A new intermediate in the Prins reaction

• Shinichi Yamabe,
• Takeshi Fukuda and
• Shoko Yamazaki

Beilstein J. Org. Chem. 2013, 9, 476–485, doi:10.3762/bjoc.9.51

• produced when pinene (a bicyclic monoterpene) was heated with paraformaldehyde. However, Prins performed the first rather comprehensive study of the reactions between formaldehyde and hydrocarbons with C=C double bonds [2][3]. These were styrene, pinene, camphene and anethole. As a catalyst, sulfuric acid

• , because the constituent atoms are only C, H and O in the original system, and it is a fundamental organic reaction. In this work, as the first attempt, reactions paths were traced by DFT calculations under Prins’ original conditions (styrene and formaldehyde in the acidic aqueous media). As an alkene

• , propene was also employed for comparison. From styrene, 4-phenyl-1,3-dioxane was obtained in 86% yield, and from propene 4-methyl-1,3-dioxane in 65% yield (based on H2C=O) [4]. The target of this work is to check whether the seemingly established mechanism shown in Scheme 5 holds for the two alkenes and

Inter- and intramolecular enantioselective carbolithiation reactions

• Asier Gómez-SanJuan,
• Nuria Sotomayor and
• Esther Lete

Beilstein J. Org. Chem. 2013, 9, 313–322, doi:10.3762/bjoc.9.36

• in different ways, to avoid this polymerization (Scheme 1). The first examples of intermolecular enantioselective carbolithiations of styrene derivatives were reported by Normant and Marek [9], taking advantage of the complex-induced proximity effect (CIPE). Thus, the addition of primary and

• alcohol (9) with the complex of butyllithium/diamine L2 in cumene at 0 °C, obtaining alcohol (R)-11 in 71% yield with 71% ee (Scheme 3). This is essentially opposite to the enantioselectivity obtained previously with (−)-sparteine L1 (82% yield, 83% ee in favor of (S)-11) [10]. Substituted styrene

• fully developed. On the other hand, the high reactivity of the organolithiums requires the use of stoichiometric amounts of the chiral ligand. Intermolecular carbolithiation. Carbolithiation of cinnamyl and dienyl derivatives. Carbolithiation of cinnamyl alcohol. Carbolithiation of styrene derivatives

Recent advances in transition-metal-catalyzed intermolecular carbomagnesiation and carbozincation

• Kei Murakami and
• Hideki Yorimitsu

Beilstein J. Org. Chem. 2013, 9, 278–302, doi:10.3762/bjoc.9.34

•  37). Although the cobalt-catalyzed allylzincation reactions of dialkylacetylenes resulted in low yield, the reactions of arylacetylenes provided various tri- or tetrasubstituted styrene derivatives (Scheme 38) [119][120]. Kambe reported a rare example of silver catalysis for carbomagnesiation

• compared with the reported carbomagnesiation reactions [124][125][126][127][128][129]. Hoveyda reported zirconium-catalyzed alkylmagnesiation reactions of styrene in 2001 by using primary or secondary alkyl tosylates as alkyl sources [130]. The reactions proceeded through zirconacyclopropane 4F as a key

New enzymatically polymerized copolymers from 4-tert-butylphenol and 4-ferrocenylphenol and their modification and inclusion complexes with β-cyclodextrin

• Adam Mondrzyk,
• Beate Mondrzik,
• Sabrina Gingter and
• Helmut Ritter

Beilstein J. Org. Chem. 2012, 8, 2118–2123, doi:10.3762/bjoc.8.238

• Kat.Nr. 202220602) as eluent and with a flow rate of 1 mL/min. The SEC system consists of a Gastorr BG 12 degasser (Schambeck), an Intelligent Pump AL-12 (FLOW), a S5200 sampler (Schambeck SFD) and a combination of columns (MZ Analysentechnik GmbH). The columns contain a styrene–divinylbenzene copolymer

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

• ) (0.75 mmol) and styrene (3a) (0.90 mmol) was carried out in common polar solvents, such as N,N-dimethylformamide, N,N-dimethylacetamide and dimethylsulfoxide, in the presence of different inorganic bases and NHC-Pd(II)-Im complex 1 (1.0 mol %) at 150 °C for 24 h. To our disappointment, almost no desired

• carrying out the reaction between chlorobenzene (2a) and styrene (3a) in the presence of NHC-Pd(II)-Im 1 using TBAB as the solvent at 140 °C (Table 1). As can be seen from Table 1, all reactions took place smoothly under air to give the desired coupling product 4a in low to excellent yields within 12 h in

