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

• produced to initiate the polymerization. By formation of radicals, the polymerization of C=C functions such as (meth)acrylates or styrene can be initiated. With cations or acids as initiating species, epoxy monomers can be polymerized. Both types of polymerization are widely used both in academic and

A tutorial review of stereoretentive olefin metathesis based on ruthenium dithiolate catalysts

• Daniel S. Müller,
• Olivier Baslé and
• Marc Mauduit

Beilstein J. Org. Chem. 2018, 14, 2999–3010, doi:10.3762/bjoc.14.279

• norbornadiene was also investigated by Hoveyda [16]. A highly syndiotactic polymer was obtained by fine tuning of the steric and electronic characteristics of the catalyst (not depicted in this review) [16]. ROCM reactions of norbornene (1) with styrene (5) could be carried out with only one mole percent of

• styrene 32 the protonation and loss of the catechothiolate ligand by Brønsted acid 34 is a faster process leading to catalyst degradation. It should be noted that stereoretentive CM and RCM with (E)-2-butene (E-25) as capping reagent were also reported, however, these reactions required a significantly

Olefin metathesis catalysts embedded in β-barrel proteins: creating artificial metalloproteins for olefin metathesis

• Daniel F. Sauer,
• Johannes Schiffels,
• Takashi Hayashi,
• Ulrich Schwaneberg and
• Jun Okuda

Beilstein J. Org. Chem. 2018, 14, 2861–2871, doi:10.3762/bjoc.14.265

• modification of the first coordination sphere by adding an N-heterocyclic carbene (NHC) ligand and a chelating styrene to the so-called Grubbs 1st generation catalyst, the relatively air- and moisture-stable Grubbs–Hoveyda type (GH-type) catalysts were obtained [7]. These catalysts do not only show stability

• mutant formed the starting variant for the next iterative round. As screening substrate, the pre-fluorescent styrene derivative 3 was used. Following RCM, the fluorescent molecule umbelliferone (4) was generated. In total, five rounds of directed evolution were performed, yielding the mutant

• [52][53], and hydrogen evolution [54]. Further, Lewis et al. employed the NB scaffold for epoxidation of styrene and other olefins [55]. In all studies, the catalyst incorporated into the NB scaffold showed increased activity as compared to the protein-free catalyst under similar conditions

Synthesis of unnatural α-amino esters using ethyl nitroacetate and condensation or cycloaddition reactions

• Glwadys Gagnot,
• Vincent Hervin,
• Eloi P. Coutant,
• Sarah Desmons,
• Racha Baatallah,
• Victor Monnot and
• Yves L. Janin

Beilstein J. Org. Chem. 2018, 14, 2846–2852, doi:10.3762/bjoc.14.263

• [21] between two equivalents of ethyl nitroacetate (4) and styrene (15), gave the isoxazoline 16 in a 72% yield as a latent α-amino ester [22][23][24]. From this compound, a reductive cleavage of the isoxazoline ring was initiated using palladium over charcoal and a large excess of ammonium formate in

An overview on recent advances in the synthesis of sulfonated organic materials, sulfonated silica materials, and sulfonated carbon materials and their catalytic applications in chemical processes

• Hashem Sharghi,
• Pezhman Shiri and
• Mahdi Aberi

Beilstein J. Org. Chem. 2018, 14, 2745–2770, doi:10.3762/bjoc.14.253

• ionic imidazole on SBA-15 85 in deionized water and stirred at 25 °C for 12 h (Scheme 15). The HPW-based ionic liquid immobilized on mesoporous silica SBA-15 86 displayed excellent utility and reusability for alkylation of o-xylene (87) with styrene (88). Although the homogeneous HPW displayed very high

• catalytic activity for the alkylation of o-xylene with styrene, it cannot be separated from the reaction mixture. The SBA-15 support itself exhibited no activity for the reaction, but 30% HPW-PMIMPS-SBA-15 material produced the highest yield and showed good selectivity. Decreasing and increasing in the

