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

• through formation of zwitterionic adducts, combining synthetic strategies to ionic liquids (ILs) and coordination. The essence of our strategy is to make use of multidentate cation coordination between Li+ and an organic base. Also PEG-functionalized organic bases were employed to enhance the CO2

• . These efforts include the development of liquid and solid absorbents and membranes [2][3][4][5][6][7]. Ionic liquids (ILs), which have attractive properties such as negligible vapor pressure, a wide liquid temperature ranges, good thermal stability, high ionic conductivity, and versatile solvation

• ). Notably, equimolar CO2 absorption was obtained using task-specific ionic liquids (TSILs) with the phosphonium cation containing long alkyl chains and anions derived from AAs (prolinate and methioninate) [36], or AA salts with bulky N-substituents in polyethylene glycol (PEG) solution [37]. However

Relay cross metathesis reactions of vinylphosphonates

• Raj K. Malla,
• Jeremy N. Ridenour and
• Christopher D. Spilling

Beilstein J. Org. Chem. 2014, 10, 1933–1941, doi:10.3762/bjoc.10.201

• 14b. Analysis of the TBAI allylation mechanism suggested that a good approach to mono-allyl phosphonate 14a would be a stoichiometric demethylation followed by a rapid allylation under ambient conditions. During the synthesis of phosphonate based ionic liquids, Sachnov et al. showed that

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

• 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

•  9). Ionic liquids solubilised included 1,1,3,3-tetramethylguanidinium acetate (TMGA, compound 46, Figure 9), 1,1,3,3-tetramethylguanidinium lactate (TMGL, compound 47, Figure 9) and 1,1,3,3-tetramethylguanidinium trifluoroacetate (TMGT, compound 48, Figure 9). Additives such as methyl orange, CoCl2

Comparing kinetic profiles between bifunctional and binary type of Zn(salen)-based catalysts for organic carbonate formation

• Carmen Martín and
• Arjan W. Kleij

Beilstein J. Org. Chem. 2014, 10, 1817–1825, doi:10.3762/bjoc.10.191

• attractive reaction conditions. Over the past years many different catalytic systems have been developed for this kind of process exemplifying the huge interest in the synthesis of cyclic carbonates and these catalysts include quaternary ammonium salts [12], ionic liquids [13][14] and metal-based catalysts

• coupling reactions are essential to control the process selectivity (cyclic versus polycarbonate formation, Scheme 1) and to improve the activity of the used catalysts. Several computational investigations have been reported in this area focusing on catalysts comprising ionic liquids [30], N-heterocyclic

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

• , such as microwave irradiation, ionic liquids or inorganic supports, or (ii) the development of novel MCRs leading to nucleoside analogs bearing an unconventional nucleobase. As reports dealing with these issues revealed, a combination of both these trends may result in the preparation of structurally

Clicked and long spaced galactosyl- and lactosylcalix[4]arenes: new multivalent galectin-3 ligands

• Silvia Bernardi,
• Paola Fezzardi,
• Gabriele Rispoli,
• Stefania E. Sestito,
• Francesco Peri,
• Francesco Sansone and
• Alessandro Casnati

Beilstein J. Org. Chem. 2014, 10, 1672–1680, doi:10.3762/bjoc.10.175

• temperature could afford divalent and tetravalent glycocalixarenes in very high yields and regioselectivity. Following these studies, a wide series of other examples appeared in the literature [18][36][37][38][39] also exploiting the use of microwaves, ionic liquids and protected or even deprotected [17

Preparation of phosphines through C–P bond formation

• Iris Wauters,
• Wouter Debrouwer and
• Christian V. Stevens

Beilstein J. Org. Chem. 2014, 10, 1064–1096, doi:10.3762/bjoc.10.106

• obtained was 45%. The same group has shown that imidazolium based ionic liquids can be used as a medium to perform the C–P cross-coupling reactions. This method allows an easy separation of the product from the catalyst and the recycling of the palladium catalyst [176]. Stelzer and co-workers have