• ). As can be seen from Table 2, most reactions proceeded well to give products 4 in good to high yields. For instance, in the first round, the reactions between various aryl chlorides 2 and styrene (3a) were examined (Table 2, entries 1–7). It seems that all of the activated and deactivated aryl

Palladium-catalyzed dual C–H or N–H functionalization of unfunctionalized indole derivatives with alkenes and arenes

• Gianluigi Broggini,
• Egle M. Beccalli,
• Andrea Fasana and
• Silvia Gazzola

Beilstein J. Org. Chem. 2012, 8, 1730–1746, doi:10.3762/bjoc.8.198

• alkenylation/carboxylation sequence was successfully performed by reaction of styrene compounds with 2-substituted indoles to give 3-benzylindoles bearing an ester group (Scheme 24). It should be pointed out that the presence of a functional group at the C-2 indolyl position is essential to obtain a

• satisfactory outcome of the reaction. Conversely, different substituents on the styrene substrates affected only the yield of the reaction. The intramolecular reaction has a stereospecific outcome, as demonstrated by the cyclization of the (Z) and (E)-deutero-indoles 46 (Scheme 25). In fact, (Z) and (E

C2-Alkylation of N-pyrimidylindole with vinylsilane via cobalt-catalyzed C–H bond activation

• Zhenhua Ding and
• Naohiko Yoshikai

Beilstein J. Org. Chem. 2012, 8, 1536–1542, doi:10.3762/bjoc.8.174

• -octene (2e) was even more sluggish, affording the alkylation product 3ae in only 9% yield (Scheme 3b). Styrene also reacted rather sluggishly to afford only a small amount of the alkylation product (3% as estimated by GC and GCMS), the regiochemistry (branched versus linear) of which has yet to be

Synthesis and evaluation of new guanidine-thiourea organocatalyst for the nitro-Michael reaction: Theoretical studies on mechanism and enantioselectivity

• Tatyana E. Shubina,
• Matthias Freund,
• Sebastian Schenker,
• Timothy Clark and
• Svetlana B. Tsogoeva

Beilstein J. Org. Chem. 2012, 8, 1485–1498, doi:10.3762/bjoc.8.168

• ), mediated by 7: Diethyl 2-(2-nitro-1-phenylethyl)malonate (15): A solution of trans-β-nitrostyrene (1.0 equiv), diethyl malonate (5.0 equiv) and 7 (0.2 equiv) in the desired solvent ([trans-β-nitro-styrene] = 0.1 M) is stirred at a certain temperature and for the appropriate time. The reaction is quenched

Photoreactions of cyclic sulfite esters: Evidence for diradical intermediates

• Rick C. White,
• Benny E. Arney Jr. and
• Heiko Ihmels

Beilstein J. Org. Chem. 2012, 8, 1208–1212, doi:10.3762/bjoc.8.134

• meso-hydrobenzoin sulfite undertaken about four decades ago stated that these compounds are also carbene precursors [16], in analogy to the results obtained with carbonate 1b. To provide further insight into the mechanism of the photoinduced cleavage of the cyclic sulfites, we examined the styrene

• glycol sulfite (8) and the hydrobenzoin sulfite (9); and we herein demonstrate that diradical intermediates are generated during the photoextrusion processes. Results and Discussion Styrene glycol sulfite 8 was prepared from thionyl chloride and styrene glycol in the presence of triethylamine [19]. The

• a Büchi 510K and are uncorrected. Phenyl benzyl ketone, diphenyl acetaldehyde, diphenylmethane, benzil, phenyl acetaldehyde, and bibenzyl were obtained commercially (Aldrich) and used as received. Styrene glycol sulfite was prepared by adding thionyl chloride (2.5 g, 21 mmol) in diethyl ether (50 mL

Alkoxide-induced ring opening of bicyclic 2-vinylcyclobutanones: A convenient synthesis of 2-vinyl-substituted 3-cycloalkene-1-carboxylic acid esters

• Xiufang Ji,
• Zhiming Li,
• Quanrui Wang and
• Andreas Goeke

Beilstein J. Org. Chem. 2012, 8, 650–657, doi:10.3762/bjoc.8.72

• 1a and the spiroheptadiene (1c) gave high yields of product 4 at 0 °C. However, the yields were moderate to low with cyclic mono olefin 1f or styrene (1g), even under reflux conditions. Mixtures of endo- and exo-isomers of compounds 4 were used in the subsequent ring-opening step without prior

Branching out at C-2 of septanosides. Synthesis of 2-deoxy-2-C-alkyl/aryl septanosides from a bromo-oxepine

