(Bio)isosteres of ortho- and meta-substituted benzenes

• H. Erik Diepers and
• Johannes C. L. Walker

Beilstein J. Org. Chem. 2024, 20, 859–890, doi:10.3762/bjoc.20.78

• in moderate to good yields, employing 2,7-dimethoxythioxanthone (2,2’-OMeTX) as a triplet sensitizer for BCB excitation (Scheme 3A) [38]. Starting from BCB 24, alkenes including styrene derivatives, enol ethers, and vinyl boronates could be incorporated to give 1,2-BCHs (±)-25a–d. Brown and co

Advancements in hydrochlorination of alkenes

• Daniel S. Müller

Beilstein J. Org. Chem. 2024, 20, 787–814, doi:10.3762/bjoc.20.72

• through a solution of the alkene in diethyl ether at 0 °C or rt (Scheme 3B and 3C) [36]. Despite its effective reaction with styrene (3), the reaction displayed sluggish reactivity with 1-propenylbenzene (5). It is noteworthy, that the following HCl solutions are commercially available: 4.0 M in dioxane

• alkenes remains a commonly employed approach, yielding high yields for styrene derivatives (Scheme 4) [41][42][43]. The example by Theato is remarkable (Scheme 4A), who used HCl (gas) bubbled into neat alkene 13 for 5 hours, and obtained a relatively high yield of the monohydrochlorinated product 14 after

• broad generality and tolerates various sensitive functional groups, including aldehyde 45 and nitrile 46. However, electron-poor styrene, resulting in chloride 40, or terminal and 1,2-disubstituted alkenes forming chlorides 41–46 and cyclooctyl chloride (26) necessitated harsher reaction conditions. As

SOMOphilic alkyne vs radical-polar crossover approaches: The full story of the azido-alkynylation of alkenes

• Julien Borrel and
• Jerome Waser

Beilstein J. Org. Chem. 2024, 20, 701–713, doi:10.3762/bjoc.20.64

• as raw data in our previous work [45]. Results and Discussion SOMOphilic alkynes We started to investigate the azido-alkynylation of styrene (1a) using EBX reagent 2 as SOMOphilic alkyne (Table 1). Tosyl-azidobenziodazolone (Ts-ABZ, 3), previously developed by our group [17], was selected as an azide

• source. Upon light irradiation, it can release an azide radical by homolysis of the I−N3 bond [46]. We were pleased to see that irradiation of a mixture of styrene (1a), Ph-EBX (2) and Ts-ABZ (3) afforded 17% isolated yield of the desired homopropargylic azide 4a (Table 1, entry 1). Heating the reaction

• no impact on the reaction (Table 1, entry 12), the presence of 1.5 equivalents of HFIP slightly improved the yield (Table 1, entry 13). Increasing the amount of styrene in the reaction had no impact (Table 1, entry 14), highlighting that the issue might come from an inefficient trapping of the C

Palladium-catalyzed three-component radical-polar crossover carboamination of 1,3-dienes or allenes with diazo esters and amines

• Geng-Xin Liu,
• Xiao-Ting Jie,
• Ge-Jun Niu,
• Li-Sheng Yang,
• Xing-Lin Li,
• Jian Luo and
• Wen-Hao Hu

Beilstein J. Org. Chem. 2024, 20, 661–671, doi:10.3762/bjoc.20.59

• (TEMPO) and the corresponding radical-trapping product A could be confirmed by HRMS of both reaction mixtures, unambiguously supporting radical mechanisms (Scheme 4a). The reaction with styrene was conducted under standard conditions, but no product X could be detected, indicating the cationic

Enhanced reactivity of Li⁺@C₆₀ toward thermal [2 + 2] cycloaddition by encapsulated Li⁺ Lewis acid

• Hiroshi Ueno,
• Yu Yamazaki,
• Hiroshi Okada,
• Fuminori Misaizu,
• Ken Kokubo and
• Hidehiro Sakurai

Beilstein J. Org. Chem. 2024, 20, 653–660, doi:10.3762/bjoc.20.58

• derivatization of this novel material. In this study, we report the synthesis of Li+@C60 derivatives via the thermal [2 + 2] cycloaddition reaction of styrene derivatives, achieving significantly higher yields of monofunctionalized Li+@C60 compared to previously reported reactions. Furthermore, by combining

