Spatial effects in polymer chemistry

• Helmut Ritter

Beilstein J. Org. Chem. 2017, 13, 2015–2016, doi:10.3762/bjoc.13.198

• the carbonyl group of, e.g., poly(acrylates) show different IR signals when positioned side by side. If, for example, they are separated by styryl units, these carbonyl signals are clearly shifted. Such effects also play an important role in the reactivity of, e.g., ester-side groups. For example, the

Mechanochemical synthesis of small organic molecules

• Tapas Kumar Achar,
• Anima Bose and
• Prasenjit Mal

Beilstein J. Org. Chem. 2017, 13, 1907–1931, doi:10.3762/bjoc.13.186

• . They have also demonstrated a mechanochemical synthesis of 3-vinylindoles and β,β-diindolylpropionates by C–H activation. Substituted indoles and ethyl acrylates were reacted in presence of 10 mol % of Pd(OAc)2 and 1.2 equiv of MnO2 to afford highly substituted 3-vinylindoles using silica gel and

Phenylsilane as an effective desulfinylation reagent

• Wanda H. Midura,
• Aneta Rzewnicka and
• Jerzy A. Krysiak

Beilstein J. Org. Chem. 2017, 13, 1513–1517, doi:10.3762/bjoc.13.150

• sulfoxide substituent. Compounds 2 and 3 were obtained by us earlier [23] in diastereomerically pure form as key intermediates in our approach to constrained phosphonic acids by the reaction of phosphoryl acrylates with (S)-dimethylsulfonium(p-tolylsulfinyl)methylide. The carboxylate moiety was geminal to

Detection of therapeutic radiation in three-dimensions

• John A. Adamovics

Beilstein J. Org. Chem. 2017, 13, 1325–1331, doi:10.3762/bjoc.13.129

• their effective atomic number is not tissue equivalent. Acrylates, polyesters, polystyrenes and polycarbonates were also eliminated due to the relatively high exotherms created (>100 °C) during polymerization which prematurely oxidize the leuco dyes and rendered the dosimeter product unusable due to

Highly reactive, liquid diacrylamides via synergistic combination of spatially arranged curing moieties

• Maximilian Maier,
• Magnus S. Schmidt,
• Markus Ringwald and
• Christoph P. Fik

Beilstein J. Org. Chem. 2017, 13, 372–383, doi:10.3762/bjoc.13.40

• of new monomers and crosslinkers remained limited [4]. Mono-, di-, tri- and multifunctional (meth)acrylates are among the first choices for photopolymerized mixtures as they exhibit a favorable balance between reactivity and thermal stability upon storage [5][6][7]. Moreover, they comprise

3D printed fluidics with embedded analytic functionality for automated reaction optimisation

• Andrew J. Capel,
• Andrew Wright,
• Matthew J. Harding,
• George W. Weaver,
• Yuqi Li,
• Russell A. Harris,
• Steve Edmondson,
• Ruth D. Goodridge and
• Steven D. R. Christie

Beilstein J. Org. Chem. 2017, 13, 111–119, doi:10.3762/bjoc.13.14

• roughness and difficulty with removing un-melted powder from smaller cavities [6]. SL utilises layer-by-layer photopolymerisation of a liquid resin bath to generate fully dense polymer parts [21]. Typically these resins are complex formulations based around a small selection of UV-curable acrylates, epoxies

Iodination of carbohydrate-derived 1,2-oxazines to enantiopure 5-iodo-3,6-dihydro-2H-1,2-oxazines and subsequent palladium-catalyzed cross-coupling reactions

• Michal Medvecký,
• Igor Linder,
• Luise Schefzig,
• Hans-Ulrich Reissig and
• Reinhold Zimmer