• Supriya Dey and
• Narayanaswamy Jayaraman

Beilstein J. Org. Chem. 2012, 8, 522–527, doi:10.3762/bjoc.8.59

• substrate presenting two acrylates within the molecule, styrene, and α-methyl styrene (Scheme 1). Reactions with these substrates also afforded the diene products 4–7, in good yields. The anticipated two Heck coupling reactions with the substrate that presents two acrylates, could not be achieved, rather

• reactions afforded only the (E)-isomer. Interestingly, when the reaction was performed with α-methyl styrene, product 7, with an exocyclic double bond isomerization to a terminal double bond was observed. The appearance of two singlets at 5.30 and 5.14 ppm in the 1H NMR spectrum indicated the presence of

• Cs2CO3 (0.03 g, 0.11 mmol) and α-methyl styrene (0.01 mL, 0.09 mmol) in a sealed tube. The reaction mixture was stirred at 98 °C for 72 h, cooled, filtered, diluted with EtOAc (20 mL), washed with water (2 × 30 mL) and brine (2 × 10 mL), dried (Na2SO4) and concentrated in vacuo. The crude reaction

Synthesis and photooxidation of styrene copolymer bearing camphorquinone pendant groups

• Branislav Husár,
• Norbert Moszner and
• Ivan Lukáč

Beilstein J. Org. Chem. 2012, 8, 337–343, doi:10.3762/bjoc.8.37

• synthesized from (±)-10-camphorsulfonic acid either by a known seven-step synthetic route or by a novel, shorter five-step synthetic route. MCQ was copolymerized with styrene (S) and the photochemical behavior of the copolymer MCQ/S was compared with that of a formerly studied copolymer of styrene with

• monomers containing the benzil (BZ) moiety (another 1,2-dicarbonyl). Irradiation (λ > 380 nm) of aerated films of styrene copolymers with monomers containing the BZ moiety leads to the insertion of two oxygen atoms between the carbonyl groups of BZ and to the formation of benzoyl peroxide (BP) as pendant

• formed in irradiated films of styrene copolymers with pendant BZ groups leads to crosslinking, only small molecular-weight changes in irradiated MCQ/S were observed. Keywords: camphorquinone; 1,2-diketone; (±)-10-methacryloyloxycamphorquinone; photooxidation; polystyrene; Introduction Camphorquinone

A concise synthesis of 3-(1-alkenyl)isoindolin-1-ones and 5-(1-alkenyl)pyrrol-2-ones by the intermolecular coupling reactions of N-acyliminium ions with unactivated olefins

• Nianhong Lu,
• Lihong Wang,
• Zhanshan Li and
• Wei Zhang

Beilstein J. Org. Chem. 2012, 8, 192–200, doi:10.3762/bjoc.8.21

• -1-ones or 5-hydroxypyrrol-2-ones with unactivated olefins such as styrene (2a) (Scheme 1 and Scheme 2). Isoindolinones and pyrrolones are the core structures of numerous natural alkaloids [25][26][27] as well as many drug candidates [28][29][30]. Isoindolinones demonstrate a remarkably wide range of

• reduction of the parent phthalimide [35] and maleimide [36] derivatives. In order to explore the effects of the experimental conditions on the coupling reactions, the reaction of 1a with styrene (2a) was selected as a representative and carried out at room temperature under different conditions (Table 1

• 2.0 equiv BF3·OEt2 as catalyst and anhydrous DCM as solvent at room temperature was selected as the model for the general conditions for all of the other reactions. Under the selected conditions, the reactions of substrates 1a–c with different olefins, such as styrene (2a), α-methylstyrene (2b), 1,1

The application of a monolithic triphenylphosphine reagent for conducting Appel reactions in flow microreactors

• Kimberley A. Roper,
• Heiko Lange,
• Anastasios Polyzos,
• Malcolm B. Berry,
• Ian R. Baxendale and
• Steven V. Ley

Beilstein J. Org. Chem. 2011, 7, 1648–1655, doi:10.3762/bjoc.7.194

• phosphine monomer with a cross-linking component and a porogen [32][33]. A stock solution of the functionalised monomer (diphenyl(4-vinylphenyl)phosphine), cross-linking material (divinylbenzene and styrene) and porogen (1-dodecanol) was heated to 50 °C until a homogeneous solution was obtained. The

• hours in a Vapourtec R4 heater to give a white polymeric solid, which filled the column. It was noted that the addition of styrene as part of the cross-linking component was necessary to increase the active loading of the monolith during the reactions. Dibenzoyl peroxide was chosen as a radical

Continuous-flow enantioselective α-aminoxylation of aldehydes catalyzed by a polystyrene-immobilized hydroxyproline