• [2,1-b]phthalazinetriones and triazolo[1,2-a]indazoletriones. The synthetic route for heteropolyanion-based ionic liquids immobilized on mesoporous silica SBA-15 and its catalytic activity for the alkylation of o-xylene with styrene. Some mechanism aspects of SSA catalyst for the protection of amine

Synergistic approach to polycycles through Suzuki–Miyaura cross coupling and metathesis as key steps

• Sambasivarao Kotha,
• Milind Meshram and
• Chandravathi Chakkapalli

Beilstein J. Org. Chem. 2018, 14, 2468–2481, doi:10.3762/bjoc.14.223

• CM by using Mo complex 6. In this regard, they assembled stilbene derivative 85 as an antitumor agent by a two-step strategy that involve catalytic CM and SM coupling. To this end, the Z-selective CM of a styrene derivative (e.g., 81) with vinyl-B(pin) 82 was realized in the presence of Mo complex 6

Cobalt- and rhodium-catalyzed carboxylation using carbon dioxide as the C1 source

• Tetsuaki Fujihara and
• Yasushi Tsuji

Beilstein J. Org. Chem. 2018, 14, 2435–2460, doi:10.3762/bjoc.14.221

• reductant, carboxyzincation and the four-component coupling reaction between alkyne, acrylates, CO2, and zinc occur efficiently. Rh complexes also catalyze the carboxylation of arylboronic esters, C(sp2)–H carboxylation of aromatic compounds, and hydrocarboxylation of styrene derivatives. The Rh-catalyzed

• hydrocarboxylation of styrene derivatives has been achieved. Furthermore, the formation of pyrones from diynes and CO2 can be effectively catalyzed by Rh complexes. Review Cobalt catalysts Carboxylation of propargyl acetates Allyl and propargyl electrophiles, such as halides and esters, are well known as efficient

• using alkynes [63][64][65][66], alkenes [67][68], allenes [69][70][71] and 1,3-dienes [72][73] have been reported. In this regard, Mikami et al. reported the Rh-catalyzed hydrocarboxylation of styrene derivatives depicted in Scheme 33 [74]. The desired reaction proceeded using [RhCl(cod)]2 as a catalyst

Hydroarylations by cobalt-catalyzed C–H activation

• Rajagopal Santhoshkumar and
• Chien-Hong Cheng

Beilstein J. Org. Chem. 2018, 14, 2266–2288, doi:10.3762/bjoc.14.202

• (Scheme 20b) [66]. Moreover, the Co-catalyzed hydroarylation of styrene with ketimine or aldimine proceeded without Grignard reagent using Mg metal as the reductant [67]. Recently, N–H imines 9d were also employed for the hydroarylation reaction with styrenes, giving a branched-selective hydroarylation

• styrenes, while alkylalkenes resulted in linear-selective products 35b. Similarly, quinolines 34a also underwent hydroarylation reaction with styrene to give C4-selective alkylated products 36 in good regioselectivity (Scheme 24b) [76]. 2.2 Co(III)-catalyzed hydroarylation of alkenes In 2013, Kanai

• selectivity in some cases. Switchable regioselective hydroarylation of styrene using low-valent cobalt catalyst and Co(III)-catalyzed hydroarylation of alkylalkenes with indoles are remarkable examples in this manner. A wide range of C−H bonds has been successfully added to alkynes, alkenes, imines etc. to

A general and atom-efficient continuous-flow approach to prepare amines, amides and imines via reactive N-chloramines

• Katherine E. Jolley,
• Michael R. Chapman and
• A. John Blacker

Beilstein J. Org. Chem. 2018, 14, 2220–2228, doi:10.3762/bjoc.14.196

• further reactions. Reaction of N-chloramine with alkene Initially our study tested the reaction of N-chloromorpholine (16) to styrene (13) varying Cu catalyst loading and a range of temperatures. The anti-Markovnikov addition product was observed with 10% CuI catalyst loading, at ambient temperature