Beilstein J. Org. Chem. 2016, 12, 2898–2905, doi:10.3762/bjoc.12.289

• -oxazine syn-11 in 41% yield. Next, we briefly studied 5-iodo-1,2-oxazine syn-4a as substrate in Heck reactions. The substrate was reacted with the alkyl acrylates 12a (R1 = Me) and 12b (R1 = t-Bu) under phosphine-free conditions [33][34] using 6 mol % of palladium(II) acetate, triethylamine as base and

• lithium chloride [35] leading to the expected coupling products syn-13 and syn-14 in 39% and 82% yield, respectively (Scheme 5). In both cases, only the E-configured 2-substituted alkyl acrylates were isolated. The moderate yield in the Heck reaction with methyl acrylate 12a is very likely caused by the

Experimental and theoretical insights in the alkene–arene intramolecular π-stacking interaction

• Valeria Corne,
• Ariel M. Sarotti,
• Carmen Ramirez de Arellano,
• Rolando A. Spanevello and
• Alejandra G. Suárez

Beilstein J. Org. Chem. 2016, 12, 1616–1623, doi:10.3762/bjoc.12.158

• , spectroscopic and computational evidence of the structurally related chiral acrylates to get new insights into the alkene–arene intramolecular interaction. Besides, it was evaluated the effect of the electron density of the aromatic counterpart and its influence on the asymmetric inductive capacity of the

• 40:60. The diastereomeric mixture of 4 and 5 was easily separated by flash chromatography. Finally, acrylates 6a,b were prepared by reaction of the corresponding alcohol 5 with acryloyl chloride in the presence of Et3N at 0 °C. The corresponding acrylic ester could not be obtained from the epimeric

• alcohols 4, probably because of the steric hindrance surrounding the alcohol position. Therefore, alcohols 4 were recycled by oxidation with PCC regenerating 3 in very good yields, and increasing the overall yield of acrylates 6. The 1H NMR spectra of compounds 6a and 6b (300 MHz, CDCl3) showed an

Conjugate addition–enantioselective protonation reactions

• James P. Phelan and
• Jonathan A. Ellman

Beilstein J. Org. Chem. 2016, 12, 1203–1228, doi:10.3762/bjoc.12.116

• , catalytically generated from 1, to α-substituted acrylates 2 followed by enantioselective protonation of the resulting lithium enolate (Scheme 1) [14]. The ortho-trimethylsilyl substituent on the phenyl ring was necessary for achieving high levels of enantioselectivity. All of the reactions proceeded in high

• (Scheme 2) [15][16][17]. A Mg-(bis)oxazoline complex serves as both a Lewis acid for the activation of α-substituted acrylates 6 towards radical addition and as a chiral template for an enantioselective hydrogen atom transfer from Bu3SnH to the α-ester radical intermediate. The authors found that the

• source in the stereodetermining step [27]. In 2012, Glorius and co-workers also reported the addition of aromatic aldehydes to α-carbon substituted acrylates 33 to provide differentiated 1,4-dicarbonyls 34b with good enantioselectivity [26]. When optimizing the catalyst‘s structure, the authors found

Cationic Pd(II)-catalyzed C–H activation/cross-coupling reactions at room temperature: synthetic and mechanistic studies

• Takashi Nishikata,
• Alexander R. Abela,
• Shenlin Huang and
• Bruce H. Lipshutz

Beilstein J. Org. Chem. 2016, 12, 1040–1064, doi:10.3762/bjoc.12.99

• arylureas at room temperature. A commercially available catalyst [Pd(MeCN)4](BF4)2 or a nitrile-free cationic palladium(II) complex generated in situ from the reaction of Pd(OAc)2 and HBF4, effectively catalyzes C–H activation/cross-coupling reactions between aryl iodides, arylboronic acids and acrylates

• expanded the substrate scope to include reactions with 3-alkyl-substituted ureas, as well as a wider variety of acrylates and even some acrylamides (Figure 4, 5d–h, conditions B). Many combinations of acrylates and more challenging arylureas, however, did not produce the desired product in satisfactory