• Xacobe C. Cambeiro,
• Rafael Martín-Rapún,
• Pedro O. Miranda,
• Sonia Sayalero,
• Esther Alza,
• Patricia Llanes and
• Miquel A. Pericàs

Beilstein J. Org. Chem. 2011, 7, 1486–1493, doi:10.3762/bjoc.7.172

• -linking agent and in the other case (1b) from a home-made Merrifield resin with 8% DVB (prepared by radical copolymerization of styrene, 4-chloromethylstyrene and DVB, under previously reported conditions [77][78][79]). It is well known that slightly cross-linked (1–2% DVB) polystyrene is microporous in

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

• related to cell toxicity in the presence of organic phases or emulsified product streams were avoided. A space-time yield of approximately 2.5 g L−1 day−1 was achieved. Another method to surmount substrate toxicity was used by Gross et al. in the oxidation of styrene (73) to (S)-styrene oxide (74) in a

• ]. Continuous epoxidation of 1,7-octadiene (70) to (R)-7-epoxyoctene (72) by a strain of Pseudomonas oleovorans in a closed-gas-loop bioreactor (CCGLB). R: Reductase; Fe: Rubredoxin [51]. Oxidation of styrene (73) to (S)-styrene oxide (74) in a continuously operated biofilm tube reactor containing cells of

Multistep flow synthesis of vinyl azides and their use in the copper-catalyzed Huisgen-type cycloaddition under inductive-heating conditions

• Lukas Kupracz,
• Jan Hartwig,
• Jens Wegner,
• Sascha Ceylan and
• Andreas Kirschning

Beilstein J. Org. Chem. 2011, 7, 1441–1448, doi:10.3762/bjoc.7.168

• from light with aluminum foil. The reactor (void volume: 4.5 mL) was connected to the pump and, at the outlet side, to a collection flask. The system was first flushed with dry CH2Cl2 (8 mL, 0.5 mL/min). Then, a solution of styrene (2a) (364 mg, 3.5 mmol) in dry CH2Cl2 (17.5 mL) was pumped through the

• ; theoretical loading = 1.15 mmol/g) in dry CH2Cl2 (5 mL), were telescoped and protected from light with aluminum foil. The system was connected to the pump and, at the outlet side, to a collection flask. After priming with CH2Cl2 (10 ml), a solution of styrene (2a) (364 mg, 3.5 mmol) in dry CH2Cl2 (17.5 mL

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

• ) BINAPHOS was employed to form the corresponding Rh catalyst. For volatile alkenes, a direct flow system was used, while for nonvolatile substrates scCO2 was used as the carrier phase. Thus, for styrene a ca. 50% conversion was achieved with an 80:20 b/l ratio and 85% ee (Scheme 5). b) Catalysts immobilized

• phase state of the reaction mixture. Thus, those results confirmed that it is possible to control the alkylation selectivity by a simple tuning of the properties of the supercritical fluid. A second example involves the hydrovinylation of styrene using the Wilke’s catalyst immobilized on an IL (Scheme 6

• styrene (Scheme 7). Similar approaches allow the preparation of polymers containing PyBOX subunits, from which the corresponding Rh complexes can be formed and studied for the same reaction [75]. The preparation of this kind of catalyst in the form of monolithic polymers inside stainless steel columns is

Evaluation of a commercial packed bed flow hydrogenator for reaction screening, optimization, and synthesis

• Marian C. Bryan,
• David Wernick,
• Christopher D. Hein,
• James V. Petersen,
• John W. Eschelbach and
• Elizabeth M. Doherty

Beilstein J. Org. Chem. 2011, 7, 1141–1149, doi:10.3762/bjoc.7.132

• the ThalesNano H-Cube®, a commercial packed bed flow hydrogenator, was evaluated in the context of small scale reaction screening and optimization. A model reaction, the reduction of styrene to ethylbenzene through a 10% Pd/C catalyst bed, was used to examine performance at various pressure settings

• H-Cube® and the effect of that dispersion on the reaction outcome [15]. As a result of that study, we generated a predictive correlation between non-steady state and continuous flow scale-up conditions for simple reductions. In this report, using the reduction of styrene to ethylbenzene over 10% Pd

• the controlled mode introduces less hydrogen into the reactant stream than in the full H2 mode setting. As an indirect measure of the availability of hydrogen during the course of a reaction in the controlled mode setting, the reduction of styrene to ethylbenzene was monitored by in-line UV using the

