Radical chemistry in polymer science: an overview and recent advances

• Zixiao Wang,
• Feichen Cui,
• Yang Sui and
• Jiajun Yan

Beilstein J. Org. Chem. 2023, 19, 1580–1603, doi:10.3762/bjoc.19.116

• functionalization of optically active polymers [106]. Theato and co-workers introduced vinyl/alkyne-bearing poly(vinyl ether)s [107], poly(vinylcyclopropanes) [108], and poly(allyl 2-ylideneacetate) [109] as promising new platforms compatible to thiol–ene chemistry. Atom transfer radical addition (ATRA) is another

Synthesis of ether lipids: natural compounds and analogues

• Marco Antônio G. B. Gomes,
• Alicia Bauduin,
• Chloé Le Roux,
• Romain Fouinneteau,
• Wilfried Berthe,
• Mathieu Berchel,
• Hélène Couthon and
• Paul-Alain Jaffrès

Beilstein J. Org. Chem. 2023, 19, 1299–1369, doi:10.3762/bjoc.19.96

• alkenyl compounds, the vinyl ether function is characterized by a (Z)-configuration as shown in Figure 1. In addition, an acyl group is present on the secondary alcohol of the glycerol. This acyl group is constituted by a saturated or unsaturated lipid chain or, in the case of platelet-activating factor

Transition-metal-catalyzed domino reactions of strained bicyclic alkenes

• Austin Pounder,
• Eric Neufeld,
• Peter Myler and
• William Tam

Beilstein J. Org. Chem. 2023, 19, 487–540, doi:10.3762/bjoc.19.38

• state, followed by coordination to the alkyne generates intermediate 109. Migratory insertion of the alkyne results in the ruthenacycle 110. Subsequent reductive elimination generates putative allyl vinyl ether 111 and regenerates the active ruthenium complex. The allyl vinyl ether intermediate

Stepwise PEG synthesis featuring deprotection and coupling in one pot

• Logan Mikesell,
• Dhananjani N. A. M. Eriyagama,
• Yipeng Yin,
• Bao-Yuan Lu and
• Shiyue Fang

Beilstein J. Org. Chem. 2021, 17, 2976–2982, doi:10.3762/bjoc.17.207

• reaction, while the product of β-elimination of the tosylate – a vinyl ether – is inert under the reaction conditions. Compounds 3a–l were subjected to the study. All the compounds except 3h were found to be stable under the coupling conditions while product 5 was formed as indicated by TLC analysis

Cascade intramolecular Prins/Friedel–Crafts cyclization for the synthesis of 4-aryltetralin-2-ols and 5-aryltetrahydro-5H-benzo[7]annulen-7-ols

• Jie Zheng,
• Shuyu Meng and
• Quanrui Wang

Beilstein J. Org. Chem. 2021, 17, 1481–1489, doi:10.3762/bjoc.17.104

• -vinylphenyl)acetaldehyde (13a) using the route as outlined in Scheme 4. The synthesis started with the Wittig reaction of 2-bromobenzaldehyde (9a) with (methoxymethyl)triphenylphosphonium chloride (MTPPC) upon action with n-butyllithium in THF at 0 °C to give the vinyl ether 10a that was subjected to acidic

Recent progress in the synthesis of homotropane alkaloids adaline, euphococcinine and N-methyleuphococcinine

• Dimas J. P. Lima,
• Antonio E. G. Santana,
• Michael A. Birkett and
• Ricardo S. Porto

Beilstein J. Org. Chem. 2021, 17, 28–41, doi:10.3762/bjoc.17.4

• -carboxaldehyde, 9:1 77a/77b, 67% (after chromatographic separation); ii) butyl vinyl ether, Hg(OAc)2, (10 mol %), sealed tube, 130–135 °C, 79%; iii) vinylmagnesium bromide, −78 °C; iv) Dess–Martin periodinane, 83% over two steps; v) Grubbs catalyst 2nd gen., CH2Cl2, reflux, 74%; vi) 1. (PhSe)2, NaBH4, EtOH; 2