• 11 or 12 into a stream of toluene containing styrene (13) enabled the continuous production of alkylated amine products 14 and 15 (Table 2, entries 7 and 8, respectively). In each case the tres was comparable with batch (reaction of 11 = 75 minutes, 12 = 60 minutes), with steady-state conversions or

• in situ generated imines. Continuous N-chloramine formation. Batch vs flow study of reaction of N-chloramine with styrene. Batch vs flow study of reaction of N-chloramine with an aldehyde. Batch optimization study of the dehydrochlorination of N-chloramines. Batch vs flow study of the

Hypervalent iodine compounds for anti-Markovnikov-type iodo-oxyimidation of vinylarenes

• Igor B. Krylov,
• Stanislav A. Paveliev,
• Mikhail A. Syroeshkin,
• Alexander A. Korlyukov,
• Pavel V. Dorovatovskii,
• Yan V. Zubavichus,
• Gennady I. Nikishin and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2018, 14, 2146–2155, doi:10.3762/bjoc.14.188

• formation of C–I and C–O bonds, which implies the radical pathway of the reaction. The iodo-oxyimidation of styrenes was studied in the model reaction of styrene (1a) with N-hydroxyphthalimide (2a). During the optimization, the oxidant and the iodine source, as well as the nature of the solvent and the

• ) substituents in the aromatic ring (products 3ca, 3da, 3fa, 3ha, 3cb–hb, yield 34–91%), and an electron-donating methyl group (products 3ba, 3ea, 3ga, 3bb, yield 39–85%). Good yields (60–79%) were achieved with a cyclic analogue of styrene – indene (1k, compounds 3ka, 3kb). β-Substituted styrenes (β-methyl

• styrene (1i) and (E)-stilbene (1j) also underwent the studied transformation giving iodo-oxyimides 3ia (yield 51%) and 3ja (yield 83%). The reaction of NHPI (2a) with p-methoxystyrene under standard conditions led to a complex mixture of products, possibly due to an increased tendency of the substrate to

Applications of organocatalysed visible-light photoredox reactions for medicinal chemistry

• Michael K. Bogdos,
• Emmanuel Pinard and
• John A. Murphy

Beilstein J. Org. Chem. 2018, 14, 2035–2064, doi:10.3762/bjoc.14.179

• novel difluoromethylating agent which was used to simultaneously install a difluoromethyl and an acetamide group on various styrene-type derivatives, under perylene-catalysed (Eox* (cat+•/cat) = −2.23 V vs ferrocene in acetonitrile) photoredox conditions (Scheme 14) [57]. For the most part, the scope of

Recent advances in hypervalent iodine(III)-catalyzed functionalization of alkenes

• Xiang Li,
• Pinhong Chen and
• Guosheng Liu

Beilstein J. Org. Chem. 2018, 14, 1813–1825, doi:10.3762/bjoc.14.154

• of styrene derivatives (Scheme 9) [58]. An iodoarene precatalyst 23 bearing the tertiary amide on the lactic side chains was the most effective. mCPBA was used as a stoichiometric oxidant and bismesylimide as an amine source. It is noteworthy that solvent was a key factor to suppress the undesired

• engages in double hydrogen bonding to form an 11-membered ring, resulting in the chiral helicity. The helical chirality induced in iodine(III) derivatives of 23 bearing the bislactamide motif was described for 27 with an efficient differentiation of the enantiotopic faces of the styrene substrate. This

β-Hydroxy sulfides and their syntheses

• Mokgethwa B. Marakalala,
• Edwin M. Mmutlane and
• Henok H. Kinfe

Beilstein J. Org. Chem. 2018, 14, 1668–1692, doi:10.3762/bjoc.14.143

• -epoxides, 2,3-epoxyalcohols as well as their OTMS, OTs and OPh derivatives. Reactions of 1-oxa-spiro[2.5]octane and 2-phenyloxirane (styrene oxide) with thiophenol both gave near quantitative yields of the hydroxy sulfides, with substitution occurring nearly exclusively at the sterically less hindered β

