Enabling technologies and green processes in cyclodextrin chemistry

• Giancarlo Cravotto,
• Marina Caporaso,
• Laszlo Jicsinszky and
• Katia Martina

Beilstein J. Org. Chem. 2016, 12, 278–294, doi:10.3762/bjoc.12.30

• in Scheme 10: CD-acryloyl derivative [60][61], β-CD/dye derivatives [31][62][63][64], CD-ionic liquid hybrids [65][66], CD-based iminosugar conjugates [67], water-soluble CD homo- and heterodimers [68][69], trimers [70][71] and oligomers [72] of α-, β- and γ-CD have all been successfully produced

Efficient synthetic protocols for the preparation of common N-heterocyclic carbene precursors

• Morgan Hans,
• Jan Lorkowski,
• Albert Demonceau and
• Lionel Delaude

Beilstein J. Org. Chem. 2015, 11, 2318–2325, doi:10.3762/bjoc.11.252

• tetrafluoroborate The one-pot synthesis of 1,3-dicyclohexylimidazolium chloride (ICy·HCl) was first disclosed in the open literature by Herrmann and co-workers in 1996 [47]. The reaction proceeded smoothly and the product did not show any tendency to form an ionic liquid, unlike its lower weight unsymmetrical

Grubbs–Hoveyda type catalysts bearing a dicationic N-heterocyclic carbene for biphasic olefin metathesis reactions in ionic liquids

• Maximilian Koy,
• Hagen J. Altmann,
• Benjamin Autenrieth,
• Wolfgang Frey and
• Michael R. Buchmeiser

Beilstein J. Org. Chem. 2015, 11, 1632–1638, doi:10.3762/bjoc.11.178

• solvent (toluene) and the ionic liquid (IL) 1-butyl-2,3-dimethylimidazolium tetrafluoroborate [BDMIM+][BF4−]. The structure of Ru-2 was confirmed by single crystal X-ray analysis. Keywords: biphasic catalysis; ionic initiators; recycling; ROMP; ruthenium; Introduction Ionic metathesis catalysts offer

• applying supported ionic liquid phase (SILP) technology [11]. We recently reported on different Ru-based ionic metathesis catalysts that can be used for these purposes. In these systems, the charge is either located directly at the ruthenium [11][12] or at the 1-methylpyridinium-4-carboxylate ligands that

• prepared from the neutral precursor RuCl2(H2ITap)(=CH–2-(2-PrO)-C6H4)) (Ru-1) and methyl trifluoromethanesulfonate. Also, an improved, high-yield synthesis of Ru-1 has been presented. Ru-2 was tested for its reactivity in ROMP under biphasic conditions using [BDMIM+][BF4−] as the ionic liquid and toluene

Pyridine-promoted dediazoniation of aryldiazonium tetrafluoroborates: Application to the synthesis of SF₅-substituted phenylboronic esters and iodobenzenes

• George Iakobson,
• Junyi Du,
• Alexandra M. Z. Slawin and
• Petr Beier

Beilstein J. Org. Chem. 2015, 11, 1494–1502, doi:10.3762/bjoc.11.162

• -coupling reactions with varied degree of success. The most efficient cross-coupling reactions were the Heck reactions with alkenes, a biaryl homocoupling reaction, an azo coupling to electron-rich arenes, and a dediazoniation with TMSN3 in an ionic liquid medium [74][75]. An efficient borylation of

Surprisingly facile CO₂ insertion into cobalt alkoxide bonds: A theoretical investigation

• Willem K. Offermans,
• Claudia Bizzarri,
• Walter Leitner and
• Thomas E. Müller

Beilstein J. Org. Chem. 2015, 11, 1340–1351, doi:10.3762/bjoc.11.144

• of cyclic carbonates. Two-step pathway for the cycloaddition of propylene oxide and CO2 in the ionic liquid 1-butyl-3-methylimidazolium chloride (bmim+ Cl−). Formation of copper(I) cyanoacetate for the activation of CO2. Activation of CO2 by nucleophilic attack of bromide in the Re(I)-catalysed

Quarternization of 3-azido-1-propyne oligomers obtained by copper(I)-catalyzed azide–alkyne cycloaddition polymerization