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

• , Brooklyn College of the City University of New York, 2900 Bedford Avenue, Brooklyn, NY 11210, USA, Fax: +1 718-951-4407, Tel +1 718-951-5000, ext. 2869 10.3762/bjoc.10.22 Abstract Ionic liquids (ILs) incorporating cyclic phosphonium cations are a novel category of materials. We report here on the

• 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

• butylphenylphospholanium (C4PhPphol NTf2) and butylphenylphosphinanium (C4PhPphin NTf2) ionic liquids are examples of a rare class of ILs with direct attachment of the aryl group to the cationic center. We were unable to find any information on ILs containing analogous nitrogen-centered cations for comparison, although

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

• biphasic mode using a mixture of solvents, such as ethylene glycol and toluene [8]. The drive to carry out reactions in environmentally benign media also led to studies being carried out in “green” (environmentally friendly) solvents, such as aqueous media, some supercritical fluids (SCFs), ionic liquids

Stability of SG1 nitroxide towards unprotected sugar and lithium salts: a preamble to cellulose modification by nitroxide-mediated graft polymerization

• Guillaume Moreira,
• Laurence Charles,
• Mohamed Major,
• Florence Vacandio,
• Yohann Guillaneuf,
• Catherine Lefay and
• Didier Gigmes

Beilstein J. Org. Chem. 2013, 9, 1589–1600, doi:10.3762/bjoc.9.181

• the loss of the initial polysaccharide, namely cellulose. Another strategy that has drawn interest in the scientific community is the use of ionic liquids [14]. However, these solvents usually are very expensive or must be specifically synthesized. A more convenient media, which has proven to be

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

• 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

• used as designer solvents, electrolytes for lithium ion batteries, dye-sensitized solar cells, and the electrochemical deposition of metals [1][2][3][4][5], the corresponding ionic liquids with thermotropic liquid-crystalline properties, i.e., ILCs, are a much younger class of compounds [6][7][8

• Seddon and Bruce [13]. Regarding ionic liquids, sulfonimides have been used in various ways. Particularly interesting is the symmetrical bistriflimide anion [14], which leads to desirable properties such as hydrolytic stability, low viscosity or low melting points in the ionic liquids [1][4][15][16][17

Appel-reagent-mediated transformation of glycosyl hemiacetal derivatives into thioglycosides and glycosyl thiols

• Tamashree Ghosh,
• Abhishek Santra and
• Anup Kumar Misra

Beilstein J. Org. Chem. 2013, 9, 974–982, doi:10.3762/bjoc.9.112

• agents (triphenylphosphine or combination of triethylsilane and BF3·OEt2) followed by the reaction of the in situ generated thiolate ions with glycosyl bromides under phase-transfer conditions [23] or in ionic liquids [24]; (b) reaction of glycosyl bromides with thiols under phase-transfer conditions [25

1-n-Butyl-3-methylimidazolium-2-carboxylate: a versatile precatalyst for the ring-opening polymerization of ε-caprolactone and rac-lactide under solvent-free conditions

• Astrid Hoppe,
• Faten Sadaka,
• Claire-Hélène Brachais,
• Gilles Boni,
• Jean-Pierre Couvercelle and
• Laurent Plasseraud

Beilstein J. Org. Chem. 2013, 9, 647–654, doi:10.3762/bjoc.9.73

• (DMC) with imidazole derivatives, making them very attractive and accessible compounds [35]. Therefore, they found applications as ligands in organometallic catalysis [36][37][38][39][40][41], as precursors of halide-free ionic liquids [42][43][44][45], and as organocatalysts in reactions involving

Chemoenzymatic synthesis and biological evaluation of enantiomerically enriched 1-(β-hydroxypropyl)imidazolium- and triazolium-based ionic liquids