• cyclohexene oxide stereoselectively provided the trans-β-hydroxy sulfide as the only product whereas styrene oxide afforded the exclusive regioselective terminal alcohol products (Scheme 19). Both complexes could be easily recovered by filtration and were reused up to five times without any significant drop

•  27) [65]. Similar to the cyclodextrin-catalyzed methodology, the protocol is compatible with the presence of both electron-donating and electron-withdrawing substituents on the styrene and the disulfide but the reaction was found to be slightly slower. The presence of aerial oxygen is crucial to

Hypervalent organoiodine compounds: from reagents to valuable building blocks in synthesis

• Gwendal Grelier,
• Benjamin Darses and
• Philippe Dauban

Beilstein J. Org. Chem. 2018, 14, 1508–1528, doi:10.3762/bjoc.14.128

• reaction has been later found to be mediated by copper(I) cyanide starting from p-methoxystyrene [36]. However, under these conditions, other styrene derivatives bearing a phenyl, a tert-butyl, or an electron-withdrawing substituent have been shown to afford products resulting from a

• –I motif (Scheme 22) [62]. Hence aryl- and alkyl-substituted terminal alkynes can be coupled via a Sonogashira reaction when PPh3 is used as ligand, while the use of diphenylphosphinoferrocenyl ligand (dppf) allows the Heck-type coupling of acrylates, vinyl ketones and electron-poor styrene

Recent advances in phosphorescent platinum complexes for organic light-emitting diodes

• Cristina Cebrián and
• Matteo Mauro

Beilstein J. Org. Chem. 2018, 14, 1459–1481, doi:10.3762/bjoc.14.124

• electroluminescence performances in OLED devices. Solution-processed green-emitting PhOLEDs were prepared with the structure of ITO/poly(ethylenedioxythiophene):poly(styrene sulfonic acid) (PEDOT:PSS 70 nm)/mCP:24 5–50 wt % (60 nm)/SPPO13 (30 nm)/LiF (0.8 nm)/Al (100 nm), where SPPO13 is 2,7-bis(diphenylphosphoryl

Recent applications of chiral calixarenes in asymmetric catalysis

• Mustafa Durmaz,
• Erkan Halay and
• Selahattin Bozkurt

Beilstein J. Org. Chem. 2018, 14, 1389–1412, doi:10.3762/bjoc.14.117

• to the Scheme 31, led to the formation of uranyl and manganese complexes 106a,b–107a,b [70]. While Mn(III) complexes 107a,b have been used as catalysts for asymmetric epoxidation of styrene and substituted styrenes in the presence of NaClO as an oxygen donor and 4-phenylpyridine N-oxide (4-PPNO) as a

A survey of chiral hypervalent iodine reagents in asymmetric synthesis

• Soumen Ghosh,
• Suman Pradhan and
• Indranil Chatterjee

Beilstein J. Org. Chem. 2018, 14, 1244–1262, doi:10.3762/bjoc.14.107

• ) reagent 9b was used successively for the synthesis of δ-lactones 45 in a highly stereoselective manner starting from 44 [43]. The formation of cyclic iodonium 46 is the vital part of this difunctionalization process. Wirth et al. were the first to introduce asymmetric dioxytosylation of styrene (47) using

• Ishihara et al. Oxidative spirocyclization applying precatalyst 11 developed by Ciufolini et al. Asymmetric hydroxylative dearomatization. Enantioselective oxylactonization reported by Fujita et al. Dioxytosylation of styrene (47) by Wirth et al. Oxyarylation and aminoarylation of alkenes. Asymmetric

Bromide-assisted chemoselective Heck reaction of 3-bromoindazoles under high-speed ball-milling conditions: synthesis of axitinib

• Jingbo Yu,
• Zikun Hong,
• Xinjie Yang,
• Yu Jiang,
• Zhijiang Jiang and
• Weike Su