• range of unsaturated substrates having a relatively lower HOMO level. With the previously uncovered reactivity of Li+@C60 in hand, we synthesized Li+@C60 derivatives in this study through the thermal [2 + 2] cycloaddition of styrene derivatives, which do not react with empty C60 through the same

• of N,N,N',N'-tetraethylethynediamine and 1-morpholino-1-cyclopentene with empty C60 has been reported [17][23], while electron-rich styrene derivatives 1 and 2 can react with empty C60 only through a photoinduced SET pathway [19][22]. From these results, the energy gap between the HOMO of the alkene

Mechanisms for radical reactions initiating from N-hydroxyphthalimide esters

• Carlos R. Azpilcueta-Nicolas and
• Jean-Philip Lumb

Beilstein J. Org. Chem. 2024, 20, 346–378, doi:10.3762/bjoc.20.35

• . Radical intermediate 9 formed upon fragmentation of 25, adds to the styrene acceptor forming radical 26. Finally, a radical-polar crossover event between 26 and the IrIV complex regenerates the IrIII ground state while delivering cation 27 that is then trapped by the oxygen-nucleophile to form the

• oxyalkylation product 28. Li and co-workers described the activation of NHPI esters towards SET using a Lewis acid catalyst, allowing for the functionalization of styrene radical acceptors with nucleophiles that do not necessarily engage in hydrogen-bonding interactions, such as electron-rich (hetero)arenes [47

• the phthalimide moiety (Scheme 7B). Thus, the excited state reductant *IrIII reduces the activated substrate 29 to form the stabilized radical anion 30. Fragmentation into radical 9, followed by radical addition to styrene gives benzyl radical intermediate 26. Turn-over of the catalytic cycle through

Photochromic derivatives of indigo: historical overview of development, challenges and applications

• Gökhan Kaplan,
• Zeynel Seferoğlu and
• Daria V. Berdnikova

Beilstein J. Org. Chem. 2024, 20, 228–242, doi:10.3762/bjoc.20.23

• using heme-containing oxygenases (cytochrome P450 monooxygenases, styrene/indole monooxygenases, flavin-containing monooxygenases, Baeyer–Villiger monooxygenases, etc.) or non-heme iron oxygenases (naphthalene dioxygenases, multicomponent phenol hydroxylases) [5][6][7][8]. The synthetic approaches

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

• decades [28]. 1.3.1 Deactivation by reversible coupling: In 1982, Otsu and Yoshida [29] successfully polymerized styrene and MMA using dithiocarbamate compounds, and in 1986, Solomon et al. [30] published a patent entitled "Polymerization Processes and Polymers Produced Thereby", which led to the

• acrylates, under milder conditions [37][38][39]. Grimaldi et al. [40] achieved NMP of styrene and n-butyl acrylate using SG1-type nitroxide radical (N-tert-butyl-N-(1-diethylphosphono-2,2-dimethylpropyl)nitroxide). Compared with TEMPO, SG1 was considered that it initiated the truly “living”/controlled

N-Sulfenylsuccinimide/phthalimide: an alternative sulfenylating reagent in organic transformations

• Fatemeh Doraghi,
• Seyedeh Pegah Aledavoud,
• Mehdi Ghanbarlou,
• Bagher Larijani and
• Mohammad Mahdavi

Beilstein J. Org. Chem. 2023, 19, 1471–1502, doi:10.3762/bjoc.19.106

• presence of TMSOTf. Catalyst-free sulfenylation by N-(sulfenyl)succinimides/phthalimides In 2015, oxysulfenylation of styrene derivatives 9 utilizing 1-(arylthio)pyrrolidine-2,5-diones 1 and alkyl/benzyl alcohols 86 toward β-alkoxy sulfides was developed by Fu et al. (Scheme 65) [95]. In this metal-free

Exploring the role of halogen bonding in iodonium ylides: insights into unexpected reactivity and reaction control