• ; 2. 1-heptyne; 3. I2, THF, 82%; ii) 1. n-BuLi, Et2O, −78 °C to 0 °C; 2. p-menthyl-3-carboxaldehyde, 5:1 (−)-87a / (−)-87b, 50% (after chromatographic separation); iii) butyl vinyl ether, Hg(OAc)2, (10 mol %), sealed tube, 130–135 °C, 79%; iv) vinylmagnesium bromide, −78 °C; v) Dess–Martin periodinane

All-carbon [3 + 2] cycloaddition in natural product synthesis

• Zhuo Wang and
• Junyang Liu

Beilstein J. Org. Chem. 2020, 16, 3015–3031, doi:10.3762/bjoc.16.251

• 64% yield over three steps. The conversion of 138 to sinensilactam A (20) was achieved in two steps. Platinum-catalyzed [3 + 2] cycloaddition The platinum-catalyzed intermolecular [3 + 2] cycloaddition of propargyl ether derivatives and vinyl ether producing polycyclic indoles was disclosed by

• Iwasawa and co-workers in 2011 [18][66] (Scheme 10A). Treatment of Boc-protected aniline 139 and n-butyl vinyl ether (140) with a platinum(II) catalyst afforded tricyclic indole 141 in 83% yield. The authors suggested that this catalytic [3 + 2] cycloaddition reaction may involve an α,β-unsaturated

• complex intermediate C. C is subjected to the nucleophilic attack of n-butyl vinyl ether (140) and generates alkenyl metallic intermediate D. Intramolecular nucleophilic attack onto the oxonium carbon of D affords the [3 + 2] cycloaddition product 141 with regeneration of the catalyst A. In 2020, Ye and co

Photosensitized direct C–H fluorination and trifluoromethylation in organic synthesis

• Shahboz Yakubov and
• Joshua P. Barham

Beilstein J. Org. Chem. 2020, 16, 2151–2192, doi:10.3762/bjoc.16.183

Recent synthesis of thietanes

• Jiaxi Xu

Beilstein J. Org. Chem. 2020, 16, 1357–1410, doi:10.3762/bjoc.16.116

• retention and inversion products [63] (Scheme 38). However, some olefins, such as cyclohexene, oct-1-ene, vinyl ether, vinyl sulfide, etc., produced 1,4-dithiane derivatives as products through the reaction of two molecules of thiobenzophenone (184a) and one molecule of the olefin under irradiation with 589

• 264 formed preferably, in the reaction of 256 with ethyl vinyl ether (215e) and propen-2-ylbenzene (186a). Notably, the photoreaction of 2,4-dithiobarbiturate 257 and 2,3-dimethylbut-2-ene (215a) produced exclusively the 4-thietane derivative 265 in 91% yield. 2,4,6-Trithiobarbiturate 258 reacted with

Synthesis of organic liquid crystals containing selectively fluorinated cyclopropanes

• Zeguo Fang,
• Nawaf Al-Maharik,
• Peer Kirsch,
• Matthias Bremer,
• Alexandra M. Z. Slawin and
• David O’Hagan

Beilstein J. Org. Chem. 2020, 16, 674–680, doi:10.3762/bjoc.16.65

• accomplished as illustrated in Scheme 3. Reduction of cyclohexanone 15 with NaBH4 gave cyclohexanol 16 in a ratio of 2:1. The major trans product 16a was purified as a single entity by column chromatography and was isolated in 45% yield. Vinyl ether 17 could be efficiently prepared using the methodology

• developed by Bosch [16]. Accordingly, treatment of 16a with butyl vinyl ether, bathophenanthroline (BPhen) and Et3N, using palladium(II) trifluoroacetate as a catalyst, gave vinyl ether 17 in 62% yield in a single step. Finally, difluorocarbene-mediated difluorocyclopropanation generated 10 in 50% yield

Tuning the stability of alkoxyisopropyl protection groups

• Zehong Liang,
• Henna Koivikko,
• Mikko Oivanen and
• Petri Heinonen

Beilstein J. Org. Chem. 2019, 15, 746–751, doi:10.3762/bjoc.15.70

• place practically instantaneous at room temperature with reagents 1a–d. In order to avoid formation of the vinyl ether analog as a side product, the reaction time should not exceed 5 minutes. The isolated yields of the protected nucleosides are typically between 70–90%. However, reagent 1e forms an