• Paweł Borowiecki,
• Małgorzata Milner-Krawczyk and
• Jan Plenkiewicz

Beilstein J. Org. Chem. 2013, 9, 516–525, doi:10.3762/bjoc.9.56

• or iodides, yielding novel optically active ionic liquids. Racemic salts were tested against a wide range of microorganisms. Keywords: antibiotics; antifungal agents; double derivatization; enzyme catalysis; ionic liquids; Introduction Aromatic heterocycles play a crucial role in medicinal

• -derived ionic liquids (ILs), as well as their chiral derivatives (CILs). CILs have become a subject of intensive study since their potential as catalysts for asymmetric induction [32][33][34], as supplements for influencing reaction stereoselectivity [35], as chiral solvents in stereoselective

• liquids to exhibit excellent antimicrobial activity, raising the possibility that ionic liquids could find application as biocidal agents in the control of microorganism growth [42][43][44][45]. Herein, we report the results of our investigation on the chemoenzymatic synthesis of new chiral ionic liquids

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

• chlorides and styrenes under air at 140 °C within 12 h. Various activated and deactivated aryl chlorides work well under the optimal reaction conditions. In addition, TBAB, as a “green solvent” and one of the most advantageous ionic liquids due to its low price and availability, was used as the solvent to

Imidazolinium and amidinium salts as Lewis acid organocatalysts

• Oksana Sereda,
• Nicole Clemens,
• Tatjana Heckel and
• René Wilhelm

Beilstein J. Org. Chem. 2012, 8, 1798–1803, doi:10.3762/bjoc.8.205

• desulfurization of the products containing a thiol or thiocarbonyl group. Keywords: Diels–Alder; ionic liquids; organocatalysis; soft Lewis acids; thiiranes; thioesters; Introduction Salts with melting points below 100 °C are known as ionic liquids and are often used as novel solvents for reactions and

• electrochemical processes [1]. Several of these solvents can contribute to the research field of “green chemistry” [2]. The most common used ionic liquids are based on imidazolium cations. Next to their application in catalytic reactions [3][4][5][6], they are also capable of catalyzing reactions themselves

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

• 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

• , even if each component of their structure is soluble in a large number of solvents [8]. Research for new solvents has led to the discovery of ionic liquids as a good option for pseudo- or polyrotaxane structures [7][8][17][18]. It should be also mentioned that the mobility of the carrier ions of ILs

• , high chain flexibility, good thermal, oxidative and UV stability, high gas permeability, surface activity, hydrophobicity, etc., is the class of polysiloxanes, especially polydimethylsiloxanes [24]. It is worth mentioning that ionic liquids based on polydimethylsiloxane and imidazolium salt groups have

Impact of cyclodextrins on the behavior of amphiphilic ligands in aqueous organometallic catalysis

• Hervé Bricout,
• Estelle Léonard,
• Christophe Len,
• David Landy,
• Frédéric Hapiot and
• Eric Monflier

Beilstein J. Org. Chem. 2012, 8, 1479–1484, doi:10.3762/bjoc.8.167

• products. Traditional solvents have especially been incriminated due to the pollution problems they raise. Thus, in the context of increased awareness about environmental safety, nonconventional media appeared to be a promising alternative to toxic solvents. The use of supercritical fluids, ionic liquids

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

• Science, Shanghai, 201620, China 10.3762/bjoc.8.84 Abstract By using ionic liquids as solvents, the chlorination or bromination of unprotected anilines at the para-position can be achieved in high yields with copper halides under mild conditions, without the need for potentially hazardous operations such

• as supplementing oxygen or gaseous HCl. Keywords: halogenation; ionic liquids; oxydation; regioselectivity; solvent effects; Introduction Chlorination and bromination of aromatic rings are classical and widely performed transformations, which are useful in many multistep organic-synthesis