• product was obtained exclusively. Under optimized conditions, various acrylates and amides can be synthesized via C–H activation reactions (Figure 6). Methyl acrylate, which did not show good general reactivity with arylureas under previous conditions, could be coupled in excellent yields (5i, 5j, 5k). As

Catalytic asymmetric synthesis of biologically important 3-hydroxyoxindoles: an update

• Bin Yu,
• Hui Xing,
• De-Quan Yu and
• Hong-Min Liu

Beilstein J. Org. Chem. 2016, 12, 1000–1039, doi:10.3762/bjoc.12.98

• maleimides, affording the corresponding products in excellent yields (up to 98% yield) and with excellent enantioselectivity (up to 94% ee, Scheme 37) [54]. Additionally, other activated alkenes such as methyl and ethyl acrylates and acrolein reacted smoothly with 7-azaisatins, giving the corresponding

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

• ’-Silyloxyenones as acceptors. As in the case of imidazolones, thiazolones also exhibit very poor reactivity in the Michael addition to methyl and tert-butyl acrylates. This problem could be circumvented by using α’-silyloxyenones as acrylate surrogates [73]. After catalyst screening and optimization of the

Application of 7-azaisatins in enantioselective Morita–Baylis–Hillman reaction

• Qing He,
• Gu Zhan,
• Wei Du and
• Ying-Chun Chen

Beilstein J. Org. Chem. 2016, 12, 309–313, doi:10.3762/bjoc.12.33

• allows a convenient approach to access multifunctional 3-hydroxy-7-aza-2-oxindoles with high enantiopurity (up to 94% ee). Other types of activated alkenes, such as acrylates and acrolein, could also be efficiently utilized. Keywords: 7-azaisatins; β-isocupreidine; bifunctional catalysis; maleimide; MBH

• acrolein catalyzed by β-isocupreidine (β-ICD) was reported by the Zhou group [5], isatin derivatives, as highly activated electrophiles, have been utilized by other groups for similar transformations with acrylates or acrylamides, affording the 3-hydroxyoxindole derivatives with moderate to excellent

• (Table 2, entries 13–15). To further assess the high electrophilicity of 7-azaisatins in MBH reactions, more activated alkenes were explored with 1a. Methyl and ethyl acrylates afforded products 3p and 3q, respectively, with comparable results to Wu’s work [7], albeit in a shorter time (24 h vs 2–3 d

Amino-functionalized (meth)acryl polymers by use of a solvent-polarity sensitive protecting group (Br-t-BOC)

• Helmut Ritter,
• Monir Tabatabai and
• Markus Herrmann

Beilstein J. Org. Chem. 2016, 12, 245–252, doi:10.3762/bjoc.12.26

• )-amino-protected monomers 2-((1-bromo-2-methylpropan-2-yl)oxycarbonylamino)ethyl (meth)acrylate 3a,b. For this purpose, 2-isocyanatoethyl (meth)acrylate 1a,b was reacted with 1-bromo-2-methylpropan-2-ol (2a). The free radical polymerization of (Br-t-BOC)-aminoethyl (meth)acrylates 3a,b yielded poly((Br-t

• )acrylates [2]. Therefore, for the synthesis of amino-containing (meth)acrylic monomers and polymers suitable amino-protecting groups are required. Classical protecting groups such as ammonium salts, F-MOC, Z- or t-BOC, respectively are readily available. Regarding to this aspect, we published some papers

Supramolecular polymer assembly in aqueous solution arising from cyclodextrin host–guest complexation

• Jie Wang,
• Zhiqiang Qiu,
• Yiming Wang,
• Li Li,
• Xuhong Guo,
• Duc-Truc Pham,
• Stephen F. Lincoln and
• Robert K. Prud’homme

Beilstein J. Org. Chem. 2016, 12, 50–72, doi:10.3762/bjoc.12.7

• the extent of intramolecular interactions between substituents in a single polymer chain and of intermolecular interactions between substituents in adjacent polymer chains. Consequently, the strength of interaction between the substituted poly(acrylates)s is substantially controlled by the variation