• of acetal synthesis. We also prepared the corresponding derivative 8b of thymidine and studied its hydrolytic stability separately. This is of some interest for discussion of mechanisms of acetal hydrolysis, since the vinyl ether intermediate 8b could probably be formed on the pathway shown in the

• during hydrolysis of 7c under these conditions. While going towards neutral conditions, the rate of the vinyl ether hydrolysis does not show a linear dependence on the acidity of the solution (see Suppporting Information File 1). Thus, at pH 6.8 the rate of hydrolysis of 8b is close to that of 7c and 7d

Application of olefin metathesis in the synthesis of functionalized polyhedral oligomeric silsesquioxanes (POSS) and POSS-containing polymeric materials

• Patrycja Żak and
• Cezary Pietraszuk

Beilstein J. Org. Chem. 2019, 15, 310–332, doi:10.3762/bjoc.15.28

• commercial availability. The choice of solvents is determined by the solubility of monomers, with methylene chloride, chloroform, and toluene being the most commonly used. Polymerization is terminated by addition of ethyl vinyl ether to the reaction mixture. Ruthenium residues from the obtained copolymer are

• complete conversion methyltetracyclododecene was added. The reaction was terminated with ethyl vinyl ether as soon as the second monomer was fully converted. A series of copolymers with different POSS-NBE content were obtained. The PDI values were in the range of 1.32–1.53 with average molecular weights of

Selective ring-opening metathesis polymerization (ROMP) of cyclobutenes. Unsymmetrical ladderphane containing polycyclobutene and polynorbornene strands

• Yuan-Zhen Ke,
• Shou-Ling Huang,
• Guoqiao Lai and
• Tien-Yau Luh

Beilstein J. Org. Chem. 2019, 15, 44–51, doi:10.3762/bjoc.15.4

• monomer 9 (Scheme 4). Synthesis of unsymmetrical ladderphane 8 by sequential ROMPs catalyzed by 6 Polymerization of monomer 9 in the presence of 10 mol % of 6 was performed in THF at 0 °C for 4 h, followed by quenching with ethyl vinyl ether to give polymer 14 in 86% yield (Scheme 5). It is worth noting

• . After stirring at 0 °C for 4 h, ethyl vinyl ether (1.0 mL) was then added and stirring was continued at 0 °C for 2 h. The mixture was concentrated and the residual solution was added to methanol. The precipitate was collected and redissolved in DCM. Reprecipitation by adding the DCM solution to methanol

• mg, 0.12 mmol) in DCM (40 mL) was added 6 (9.6 mg, 0.012 mmol) in DCM (5 mL). After stirring at rt for 4 h, ethyl vinyl ether (0.5 mL) was then added and stirring was continued for 30 min. The mixture was concentrated and the residual solution was added to methanol. The precipitate was collected and

Organometallic vs organic photoredox catalysts for photocuring reactions in the visible region

• Aude-Héloise Bonardi,
• Frédéric Dumur,
• Guillaume Noirbent,
• Jacques Lalevée and
• Didier Gigmes

Beilstein J. Org. Chem. 2018, 14, 3025–3046, doi:10.3762/bjoc.14.282

• good candidates for photooxidation of vinyl ether initiators. A Ru-based ROMP precatalyst: [Ru(IMesH2)(CF3CO2)(t-BuCN)4)]+ CF3CO2– which is a thermally stable photoredox catalyst has been also proposed in [110]. To finish, the RAFT polymerization can be also extended in a photocontrolled polymerization

Stereodivergent approach in the protected glycal synthesis of L-vancosamine, L-saccharosamine, L-daunosamine and L-ristosamine involving a ring-closing metathesis step

• Pierre-Antoine Nocquet,
• Aurélie Macé,
• Frédéric Legros,
• Jacques Lebreton,
• Gilles Dujardin,
• Sylvain Collet,
• Arnaud Martel,
• Bertrand Carboni and
• François Carreaux