• Shun Nakano,
• Akihito Hashidzume and
• Takahiro Sato

Beilstein J. Org. Chem. 2015, 11, 1037–1042, doi:10.3762/bjoc.11.116

• the quarternized AP oligomer may be applied as a polymeric ionic liquid or a precursor of polymeric ionic liquids. In this study, we investigate quarternization of an AP oligomer with methyl iodide to obtain a soluble oligomer (Scheme 1b) and characterize the quarternized oligomer in dilute solutions

• . The conformation of oligoAPMe was further discussed based on the touched bead model. Since the oligoAPMe obtained in this study was solid and the iodide counterions were not significantly dissociated in DMSO, it is difficult to apply the oligoAPMe as a polymeric ionic liquid. However, if appropriate

Glycoluril–tetrathiafulvalene molecular clips: on the influence of electronic and spatial properties for binding neutral accepting guests

• Yoann Cotelle,
• Marie Hardouin-Lerouge,
• Stéphanie Legoupy,
• Olivier Alévêque,
• Eric Levillain and
• Piétrick Hudhomme

Beilstein J. Org. Chem. 2015, 11, 1023–1036, doi:10.3762/bjoc.11.115

• situ to the transient diene by reductive elimination using naked iodide [37][38][39] or the iodo-ionic liquid 1-butyl-3-methylimidazolium iodide [40]. After purification by column chromatography on silica gel, we noted that complete aromatization has occurred concomitantly and molecular clip 4 was

Radical-mediated dehydrative preparation of cyclic imides using (NH₄)₂S₂O₈–DMSO: application to the synthesis of vernakalant

• Dnyaneshwar N. Garad,
• Subhash D. Tanpure and
• Santosh B. Mhaske

Beilstein J. Org. Chem. 2015, 11, 1008–1016, doi:10.3762/bjoc.11.113

• dehydrating reagent for imide synthesis [27]. Several dehydrating conditions such as heating in ionic liquid at 140 °C, heating at 150–180 °C under microwave in various solvents, reaction with N,N'-disuccinimidyl oxalate followed by heating in trichloroethylene with 4-(dimethylamino)pyridine, Nb2O5

IR and electrochemical synthesis and characterization of thin films of PEDOT grown on platinum single crystal electrodes in [EMMIM]Tf₂N ionic liquid

• Andrea P. Sandoval,
• Marco F. Suárez-Herrera and
• Juan M. Feliu

Beilstein J. Org. Chem. 2015, 11, 348–357, doi:10.3762/bjoc.11.40

• , E-03080 Alicante, Spain 10.3762/bjoc.11.40 Abstract Thin films of PEDOT synthesized on platinum single electrodes in contact with the ionic liquid 1-ethyl-2,3-dimethylimidazolium triflimide ([EMMIM]Tf2N) were studied by cyclic voltammetry, chronoamperometry, infrared spectroscopy and atomic force

• reaction of PEDOT were studied using in situ FTIR spectroscopy. Keywords: AFM; [EMMIM]Tf2N ionic liquid; in situ IR; PEDOT; Pt single crystals; Introduction Conducting polymers have been subject of an intense research during the last decades because they exhibit high conductivity and interesting optical

• the fact that the viscosity of the ionic liquid is quite high [16]. It is important to state that the activation energy of the nucleation kinetics related to the ion exchange depends on the overpotential used. Even so, the results shown in Table 1, Figure 3a and Figure 4 show that the kinetics of the

Highly selective electrochemical fluorination of dithioacetal derivatives bearing electron-withdrawing substituents at the position α to the sulfur atom using poly(HF) salts

• Bin Yin,
• Shinsuke Inagi and
• Toshio Fuchigami

Beilstein J. Org. Chem. 2015, 11, 85–91, doi:10.3762/bjoc.11.12

• using ionic liquid poly(HF) salts such as Et3N·nHF and Et4NF·nHF (n = 3–5) as supporting electrolyte and fluorine source [9][10][11], and we have systematically studied the anodic fluorination of various heteroatom-containing compounds including heterocycles and macromolecules so far [12][13][14][15][16

Efficient CO₂ capture by tertiary amine-functionalized ionic liquids through Li⁺-stabilized zwitterionic adduct formation