• % azobenzene-substituted poly(acrylate), PAAAzo, and two α-CD-substituted poly(acrylates) in which α-CD is substituted onto the poly(acrylate) backbone through either the C3- or C6-carbon of a D-glucopyranose subunit, PAA3α-CD and PAA6α-CD, respectively, which are 1.6 and 2.2% substituted (Figure 14) [67]. The

New metathesis catalyst bearing chromanyl moieties at the N-heterocyclic carbene ligand

• Agnieszka Hryniewicka,
• Szymon Suchodolski,
• Agnieszka Wojtkielewicz,
• Jacek W. Morzycki and
• Stanisław Witkowski

Beilstein J. Org. Chem. 2015, 11, 2795–2804, doi:10.3762/bjoc.11.300

• -deficient olefin (e.g., acrylates or acrylonitriles, type II or III). In these cases, full conversion and high yields can be achieved [18]. Although the problem with the CM reactions of olefins with electron-withdrawing groups, such as α,β-unsaturated ketones and esters, is partly solved [19][20], the

Bifunctional phase-transfer catalysis in the asymmetric synthesis of biologically active isoindolinones

• Antonia Di Mola,
• Maximilian Tiffner,
• Francesco Scorzelli,
• Laura Palombi,
• Rosanna Filosa,
• Paolo De Caprariis,
• Mario Waser and
• Antonio Massa

Beilstein J. Org. Chem. 2015, 11, 2591–2599, doi:10.3762/bjoc.11.279

• several methods to obtain rac-9 are available [32][33][34][35][36], it is worth noting that the asymmetric synthesis of 9 is one of the major obstacles when targeting the synthesis of chiral isoindolinones. The recently introduced intramolecular aza-Michael reactions of 2-substituted acrylates gave very

Copper-catalyzed stereoselective conjugate addition of alkylboranes to alkynoates

• Takamichi Wakamatsu,
• Kazunori Nagao,
• Hirohisa Ohmiya and
• Masaya Sawamura

Beilstein J. Org. Chem. 2015, 11, 2444–2450, doi:10.3762/bjoc.11.265

• alkenes with 9-BBN-H) to alkynoates to form β-disubstituted acrylates is reported. The addition occurred in a formal syn-hydroalkylation mode. The syn stereoselectivity was excellent regardless of the substrate structure. A variety of functional groups were compatible with the conjugate addition

• alkynoates might be possible through proton-trapping of an alkenylcopper intermediate. Herein, we report a copper-catalyzed conjugate addition of alkylboranes to alkynoates, providing a versatile approach to β-disubstituted acrylates [16][17][18][19]. The addition occurred in a formal syn-hydroalkylation

• acidic MeOH (vide infra). There was no reaction in the absence of a proton sourse. No hydroalkylation product at all could be found when alkyl-9-BBN 2a was replaced by (2-phenylethyl)boronic acid pinacolate ester; the substrates hardly reacted at all. A variety of β-disubstituted acrylates were

Self-assemblies of γ-CDs with pentablock copolymers PMA-PPO-PEO-PPO-PMA and endcapping via atom transfer radical polymerization of 2-methacryloyloxyethyl phosphorylcholine

• Jing Lin,
• Tao Kong,
• Lin Ye,
• Ai-ying Zhang and
• Zeng-guo Feng

Beilstein J. Org. Chem. 2015, 11, 2267–2277, doi:10.3762/bjoc.11.247

• copolymers in aqueous solution, a multimodal molecular weight distribution (which usually results from the addition of methacrylates to the polymers of acrylates) was not shown in the GPC curves of the PR-based multiblock copolymers [18][19]. Given that nearly the same quantity of 5–8 γ-CDs were left after

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

• various cross metathesis reactions, the phosphine-free Hoveyda type second generation Zhan catalyst-1B [30] was selected to conduct this transformation. A recent study by Fogg rationalized the superiority of the Hoveyda catalyst vs the Grubbs catalyst in cross metathesis with acrylates showing that the