Beilstein J. Org. Chem. 2018, 14, 2949–2955, doi:10.3762/bjoc.14.274

• speculated that the cyclic vinyl ether derivative I, with the prerequisite configuration of all stereogenic centers of the carbamate-protected glycal of L-vancosamine 1, could be obtained from the alcohol derivative II using an O-vinylation–ring-closing metathesis sequence (Figure 3). Afterwards, the

• vinyl ethers 15 [13][44][45][46]. We found that the best yields were obtained using Pd(TFA)2 and n-butyl vinyl ether as solvent in the presence of bathophenanthroline as ligand. In the case of Pd(OAc)2, the reaction was slower with moderate yields. The ring-closing metathesis reaction was performed with

Synthesis of eunicellane-type bicycles embedding a 1,3-cyclohexadiene moiety

• Alex Frichert,
• Peter G. Jones and
• Thomas Lindel

Beilstein J. Org. Chem. 2018, 14, 2461–2467, doi:10.3762/bjoc.14.222

• benzene partial structure. Preferred conformations of diastereomeric diols 18 and 19 including decisive NOESY correlations. Access to ketoester 14 that did not cyclize to the ethyl vinyl ether under McMurry conditions. Synthesis of the 1,3-cyclohexadiene-containing eunicellane-type [8.4.0]bicycle 18 by

The phenyl vinyl ether–methanol complex: a model system for quantum chemistry benchmarking

• Dominic Bernhard,
• Fabian Dietrich,
• Mariyam Fatima,
• Cristóbal Pérez,
• Hannes C. Gottschalk,
• Axel Wuttke,
• Ricardo A. Mata,
• Martin A. Suhm,
• Melanie Schnell and
• Markus Gerhards

Beilstein J. Org. Chem. 2018, 14, 1642–1654, doi:10.3762/bjoc.14.140

• Göttingen, Germany Institute of Physical Chemistry, Christian-Albrechts-Universität zu Kiel, Max-Eyth-Strasse 1, D-24118 Kiel, Germany 10.3762/bjoc.14.140 Abstract The structure of the isolated aggregate of phenyl vinyl ether and methanol is studied by combining a multi-spectroscopic approach and quantum

• -spectroscopic study to mixed aromatic olefinic ethers: in the case of phenyl vinyl ether (PVE), there is an ethenyl moiety replacing one of the phenyl rings compared to DPE. This introduces a localized π system along with the delocalized phenyl π system as hydrogen bond acceptor sites. Thereby, the complexity

• different binding motifs. In this paper, the first structural investigation on the complex of phenyl vinyl ether with methanol is presented. An established multi-spectroscopic approach [19][20] is used, coupling FTIR, IR/UV and microwave spectroscopy with theoretical treatments including dispersion

One hundred years of benzotropone chemistry

• Arif Dastan,
• Haydar Kilic and
• Nurullah Saracoglu

Beilstein J. Org. Chem. 2018, 14, 1120–1180, doi:10.3762/bjoc.14.98

• anhydride in benzene at 220 °C was reacted, [π2 + π8] cyclo-adduct 234 as a single product was isolated in 52% yield (Figure 9) [153][154]. The thermolysis of 230 in the presence of ethyl vinyl ether gave three volatile products 235–237 in GLC yields of 10%, 7%, and 15%, respectively (Figure 9) [154]. 5

On the design principles of peptide–drug conjugates for targeted drug delivery to the malignant tumor site

• Eirinaios I. Vrettos,
• Gábor Mező and
• Andreas G. Tzakos

Beilstein J. Org. Chem. 2018, 14, 930–954, doi:10.3762/bjoc.14.80

• , there are certain bonds like imine, oxime, hydrazone, orthoester, acetal, vinyl ether and polyketal [103] that are known to undergo hydrolysis at acidic pH, while being extremely stable during blood circulation. Therefore, acid-labile bonds could be hydrolyzed in the slightly acidic microenvironment and