• Zhen-Zhen Yang and
• Liang-Nian He

Beilstein J. Org. Chem. 2014, 10, 1959–1966, doi:10.3762/bjoc.10.204

• (mol CO2 absorbed per mol of base) through the formation of zwitterionic adducts being stabilized by Li+. Keywords: carbon capture and sequestration; CO2 chemistry; coordination effect; ionic liquid; polyethylene glycol; zwitterionic adducts; Introduction Carbon capture and sequestration (CCS) from

Supercritical carbon dioxide: a solvent like no other

• Jocelyn Peach and
• Julian Eastoe

Beilstein J. Org. Chem. 2014, 10, 1878–1895, doi:10.3762/bjoc.10.196

• additives. Focus has primarily been in surfactant and polymer design in water-in-CO2 (w/c) systems, however, attention is now beginning to expand into other alternative systems, including ionic liquid-in-CO2 systems [54][55][56] and the production of microstructures such as lamellar and bicontinuous phases

• chain surfactants, through reducing the contact of water and CO2. The greater stability of c/w films in comparison to air-in-water (a/w) was attributed to a smaller film size as well as smaller γ and π (surface pressure) values. Ionic liquid-in-scCO2: Room temperature ionic liquids (ILs) are organic

• in scCO2 through a computer simulation technique, which also gives evidence for the production of stable IL droplets within a continuous CO2 phase through amphiphilic surfactant addition. This study suggests that microemulsion stability is dependent on ionic liquid anion-surfactant headgroup

Multicomponent reactions in nucleoside chemistry

• Mariola Koszytkowska-Stawińska and
• Włodzimierz Buchowicz

Beilstein J. Org. Chem. 2014, 10, 1706–1732, doi:10.3762/bjoc.10.179

• rather limited. Zhang et al. obtained a series of pyrimidine nucleoside-thazolidinone hybrids 15 from 5-formyl-3',5'-di-O-acetyl-2'-deoxyuridine (14), an arylamine and mercaptoacetic acid (Scheme 6) [65]. The reactions were performed in a ionic liquid ([bmim]PF6). Products 15 were obtained in good to

• successful application of [bmim]BF4 as a solvent [91][92]. The use of the ionic liquid allowed to shorten the reaction time and resulted in much higher yields of the final compounds than those obtained from the reactions performed in conventional organic solvents [91]. Studies on recovery and reuse of [bmim

Cyclic phosphonium ionic liquids

• Sharon I. Lall-Ramnarine,
• Joshua A. Mukhlall,
• James F. Wishart,
• Robert R. Engel,
• Alicia R. Romeo,
• Masao Gohdo,
• Sharon Ramati,
• Marc Berman and
• Sophia N. Suarez

Beilstein J. Org. Chem. 2014, 10, 271–275, doi:10.3762/bjoc.10.22

• less conductive and have slightly smaller self-diffusion coefficients than their cyclic ammonium congeners. Keywords: cyclic phosphonium; ionic liquid; organophosphorus; phosphinanium; phospholanium; phosphonium; Introduction The most widely investigated and commercially available ionic liquids (ILs

Continuous-flow Heck synthesis of 4-methoxybiphenyl and methyl 4-methoxycinnamate in supercritical carbon dioxide expanded solvent solutions

• Phei Li Lau,
• Ray W. K. Allen and
• Peter Styring

Beilstein J. Org. Chem. 2013, 9, 2886–2897, doi:10.3762/bjoc.9.325

• catalysts also lend themselves particularly well to continuous processing. One such example is reported by Karbass et al. [26], who carried out continuous flow reaction using Pd(0) derived from [Pd3(OAc)6] supported on polymeric monoliths containing methylimidazole, an ionic-liquid (IL) moiety in near

A Lewis acid-promoted Pinner reaction

• Dominik Pfaff,
• Gregor Nemecek and
• Joachim Podlech

Beilstein J. Org. Chem. 2013, 9, 1572–1577, doi:10.3762/bjoc.9.179

• reaction with a 4 N hydrogen chloride solution in cyclopentyl methyl ether (CPME) [7]. An ionic liquid based on a sulfonic acid was used by Jiang et al. [8], where this method has only been applied to aliphatic nitriles. A transition metal-catalyzed Pinner reaction using dihydridotetrakis

Synthesis of guanidinium–sulfonimide ion pairs: towards novel ionic liquid crystals

• Martin Butschies,
• Manuel M. Neidhardt,
• Markus Mansueto,
• Sabine Laschat and
• Stefan Tussetschläger