• Carlee A. Montgomery and
• Graham K. Murphy

Beilstein J. Org. Chem. 2023, 19, 1171–1190, doi:10.3762/bjoc.19.86

• population analysis revealed that 0.26 e of electron density was transferred to iodine, resulting in a 1,2-diradical (41*, Figure 9). In their mechanistic proposal, they presumed that this excited species would not have been sufficiently long-lived to encounter the styrene (41*→43*). Instead, they invoked an

• -substituted iodoarene-derived iodonium ylides for improved solubility and stability [5][6][141]. ortho-Iodoanisole-derived ylide 39 was subject to a rhodium-catalyzed cyclopropanation reaction with styrene, and the results were compared with Charette’s 2009 work on 31 (Scheme 15) [142]. While both ylides were

Photoredox catalysis harvesting multiple photon or electrochemical energies

• Mattia Lepori,
• Simon Schmid and
• Joshua P. Barham

Beilstein J. Org. Chem. 2023, 19, 1055–1145, doi:10.3762/bjoc.19.81

Light-responsive rotaxane-based materials: inducing motion in the solid state

• Adrian Saura-Sanmartin

Beilstein J. Org. Chem. 2023, 19, 873–880, doi:10.3762/bjoc.19.64

• shows the styrene-based derivatives coordinated in an antiparallel manner through the carboxylic acid group placed at the end of each thread, thus avoiding the dethreading process. Two identical intertwined scaffolds were formed differing in the photoactivities due to different conformations. In the

Pyridine C(sp²)–H bond functionalization under transition-metal and rare earth metal catalysis

• Haritha Sindhe,
• Malladi Mounika Reddy,
• Karthikeyan Rajkumar,
• Akshay Kamble,
• Amardeep Singh,
• Anand Kumar and
• Satyasheel Sharma

Beilstein J. Org. Chem. 2023, 19, 820–863, doi:10.3762/bjoc.19.62

• on subsequent deprotonation gives the branched alkylated product 4. Whereas, in case of styrene 3 a 1,2-insertion takes place possibly due to the formation of the stable benzallylic species 8, which on deprotonation gives the linear alkylated product 5. The C–H activation/C–C cross-coupling reaction

• migratory insertion of the alkene into the metal–C bond of 23 gives the intermediate 24a on reaction with styrene 18 and intermediate 24b in the presence of alkene 20. The intermediates 24a and 24b then undergo further hydrolysis to give the desired linear products 19 and branched products 21, respectively

• NHC aryl part with trans-styrene was highly important for the reaction to proceed and for the enantiocontrolled formation of the products. Alkenylation The C–H alkenylation is another important C–C bond-forming reaction. Olefinated organic molecules like vinylarenes play a significant role as key

Strategies in the synthesis of dibenzo[b,f]heteropines

• David I. H. Maier,
• Barend C. B. Bezuidenhoudt and
• Charlene Marais

Beilstein J. Org. Chem. 2023, 19, 700–718, doi:10.3762/bjoc.19.51

• used to synthesise dibenzo[b,f]thiapines 1c and dibenzo[b,f]oxepines 1b in three steps through a styrene (95 and 96) intermediate (Scheme 19). While the reported conversion was excellent, the yield was low due to moderate selectivity, resulting in a mixture of 7-endo (1c and 1b) and 6-exo (97 and 98

C3-Alkylation of furfural derivatives by continuous flow homogeneous catalysis

• Grédy Kiala Kinkutu,
• Catherine Louis,
• Myriam Roy,
• Juliette Blanchard and
• Julie Oble

Beilstein J. Org. Chem. 2023, 19, 582–592, doi:10.3762/bjoc.19.43

• with good productivity. Alkenes without silicon in the vinyl position seemed much less reactive, such as a vinylacetal, a hindered olefin (3,3-dimethyl-1-butene), or styrene. In these cases, functionalized furfurals were not isolated. In contrast, norbornene, which has a more reactive double bond due

Access to cyclopropanes with geminal trifluoromethyl and difluoromethylphosphonate groups

• Ita Hajdin,
• Romana Pajkert,
• Mira Keßler,
• Jianlin Han,
• Haibo Mei and
• Gerd-Volker Röschenthaler