• transformation that do not require the use of aqueous or gaseous HCl and oxygen gas. Our search for suitable conditions focused on the use of ionic liquids as solvents. The amount of research into the application of ionic liquids in organic synthesis has experienced a dramatic expansion over the past decade

Synthesis of mesomeric betaine compounds with imidazolium-enolate structure

• Nina Gonsior,
• Fabian Mohr and
• Helmut Ritter

Beilstein J. Org. Chem. 2012, 8, 390–397, doi:10.3762/bjoc.8.42

• ) with different halide-containing quinone derivatives and subsequent hydrolysis [11]. Since the quaternization reaction is very common for imidazole chemistry, e.g., synthesis of ionic liquids, we investigated the quaternization reaction of three different imidazole compounds with tetrabromo-1,4

Coupled chemo(enzymatic) reactions in continuous flow

• Ruslan Yuryev,
• Simon Strompen and
• Andreas Liese

Beilstein J. Org. Chem. 2011, 7, 1449–1467, doi:10.3762/bjoc.7.169

• immobilized Candida antarctica lipase B (Novozym 435) was used as a heterogeneous catalyst in the kinetic resolution of the alcohol 22 [30]. Racemization of the unreacted (S)-22 was achieved with acidic zeolite catalysts. Both heterogenous catalysts were coated with ionic liquids for improved stability of the

Amines as key building blocks in Pd-assisted multicomponent processes

• Didier Bouyssi,
• Nuno Monteiro and
• Geneviève Balme

Beilstein J. Org. Chem. 2011, 7, 1387–1406, doi:10.3762/bjoc.7.163

• conducted in phosphonium salt-based ionic liquids (PSILs) with PdCl2(PPh3)2/CuI/DBU as the catalyst system [30]. In this case, the palladium-mediated Sonogashira coupling reaction leading to 1-halo-2-alkynylbenzene derivatives is followed by a carboxyamidation in the presence of carbon monoxide and primary

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

• provide simple tools for a rapid optimization of reaction parameters and facilitate the development of efficient flow processes [23][24][25]. Neoteric solvents (scFs, ionic liquids, PEG, etc.) have been considered as “green” alternative solvents due to their properties. However, in order to consider a

• ligands allowed the authors to obtain a system based on the ligand Josiphos, providing a higher enantioselectivity (83% ee at 55 °C) than the corresponding homogeneous system dissolved in scCO2 [42]. b) Catalysts immobilized in ionic liquids (ILs) The immobilization of a catalyst in an IL phase has been

• in ionic liquids (ILs) The immobilization of a Rh hydroformylation catalyst in [BMIM][PF6] has been reported by Cole-Hamilton to produce a significant decrease in the aldehyde selectivity, relative to toluene, while retaining the conversion and the l/b selectivity [60][61]. Changing to a scCO2–IL

Recent advances in the gold-catalyzed additions to C–C multiple bonds

• He Huang,
• Yu Zhou and
• Hong Liu

Beilstein J. Org. Chem. 2011, 7, 897–936, doi:10.3762/bjoc.7.103

• solvents, an attractive alternative is the use of ionic liquids as the reaction solvent, which often affords inexpensive, recyclable (and therefore environmentally benign), and sustainable catalyst systems. For example, Aksin et al. demonstrated that ionic liquids were highly suitable reaction media for

Studies on Pd/NiFe₂O₄ catalyzed ligand-free Suzuki reaction in aqueous phase: synthesis of biaryls, terphenyls and polyaryls

• Sanjay R. Borhade and
• Suresh B. Waghmode

Beilstein J. Org. Chem. 2011, 7, 310–319, doi:10.3762/bjoc.7.41

• a variety of support materials (e.g., carbon, metal oxides, zeolites, clays, polymers, diatomite and graphite oxide) as well as in ionic liquids [22][23][24][25][26][27][28][29][30][31][32]. In addition, efforts were also made to replace the environmentally harmful organic solvents by eco-friendly