Beilstein J. Org. Chem. 2013, 9, 1093–1101, doi:10.3762/bjoc.9.121

• Martin Butschies Manuel M. Neidhardt Markus Mansueto Sabine Laschat Stefan Tussetschlager Institut für Organische Chemie, Universität Stuttgart, Pfaffenwalring 55, 70569 Stuttgart, Germany 10.3762/bjoc.9.121 Abstract The recently introduced concept of ionic liquid crystals (ILCs) with

• sulfonimide anion directly attached to the mesogenic unit. Keywords: anion exchange; ionic liquid crystals; ion pairs; mesophases; sulfonimides; Introduction While ionic liquids, i.e., molten salts composed of either organic cation or anion (or both) with melting points far below 100 °C, are extensively

N-Heterocyclic carbene–palladium(II)-1-methylimidazole complex catalyzed Mizoroki–Heck reaction of aryl chlorides with styrenes

• Ting-Ting Gao,
• Ai-Ping Jin and
• Li-Xiong Shao

Beilstein J. Org. Chem. 2012, 8, 1916–1919, doi:10.3762/bjoc.8.222

• ) as the ionic liquid. Keywords: aryl chloride; Mizoroki–Heck reaction; N-heterocyclic carbene; palladium complex; synthetic method; Introduction The palladium-catalyzed reaction between organic halides and alkenes, the Mizoroki–Heck reaction, is one of the most versatile methods for the formation of

• product 4a was observed in all cases. It was reported that tetrabutylammonium bromide (TBAB), as a simple ionic liquid, possessing the advantages of low price and easy availability, can facilitate the NHC–Pd-complex-catalyzed Mizoroki–Heck reaction [29][30][31][33]. Thus, we then turned our interest to

Polysiloxane ionic liquids as good solvents for β-cyclodextrin-polydimethylsiloxane polyrotaxane structures

• Narcisa Marangoci,
• Rodinel Ardeleanu,
• Laura Ursu,
• Constanta Ibanescu,
• Maricel Danu,
• Mariana Pinteala and
• Bogdan C. Simionescu

Beilstein J. Org. Chem. 2012, 8, 1610–1618, doi:10.3762/bjoc.8.184

• Polymers, “Gheorghe Asachi” Technical University of Iasi, 700050 Iasi, Romania 10.3762/bjoc.8.184 Abstract An ionic liquid based on polydimethylsiloxane with imidazolium salt brushes was synthesized as a good solvent for β-cyclodextrin-polydimethylsiloxane rotaxane. As expected the PDMS-Im/Br ionic liquid

• had a liquid-like non-Newtonian behavior with rheological parameters dependent on frequency and temperature. The addition of rotaxane to the ionic liquid strengthened the non-Newtonian character of the sample and a type of stable liquid-like network was formed due to the contribution of weak ionic

• interactions. The structure is stable in the 20 to 80 °C domain as proved by the oscillatory and rotational rheological tests. Keywords: cyclodextrins; imidazolium salt; ionic liquid; polyrotaxanes; polysiloxanes; Introduction Ionic liquids (ILs) are environmentally friendly solvents with great potential for

Recyclable fluorous cinchona alkaloid ester as a chiral promoter for asymmetric fluorination of β-ketoesters

• Wen-Bin Yi,
• Xin Huang,
• Zijuan Zhang,
• Dian-Rong Zhu,
• Chun Cai and
• Wei Zhang

Beilstein J. Org. Chem. 2012, 8, 1233–1240, doi:10.3762/bjoc.8.138

• supported cinchona alkaloids have been developed as recyclable chiral promoters or organocatalysts. Among them, the Cahard group developed soluble polymer- and ionic-liquid-supported cinchona alkaloids for electrophilic fluorination [21][22]. The Fache and Soόs groups developed fluorous tag-attached

Regioselective chlorination and bromination of unprotected anilines under mild conditions using copper halides in ionic liquids

• Han Wang,
• Kun Wen,
• Nurbiya Nurahmat,
• Yan Shao,
• He Zhang,
• Chao Wei,
• Ya Li,
• Yongjia Shen and
• Zhihua Sun