Beilstein J. Org. Chem. 2023, 19, 541–549, doi:10.3762/bjoc.19.39

• confirm the lack of selectivity during the cyclopropanation process with terminal alkenes, the reaction mechanism between the diazo reagent 5 and styrene as a model substrate in the presence of CuI catalyst was investigated by density functional theory (DFT) calculations (Table 2). In the first step, CuI

• adds to styrene to the carbon atom in 2-position of the ethenyl group. At this point, four different orientations of the phenyl group are conceivable (Scheme 6 and Scheme 7, TS2_1 to TS2_4). After an early transition state with hardly any activation barrier, the addition of styrene to Int2 proceeds in

• mmol), CuI (1 mol %), dry toluene, 111 °C, Ar atmosphere. aYields refer to isolated products; bdr ratio determined by 19F NMR spectroscopy. Addition of CuI to the diazo compound 5. Possible addition of styrene to Int2 yielding Int4_1 and Int4_2 through Int3_1 and Int3_2. Possible addition of styrene to

Combretastatins D series and analogues: from isolation, synthetic challenges and biological activities

• Jorge de Lima Neto and
• Paulo Henrique Menezes

Beilstein J. Org. Chem. 2023, 19, 399–427, doi:10.3762/bjoc.19.31

• the authors consisted in the ring closure through a metathesis reaction using the Grubbs catalyst [52][53]. The required compound 99 was prepared by converting compound 16 into the styrene 98 via a Wittig reaction followed by a transesterification to yield the desired allylic ester. Several reaction

Strategies to access the [5-8] bicyclic core encountered in the sesquiterpene, diterpene and sesterterpene series

• Cécile Alleman,
• Charlène Gadais,
• Laurent Legentil and
• François-Hugues Porée

Beilstein J. Org. Chem. 2023, 19, 245–281, doi:10.3762/bjoc.19.23

• from 2 equivalents of 99 and the cross metathesis adduct resulting from 99 and a styrene unit coming from the catalyst. In addition, the corresponding RCM on the alkene analogue of 99 did not proceed either with G-II or Schrock catalysts, showcasing the substrate sensitivity of this reaction. 1.3

Nostochopcerol, a new antibacterial monoacylglycerol from the edible cyanobacterium Nostochopsis lobatus

• Naoya Oku,
• Saki Hayashi,
• Yuji Yamaguchi,
• Hiroyuki Takenaka and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2023, 19, 133–138, doi:10.3762/bjoc.19.13

• responsible constituent, though prone to diffuse during chromatography, was purified with the guidance of antibacterial activity on ODS and Sephadex LH-20 and by reversed-phase HPLC on ODS and styrene-divinylbenzene copolymer to yield 0.7 mg of compound 1 from 113.3 mg of the solvent partition fraction. The

• ) to see the separation of activity at the top two and slow-eluting fractions. The top fraction was purified by repeated HPLC first on an ODS column (Cosmosil AR-II 1 × 25 cm) and second on a styrene-divinylbenzene polymer column (Hamilton PRP-1 1 × 25 cm) both eluted with MeCN/50 mM NaClO4 75:25 to

1,4-Dithianes: attractive C2-building blocks for the synthesis of complex molecular architectures

• Bram Ryckaert,
• Ellen Demeyere,
• Frederick Degroote,
• Hilde Janssens and
• Johan M. Winne

Beilstein J. Org. Chem. 2023, 19, 115–132, doi:10.3762/bjoc.19.12

• dependence [95]. On the other hand, simple benzyl cations can undergo more controlled (3 + 2) annulations, as is illustrated by the long-known Friedel–Crafts-type acid-catalyzed cascade reaction of styrene leading to the cyclic styrene dimer 86 (Scheme 13c) [96][97]. This (3 + 2) cycloaddition reactivity of

• dienes very cleanly give the cyclopentannulated products in good yields, and with excellent stereo- and regioselectivity (Scheme 14c), as demonstrated by the reaction of abietic acid (93), affording 94 as a single regio- and stereoisomer. Similarly, a wide range of styrene substrates smoothly underwent

• the (3 + 2) cycloaddition pathway under simple acid-promoted conditions, without notable problems of styrene oligomerization or homodimerization. The method allowed a short racemic total synthesis of the sesquiterpenoid cuparene (±-98, Scheme 14d), wherein the synthetic challenge of the contiguous