When gold can do what iodine cannot do: A critical comparison

• Sara Hummel and
• Stefan F. Kirsch

Beilstein J. Org. Chem. 2011, 7, 847–859, doi:10.3762/bjoc.7.97

• , gold-catalyzed domino processes with 1,6-enynes have been shown to proceed in high yields to provide access to carbon skeletons that are not easily synthesized by other approaches. A striking example of the latter is outlined in Scheme 19 [115]. The 1,6-enyne 68 reacts with substituted styrene 69 in

High chemoselectivity in the phenol synthesis

• Matthias Rudolph,
• Melissa Q. McCreery,
• Wolfgang Frey and
• A. Stephen K. Hashmi

Beilstein J. Org. Chem. 2011, 7, 794–801, doi:10.3762/bjoc.7.90

• Intermolecular olefinic trapping reagents We started with the simplest experiments, namely the intermolecular trapping of the gold carbenoid intermediates. When 3 was reacted in the presence of an activated olefin, such as norbornene or styrene, phenol 4 was formed exclusively in essentially quantitative yield

• carbonyl group. Reaction with both tosylamide 3 and ether 6 always delivered the phenolic products 4 or 7, respectively (Scheme 3). The same result was obtained when PtCl2 was used as the catalyst for the conversion of 3. Intramolecular olefinic trapping reagents The next step was to offer the styrene unit

• in an intramolecular manner. Substrate 8 could potentially undergo three different modes of reaction (Scheme 4). After the initial step, the intermediate E would be produced (analogous to A). Cyclopropanation of the styrene subunit by the cyclopropyl carbenoid would deliver 9. If E rearranged to the

Continuous flow hydrogenation using polysilane-supported palladium/alumina hybrid catalysts

• Hidekazu Oyamada,
• Takeshi Naito and
• Shū Kobayashi

Beilstein J. Org. Chem. 2011, 7, 735–739, doi:10.3762/bjoc.7.83

• cap. Line: A sus tube (outside diameter: 1/16 inch) was used for line A, a PEEK tube (outside diameter: 1/16 inch) was used for line B and a Teflon tube (outside diameter: 3 mm) was used for line C. Typical procedure for hydrogenation reactions (Table 1, entry 1): Styrene was fed into the column using

• the HPLC pump, and H2 gas was introduced into the column using the mass flow controller. The system was left to stabilize for 30 min, and the product was then sampled over 1.5 h. The sample was analyzed by 1H NMR, and the complete conversion of styrene to ethyl benzene was confirmed. 1H NMR (500 MHz

When cyclopropenes meet gold catalysts

• Frédéric Miege,
• Christophe Meyer and
• Janine Cossy

Beilstein J. Org. Chem. 2011, 7, 717–734, doi:10.3762/bjoc.7.82

• intermediate. Thus, when 3-methyl-3-nonylcyclopropene (8) was treated with a catalytic amount of [(Ph3P)AuNTf2] in the presence of excess styrene, the alkenyl cyclopropane 44, resulting from intermolecular cyclopropanation triggered by the gold carbene 43, was isolated in 72% yield as a 6:1 mixture of cis

• ethyl diazoacetate on bulk gold powder were also studied, but mixtures of self- and cross-coupling products were invariably obtained with negligible selectivity. Interestingly, the authors investigated the intermolecular cyclopropanation of styrene by the surface bound gold carbene generated from

• cyclopropene 1. Though a large excess of styrene (100 equiv) was used, triene 45 resulting from the self-coupling of 1 still predominated, and the cyclopropanation product 46 was isolated in low yield (19%) as a single trans diastereomer (Scheme 21) [23]. In their investigations on the bonding model for gold(I

Synthesis, reactivity and biological activity of 5-alkoxymethyluracil analogues

• Lucie Brulikova and
• Jan Hlavac

Beilstein J. Org. Chem. 2011, 7, 678–698, doi:10.3762/bjoc.7.80

• styrene to afford nucleoside 147. The oxidation of alkene function in 147 with OsO4 led to a mixture of diastereomers of vicinal diols 148. For the introduction of the oligodeoxynucleotide 146, the dihydroxynucleoside 147 was converted to the corresponding phosphoramidite. This was carried out as follows

Synthesis of Ru alkylidene complexes

• Renat Kadyrov and
• Anna Rosiak

Beilstein J. Org. Chem. 2011, 7, 104–110, doi:10.3762/bjoc.7.14

• ) [13] internal rotation barriers of styrene, 2-vinylthiophene (Ea = 4.8 kcal/mol) [14] and is comparable with rotation barrier of the aryl ring in chromium carbene complexes (ΔG≠298K = 13.0–16.2 kcal/mol) [15]. Experimental Routine, 2D-correlation spectra (1H,1H-COSY) and SELNOE experiments were