Recent applications of ring-rearrangement metathesis in organic synthesis

• Sambasivarao Kotha,
• Milind Meshram,
• Priti Khedkar,
• Shaibal Banerjee and
• Deepak Deodhar

Beilstein J. Org. Chem. 2015, 11, 1833–1864, doi:10.3762/bjoc.11.199

• 28a,b) in excellent yields (82–92%). Involvement of acrylates 29a,b delivered lactones 30a,b in moderate yields (30a 41%, 30b 50%) upon treatment with catalyst 2 in dichloromethane at reflux conditions. However, 29a generated lactone 30a in 65% yield when the metathesis was performed using Grela’s

Reactions of nitroxides 15. Cinnamates bearing a nitroxyl moiety synthesized using a Mizoroki–Heck cross-coupling reaction

• Jerzy Zakrzewski and
• Bogumiła Huras

Beilstein J. Org. Chem. 2015, 11, 1155–1162, doi:10.3762/bjoc.11.130

• Jerzy Zakrzewski Bogumila Huras Institute of Industrial Organic Chemistry, Annopol 6, 03-236 Warsaw, Poland 10.3762/bjoc.11.130 Abstract Cinnamic acid derivatives bearing a nitroxyl moiety (2,2,6,6-tetramethyl-1-oxyl-4-piperidyl 3-E-aryl acrylates) were synthesized in 30–100% yield using a

• saturated aliphatic acids (instead of unsaturated ones as acrylates) are reacted with simple aromatic compounds (as benzene) in the presence of palladium(II) chloride [20]. Due to the important biological activity of cinnamates, the incorporation of a spin label moiety, particularly a nitroxyl fragment, is

Chemoselective O-acylation of hydroxyamino acids and amino alcohols under acidic reaction conditions: History, scope and applications

• Tor E. Kristensen

Beilstein J. Org. Chem. 2015, 11, 446–468, doi:10.3762/bjoc.11.51

• of such polymers prepared from side-chain-linked hydroxyproline or other hydroxyamino acids is their zwitterionic character, thereby separating them from more conventional amino acid acrylates prepared from the N-acylated amino acids. In the future, more resources could favourably be directed, by

Matsuda–Heck reaction with arenediazonium tosylates in water

• Ksenia V. Kutonova,
• Marina E. Trusova,
• Andrey V. Stankevich,
• Pavel S. Postnikov and
• Victor D. Filimonov

Beilstein J. Org. Chem. 2015, 11, 358–362, doi:10.3762/bjoc.11.41

• described by the group of Vallribera [9]. Arenediazonium tetrafluoroborates bearing only electron-donating groups (with the exception of chlorine) were effectively coupled with ethyl and tert-butyl acrylates only, while ethyl vinyl ketone, styrenes, allyl acetate, allyl benzene and methyl vinyl carbinol

• bromide [20] under harsh conditions with modest yields. The synthesized 3-chloropropyl cinnamates 3ba, 3bb, 3bg were not reported before. Styrene (1c) is less reactive than acrylates in Heck-type reactions. Notwithstanding, a range of stilbenes was synthesized stereoselectively with good yields and purity

New highlights of the syntheses of pyrrolo[1,2-a]quinoxalin-4-ones

• Emilian Georgescu,
• Alina Nicolescu,
• Florentina Georgescu,
• Florina Teodorescu,
• Daniela Marinescu,
• Ana-Maria Macsim and
• Calin Deleanu

Beilstein J. Org. Chem. 2014, 10, 2377–2387, doi:10.3762/bjoc.10.248

• [11] in presence of K2CO3 and triethylamine in DMF at 70 °C, or with activated alkenes, such as acrylates, acrylonitrile or diethyl malonate, in presence of triethylamine and an oxidant in DMF at 90 °C, led only to the normal cycloaddition products, i.e., pyrrolo[1,2-a]benzimidazoles [12]. When the