Beilstein J. Org. Chem. 2018, 14, 786–795, doi:10.3762/bjoc.14.66

• disubstituted olefins 2d and 2e could participate in the reaction to deliver 3ao (67%), 3ad (26%) and 3ae (27%). Finally, the steric hindrance of styrene was examined. Larger steric hindrance (2m) led to lower yield (58%) as compared with 2k (89%) and 2l (88%). Application in API synthesis To demonstrate the

Nanoreactors for green catalysis

• M. Teresa De Martino,
• Loai K. E. A. Abdelmohsen,
• Floris P. J. T. Rutjes and
• Jan C. M. van Hest

Beilstein J. Org. Chem. 2018, 14, 716–733, doi:10.3762/bjoc.14.61

• -proline 4b-catalyzed reactionsa: Asymmetric cyclopropanation reaction of styrene derivatives and ethyl diazoacetatea. Acknowledgements The authors acknowledge support from Horizon 2020 FET-Open program 737266 - ONE-FLOW; with regard to the graphical abstract we acknowledge Dennis Vriezema and Pille et al

Enantioselective dioxytosylation of styrenes using lactate-based chiral hypervalent iodine(III)

• Morifumi Fujita,
• Koki Miura and
• Takashi Sugimura

Beilstein J. Org. Chem. 2018, 14, 659–663, doi:10.3762/bjoc.14.53

• derivative was employed for the asymmetric dioxytosylation of styrene and its derivatives. The electrophilic addition of the hypervalent iodine(III) compound toward styrene proceeded with high enantioface selectivity to give 1-aryl-1,2-di(tosyloxy)ethane with an enantiomeric excess of 70–96% of the (S

• . [15][16][17] reported the dioxytosylation of styrene (1a, Scheme 1). Chiral hypervalent iodine reagents 2 bearing a 1-methoxyethyl side chain were used for enantiocontrol of the dioxytosylation, and the maximum enantiomeric excess (ee) of the product 3a reached 65%. Despite recent rapid progress in

• determined by 1H NMR using an internal standard. The ee of 3 was determined by chiral HPLC analysis. The results for the yields and ee are summarized in Table 1. The reaction of styrene (1a) with 4a gave the 1,2-dioxytosylated product 3a with 70% ee of the (S)-isomer (Table 1, entry 1). An ee of equal to or

Functionalization of N-arylglycine esters: electrocatalytic access to C–C bonds mediated by n-Bu₄NI

• Mi-Hai Luo,
• Yang-Ye Jiang,
• Kun Xu,
• Yong-Guo Liu,
• Bao-Guo Sun and
• Cheng-Chu Zeng

Beilstein J. Org. Chem. 2018, 14, 499–505, doi:10.3762/bjoc.14.35

• . In addition, naphthanols were also compatible in this transformation, giving the corresponding products 3ae–3ag in good yields. Notably, when styrene and 1-ethynylbenzene were subjected to reaction with 1a under the standard indirect electrolytic conditions, quinoline-2-carboxylate 3ah was isolated

• in 64% and 58% yield, respectively. Substituted styrenes and 1-ethynylbenzene were also tolerated well, giving corresponding products 3ai–3aj in 45–50% yields. The formations of 3ah–3aj likely derives from an azo-Diels–Alder reaction of styrene or ethynylbenzene with an imine intermediate, in situ

Photocatalytic formation of carbon–sulfur bonds

• Alexander Wimmer and
• Burkhard König

Beilstein J. Org. Chem. 2018, 14, 54–83, doi:10.3762/bjoc.14.4

• visible-light irradiation of the photoorganocatalyst. Aliphatic and aromatic thiols reacted with aliphatic olefins and styrene derivatives in high yields. Recently, additional procedures for the photoredox-catalyzed radical thiol–ene and thiol–yne reaction were reported. Xia and co-workers describe a