Stepwise radical cation Diels–Alder reaction via multiple pathways

• Ryo Shimizu,
• Yohei Okada and
• Kazuhiro Chiba

Beilstein J. Org. Chem. 2018, 14, 704–708, doi:10.3762/bjoc.14.59

• pathways. Results and Discussion The present work began with the synthesis of the aryl vinyl ether 1 from p-propylphenol in 2 steps (Scheme S1 and Figure S1 in Supporting Information File 1). Both E- and Z-forms were readily purified by silica gel column chromatography. When the anodic oxidation of the Z

• reaction of the aryl vinyl ether 1 (Scheme 7). On the basis of the oxidation potentials, oxidative SET would selectively take place from the aryl vinyl ether 1 even in the presence of 2,3-dimethyl-1,3-butadiene (2) to generate the radical cation 1·+, in which the stereochemistry derived from the starting

• anodic oxidation of the Diels–Alder adduct 3 does not give either the retro-reaction product 1 or the vinylcyclobutane 4 and therefore, it seems that the overall transformation involves irreversible steps. Thus, the radical cation Diels–Alder reaction of aryl vinyl ether 1 effectively proceeds either via

Mannich base-connected syntheses mediated by ortho-quinone methides

• Petra Barta,
• Ferenc Fülöp and
• István Szatmári

Beilstein J. Org. Chem. 2018, 14, 560–575, doi:10.3762/bjoc.14.43

• presence of a large excess of ethyl vinyl ether as o-QM trapping agent, they isolated several 2-ethoxychromane derivatives 16. However, yields as low as 36% were found in some cases. o-QMs derived from Mannich adducts also appear to be key intermediates in the syntheses of biologically active natural

Intramolecular glycosylation

• Xiao G. Jia and
• Alexei V. Demchenko

Beilstein J. Org. Chem. 2017, 13, 2028–2048, doi:10.3762/bjoc.13.201

• -mannosylations [92]. In accordance with the linking strategy, the vinyl ether 70 was obtained in 98% yield from the corresponding 2-O-allyl ether 69 by the treatment with Wilkinson’s catalyst and BuLi (Scheme 17) [93]. Subsequent NIS-mediated tethering of 70 and acceptor 71 gave the tethered donor–acceptor pair

Kinetic analysis of mechanoradical formation during the mechanolysis of dextran and glycogen

• Naoki Doi,
• Yasushi Sasai,
• Yukinori Yamauchi,
• Tetsuo Adachi,
• Masayuki Kuzuya and
• Shin-ichi Kondo

Beilstein J. Org. Chem. 2017, 13, 1174–1183, doi:10.3762/bjoc.13.116

• microcrystalline cellulose powder through mechanocation polymerization with isobutyl vinyl ether in vacuum at 77 K [24]. The aforementioned mechanoanion was confirmed through tetracyanoethylene (TCNE) radical anion formation. The latter radical is produced by a single-electron transfer from the mechanoanion to

Multicomponent reactions: A simple and efficient route to heterocyclic phosphonates

• Mohammad Haji

Beilstein J. Org. Chem. 2016, 12, 1269–1301, doi:10.3762/bjoc.12.121

• this protocol for the preparation of phosphonodihydropyrans 163 or 164 starting from phosphonopyruvate 159 or phosphonopyruvamide 160, p-nitrobenzaldehyde (161) and ethyl vinyl ether (162) in a reactor equipped with a Dean–Stark separator (Scheme 35) [73]. The yields of the resulting cycloadducts 163

(Thio)urea-mediated synthesis of functionalized six-membered rings with multiple chiral centers

• Giorgos Koutoulogenis,
• Nikolaos Kaplaneris and
• Christoforos G. Kokotos

Beilstein J. Org. Chem. 2016, 12, 462–495, doi:10.3762/bjoc.12.48

• 8-oxabicyclo[3.2.1]octane 21 framework. In this reaction, the main factor of achieving high yields or enantioselectivities, is how electron-rich or electron-poor, the dienophile is. Electron-rich olefins, like the benzyl vinyl ether and ethyl vinyl ether, reacted with success providing high yields