Beilstein J. Org. Chem. 2012, 8, 744–748, doi:10.3762/bjoc.8.84

• liquids enable the title transformation to be achieved under mild conditions without the need for oxygen or gaseous HCl (Scheme 1). Results and Discussion We first used 2-methylaniline (2a) to explore and compare chlorination conditions using CuCl2 either in water or in an ionic liquid, with or without

• performed offline by passing either oxygen or simply air through the ionic liquid that contains the Cu(I)/Cu(II) mixture, to restore full reaction power. This important feature makes the chlorination in ionic liquids much more attractive than in aqueous HCl in terms of operational safety and environmental

• chlorination in ionic liquids, we also attempted to extend the reaction to other halides. While attempts to use fluoride and iodide failed, bromination was successfully achieved in high yields and regioselectivity, in an ionic liquid with bromide as a counter ion (Table 3). In general, the reaction time for

Efficient and selective chemical transformations under flow conditions: The combination of supported catalysts and supercritical fluids

• M. Isabel Burguete,
• Eduardo García-Verdugo and
• Santiago V. Luis

Beilstein J. Org. Chem. 2011, 7, 1347–1359, doi:10.3762/bjoc.7.159

• and the recycling of the IL phase containing the catalyst [44]. The IL–scCO2 system shows a specific phase behavior where CO2 can dissolve significantly into the IL phase, but no ionic liquid dissolves in the scCO2. Thus, the phase behavior of IL–scCO2 systems, including the partitioning of organic

• commercial inorganic support, allowing mild reaction conditions and making the use of organic solvents or additional purification steps unnecessary (Scheme 3b). Thus, the commercially available (Sa,Rc)-1-naphthyl-QUINAPHOS in the ionic liquid [EMIM][NTf2] gave the best results for the SILP-catalyst system

• were achieved for the second step (17–35%) the corresponding acetate was obtained in high enantiomeric purity (ca. 99%). b) Biocatalysts immobilized in ionic liquids (ILs) The discovery of the possibility to immobilize biocatalysts in ionic-liquid phases has been a recent breakthrough that can be

Amine-linked diglycosides: Synthesis facilitated by the enhanced reactivity of allylic electrophiles, and glycosidase inhibition assays

• Ian Cumpstey,
• Jens Frigell,
• Elias Pershagen,
• Tashfeen Akhtar,
• Elena Moreno-Clavijo,
• Inmaculada Robina,
• Dominic S. Alonzi and
• Terry D. Butters

Beilstein J. Org. Chem. 2011, 7, 1115–1123, doi:10.3762/bjoc.7.128

• aminated amine-linked sec–sec structures by aziridine-opening reactions (ionic liquid, 120 °C) [9]. Primary–sec amine-linked structures have been synthesised by Thiem et al., through a reductive amination strategy [10][11]. In contrast, related structures containing an amine linkage between a carbohydrate

Construction of cyclic enones via gold-catalyzed oxygen transfer reactions

• Leping Liu,
• Bo Xu and
• Gerald B. Hammond

Beilstein J. Org. Chem. 2011, 7, 606–614, doi:10.3762/bjoc.7.71

• the diacid 1,6-diyne (R1 = R2 = COOH) was employed in the reaction, only the esterified product (R1 = R2 = COOMe) was isolated, albeit in low yield. The authors also carried out this gold-catalyzed transformation in an ionic liquid [49]. This modification enabled the separation of the gold catalyst

• from the organic mixture and the recovered gold catalyst in the ionic liquid was re-used as many as five times without loss of activity. A hydrolysis/cyclization mechanism was proposed for the transformation (Scheme 13). Although this mechanism is plausible, another option for the cyclization step

Surfactant catalyzed convenient and greener synthesis of tetrahydrobenzo[a]xanthene-11-ones at ambient temperature

• Pravin V. Shinde,
• Amol H. Kategaonkar,
• Bapurao B. Shingate and
• Murlidhar S. Shingare

Beilstein J. Org. Chem. 2011, 7, 53–58, doi:10.3762/bjoc.7.9

• NaHSO4.SiO2 [18], strontium triflate [19], Zr(HSO4)4 [20], dodecatungstophosphoric acid (PWA) [21], iodine [22], InCl3/P2O5 [23] and p-toluenesulfonic acid/ionic liquid([bmim]BF4) [24] have been employed for their synthesis. However, in an era where green methods are desirable many of these methods are