• and were able to couple a series of electron-rich and electron-poor styrene derivatives with aromatic and also long-chain aliphatic thiols to the respective sulfoxides, after aerobic oxidation (Scheme 15a). They describe a photocatalyzed thiol–ene reaction mechanism, where the sulfide-adduct is

• Eosin Y radical anion. After radical addition of the thiocyanate radical to styrene, the anti-Markovnikov intermediate can form a peroxy radical species with molecular oxygen. Consecutive rearrangements give a β-hydroxythiocyanate, which undergoes fast cyclization to the 5-membered heterocyclic product

CF₃SO₂X (X = Na, Cl) as reagents for trifluoromethylation, trifluoromethylsulfenyl-, -sulfinyl- and -sulfonylation and chlorination. Part 2: Use of CF₃SO₂Cl

• Hélène Chachignon,
• Hélène Guyon and
• Dominique Cahard

Beilstein J. Org. Chem. 2017, 13, 2800–2818, doi:10.3762/bjoc.13.273

• introduction of the CF3 moiety and a Cl atom onto alkenes or alkynes. Kamigata’s group was the first to report such type of transformation in 1989 [23][24]. In the presence of RuCl2(PPh3)2 at 120 °C, a variety of styrene derivatives as well as cyclic and acyclic alkenes were converted into their

• chlorotrifluoromethylated analogues (Scheme 16). Generally, the reaction proceeded particularly well with terminal and internal alkenes carrying an electron-withdrawing group. On the contrary, styrene derivatives bearing an electron-donating group provided less satisfying yields. Such results can be explained by the

• were obtained for styrene derivatives, although with a subsequent dehydrochlorination step. If the nature of the substrate undoubtedly played an important role in the reaction process, it was also the case of the catalyst. Indeed, the use of other usual photocatalysts such as [Ru(bpy)3]Cl2, [Ir(ppy)2

CF₃SO₂X (X = Na, Cl) as reagents for trifluoromethylation, trifluoromethylsulfenyl-, -sulfinyl- and -sulfonylation. Part 1: Use of CF₃SO₂Na

• Hélène Guyon,
• Hélène Chachignon and
• Dominique Cahard

Beilstein J. Org. Chem. 2017, 13, 2764–2799, doi:10.3762/bjoc.13.272

• radical [ArN(CO2Me)O•] 33, would lead to two regioisomeric oxytrifluoromethylated products. Fortunately, this issue was solved by the primary formation of the CF3 radical and thus a regioselective addition. After optimization of the reaction conditions with styrene as model alkene, the method was applied

• to a wide range of alkenes featuring various functional groups. Further reduction of the N–O bond by Mo(CO)6 gave the corresponding alcohols. A protocol free of peroxide initiator was developed by Yang, Vicic and co-workers using a manganese salt and O2 from air [35]. Styrene derivatives were

• ) addition of TEMPO suppressed the reaction; (ii) an induction period was observed followed by acceleration with consumption of styrene; (iii) vinyl triflone was detected indicating the formation of CF3SO2•; (iv) formation of CF3SO3– via oxidation of CF3SO2• (Scheme 16). A metal-free approach with in situ

Palladium-catalyzed Heck-type reaction of secondary trifluoromethylated alkyl bromides

• Tao Fan,
• Wei-Dong Meng and
• Xingang Zhang

Beilstein J. Org. Chem. 2017, 13, 2610–2616, doi:10.3762/bjoc.13.258

• substrate scope and high efficiency. The reaction can also extend to secondary difluoroalkylated alkyl iodide. Preliminary mechanistic studies reveal that a secondary alkyl radical via a SET pathway is involved in the reaction. Results and Discussion We began this study by choosing styrene (1a) and 2-bromo

• (Table 1, entry 14). With the optimized reaction conditions in hand, a variety of alkenes were examined. As shown in Scheme 1, reactions of 2a with a series of styrene derivatives 1 proceeded smoothly and provided 3 in moderate to excellent yields (Scheme 1). Generally, substrates bearing electron