Redox-active molecules as organocatalysts for selective oxidative transformations – an unperceived organocatalysis field

• Elena R. Lopat’eva,
• Igor B. Krylov,
• Dmitry A. Lapshin and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2022, 18, 1672–1695, doi:10.3762/bjoc.18.179

• following example of styrene diamination by a chiral aryl iodide, the higher efficiency of the proposed catalyst compared to simpler aryl iodides was attributed to the additional stabilization of the I(III) intermediate by chelation via n–σ* interactions and hydrogen bonding [147] (Scheme 33). The

Synthetic strategies for the preparation of γ-phostams: 1,2-azaphospholidine 2-oxides and 1,2-azaphospholine 2-oxides

• Jiaxi Xu

Beilstein J. Org. Chem. 2022, 18, 889–915, doi:10.3762/bjoc.18.90

• with the generated styrene in the reaction mixture (Scheme 18) [42]. One year later, the same group investigated the influence of the double bond geometry and the substitution pattern on the alkene. The results indicated that the double bond geometry plays a moderate role, while the bulkiness of the R

Cathodic generation of reactive (phenylthio)difluoromethyl species and its reactions: mechanistic aspects and synthetic applications

• Sadanobu Iwase,
• Shinsuke Inagi and
• Toshio Fuchigami

Beilstein J. Org. Chem. 2022, 18, 872–880, doi:10.3762/bjoc.18.88

• radicals such as n-perfluoropropyl radical have high reactivity to electron-rich olefins such as α-methylstyrene and styrene [26]. In fact, our cathodically generated reactive species also reacted with α-methylstyrene. However, electron-rich dihydrofuran did not provide any radical adduct at all (Table 1

• . The generated radicals undergo addition to olefins and acetylenes [5][33]. Pohmakotr et al. and Yoshida et al. reported that the reaction of PhSCF2Br and PhCF2Cl with SmI2 generated PhSCF2 and PhCF2 radicals, which were trapped with styrene [5][34][35]. Therefore, we carried out the reaction of

• compound 1 with SmI2 in the absence and presence of α-methylstyrene, which is more electron-rich compared to styrene. The results are summarized in Table 3. As shown in Table 3, even when two equivalents of SmI2 were used in the absence of α-methylstyrene, the conversion of compound 1 was low and a large

Heteroleptic metallosupramolecular aggregates/complexation for supramolecular catalysis

• Prodip Howlader and
• Michael Schmittel

Beilstein J. Org. Chem. 2022, 18, 597–630, doi:10.3762/bjoc.18.62

• hydride species 49 that is well known for hydroformylation reactions [77]. Incorporation of the monoligated catalyst into the confined cavity of the capsule showed very good catalytic activity towards the hydroformylation of styrene (50, Figure 11) with a high stereoselectivity (65% ee) at 32% conversion

Shift of the reaction equilibrium at high pressure in the continuous synthesis of neuraminic acid

• Jannis A. Reich,
• Miriam Aßmann,
• Kristin Hölting,
• Paul Bubenheim,
• Jürgen Kuballa and
• Andreas Liese

Beilstein J. Org. Chem. 2022, 18, 567–579, doi:10.3762/bjoc.18.59

• of 80 mgenzyme/gcarrier was achieved. Two carriers revealed lower yields with enzyme loadings of 30 and 40 mgenzyme/gcarrier (epoxy methacrylate, polymethacrylic DVB). The aldolase revealed the highest loadings with 80 mgenzyme/gcarrier for the amino methacrylate und macroporous styrene carrier. The

• highest activities immobilized on amino methacrylate with about 25 U/gcarrier. Compared to this, the results of all other specific activities were lower with less than 10 U/gcarrier. Here the epoxy butyl methacrylate and the macroporous styrene carrier reveal slightly more activity with more than 5 U

• methacrylate, and macroporous styrene (Figure 6). All carriers show high suitability for repeated application with the highest loss of activity (35%) for the epoxy butyl methacrylate carrier and macroporous styrene carrier (25%). Both enzymes showed a suitable reusability in the recycling study. Due to the