deepankar Das,
• Rudrajit Mal,
• Nisha Mittal,
• Zhengbo Zhu,
• Thomas J. Emge and
• Daniel Seidel

Beilstein J. Org. Chem. 2018, 14, 2002–2011, doi:10.3762/bjoc.14.175

• -epoxides [16]. Trost et al. disclosed the synthesis of dinuclear zinc complexes 3 and their application to enantioselective Aldol reactions [17][18] and a host of other asymmetric transformations [18]. Other notable contributions in this area were provided by the groups of Martell [19][20], Maruoka [21][22

β-Hydroxy sulfides and their syntheses

• Mokgethwa B. Marakalala,
• Edwin M. Mmutlane and
• Henok H. Kinfe

Beilstein J. Org. Chem. 2018, 14, 1668–1692, doi:10.3762/bjoc.14.143

• . Regioselective epoxide ring opening and 1,2-difunctionalization of alkenes are the commonly employed routes in the synthesis of such compounds. Both strategies are discussed below. 3.1 Synthesis of β-hydroxy sulfides via regioselective ring opening of epoxides The considerable ring strain present in epoxides

• . 3.1.1 Thiols as nucleophiles. Thiols, in the presence of a wide variety of catalysts, yield sulfides upon opening of epoxides under a variety of reaction conditions and these have been comprehensively reviewed [19]. More catalysts and reaction conditions, novel or modern variations of the old, keep

• getting disclosed and are surveyed below. 3.1.1.1 Alumina catalysis. With respect to heterogeneous catalysts, Posner and Rogers reported that inactivated Woelm-200 chromatographic alumina catalyzes a regioselective and stereospecific (in favor of the trans-isomer) opening of a wide variety of epoxides by

Glycosylation reactions mediated by hypervalent iodine: application to the synthesis of nucleosides and carbohydrates

• Yuichi Yoshimura,
• Hideaki Wakamatsu,
• Yoshihiro Natori,
• Yukako Saito and
• Noriaki Minakawa

Beilstein J. Org. Chem. 2018, 14, 1595–1618, doi:10.3762/bjoc.14.137

• glycols, epoxides, and olefins takes place by the action of hypervalent iodine [38][71][72]. For example, Havare and Plattner reported the oxidative cleavage of α-aryl aldehydes using iodosylbenzene to give chain-shortened carbonyl compounds and formaldehyde [71]. In the field of carbohydrate chemistry

Direct electrochemical generation of organic carbonates by dehydrogenative coupling

• Tile Gieshoff,
• Vinh Trieu,
• Jan Heijl and
• Siegfried R. Waldvogel

Beilstein J. Org. Chem. 2018, 14, 1578–1582, doi:10.3762/bjoc.14.135

• polymer formation with less reactive epoxides (other than ethylene oxide) [7][8][9][10]. Electrochemistry has the capability to access products by extraordinary reaction pathways. Electric current is an inexpensive reagent and inherently safe reaction set-ups ensure a resource saving and applicable

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