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

• , where the byproducts typically associated with free carbene formation (e.g., dimerization or rearrangement) were not observed (Scheme 2). In 1988, Hadjiarapoglou was investigating transition metal- and photocatalyzed intermolecular cyclopropanations between ylide 8 and norbornene, and found indane 9 was

Bromination of endo-7-norbornene derivatives revisited: failure of a computational NMR method in elucidating the configuration of an organic structure

• Demet Demirci Gültekin,
• Arif Daştan,
• Yavuz Taşkesenligil,
• Cavit Kazaz,
• Yunus Zorlu and
• Metin Balci

Beilstein J. Org. Chem. 2023, 19, 764–770, doi:10.3762/bjoc.19.56

• by NMR experiments. Mechanism: For the formation of the compound 6 we proposed the following mechanism: the double bond in norbornene is pyramidalized in the endo direction [11]. Norbornene exclusively undergoes an exo attack upon treatment with bromine. This exo selectivity [12][13] in norbornene

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

• precursor 102 and the complementary aldehyde 103. 3.4 Catellani-type reaction The Catellani reaction involves palladium-norbornene cooperative catalysis to functionalise the ortho- and ipso-positions of aryl halides by alkylation, arylation, amination, acylation, thiolation, etc. [63]. Della Ca' et al. [64

• ] reported the synthesis of substituted dibenzo[b,f]azepines 110 as unexpected products during their investigation of the Catellani reaction. The Pd-catalysed reaction of an aryl iodide 106, bromoaniline 107, norbornadiene (108) and base resulted in the norbornene-azepine intermediate 109. Heating to 130 °C

• coupling in dibenzo[b,f]oxepine synthesis. Wittig reaction and Ullmann coupling as key steps in dihydrobenz[b,f]oxepine synthesis. Pd-catalysed dibenzo[b,f]azepine synthesis via norbornene azepine intermediate 109. A simple representation of olefin metathesis resulting in transalkylidenation. Ring-closing

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

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

• difunctionalization of norbornene derivatives 15 with alkynes (Scheme 3) [35]. It was noted the reaction is amenable to both electron-donating groups (EDGs) and electron-withdrawing groups (EWGs); however, yields were diminished with increasing electron deficiency. Moreover, the use of the bulkier tert

• -butyldimethylsilyl-protecting group resulted in the corresponding 1,5-enyne only being produced in a 33% yield. Several different norbornene derivatives were explored and gave the anticipated exo,exo-difunctionalized product in good yield. In contrast, when using an ethylene-bridged bicycloalkene to generate the

• norbornene derivatives 15 using imides 27 and tetraarylborates 28 (Scheme 5) [37]. The method utilizes C–N bond activation to trigger the reaction. The authors demonstrated a broad reaction scope. Electron-deficient amides were shown to perform worse than their electron-rich counterparts with the p

Complementarity of solution and solid state mechanochemical reaction conditions demonstrated by 1,2-debromination of tricyclic imides

• Petar Štrbac and
• Davor Margetić

Beilstein J. Org. Chem. 2022, 18, 746–753, doi:10.3762/bjoc.18.75

• ] could be simplified by in situ generation of the catalyst. Moreover, in the debromination of norbornene imide 11, the expected Diels−Alder adduct with furan was not obtained, but compound 12 incorporating a tetrahydrofuran ring at position 2, presumably by radical reaction (Figure 2) [19][20]. We

• its synthetic utility were investigated employing various dienes such as furan (18), 1,3-diphenylisobenzofuran (24) (DPIBF) and substituted anthracenes 31, 36 and 39 (Figure 3). Exclusive norbornene exo-π selectivity [24] was observed in all cycloadddition reactions. Selected five-membered dienes were

• could be also obtained by cycloaddition parity reversal principle [16][36], employing norbornene dibromide 11 and furan (18). Ball milling reaction without THF (neat grinding) provided 22 as the major product, together with a minor amount of dehalogenated product 40 (Scheme 2). When THF was added for

Ready access to 7,8-dihydroindolo[2,3-d][1]benzazepine-6(5H)-one scaffold and analogues via early-stage Fischer ring-closure reaction

• Irina Kuznetcova,
• Felix Bacher,
• Daniel Vegh,
• Hsiang-Yu Chuang and
• Vladimir B. Arion

Beilstein J. Org. Chem. 2022, 18, 143–151, doi:10.3762/bjoc.18.15

• -catalyzed norbornene-mediated C–H activation [35] failed and gave 1,4-bis(2-bromophenyl)piperazine-2,5-dione (22, Scheme 5) as the sole product in 61% yield, which to our knowledge is not documented in the literature yet. Synthetic pathway (c) started from methyl 4-(2-nitrophenyl)-3-oxobutanoate prepared in

Cryogels: recent applications in 3D-bioprinting, injectable cryogels, drug delivery, and wound healing

• Luke O. Jones,
• Leah Williams,
• Tasmin Boam,
• Martin Kalmet,
• Chidubem Oguike and
• Fiona L. Hatton

Beilstein J. Org. Chem. 2021, 17, 2553–2569, doi:10.3762/bjoc.17.171

• tetrazine-norbornene coupling. Laponite nanoparticles were then incorporated within the walls of the cryogel. The results showed the so-called “click alginate” was able to produce cryogels with an interconnected porous structure, and high deformability allowing it to be used through a 16-gauge needle. The

Catalyzed and uncatalyzed procedures for the syntheses of isomeric covalent multi-indolyl hetero non-metallides: an account

• Ranadeep Talukdar

Beilstein J. Org. Chem. 2021, 17, 2102–2122, doi:10.3762/bjoc.17.137

• process, where hydrosilanes 41 were treated with an excess amount of indoles (Scheme 7a and Scheme 7b) [60]. Brookhart’s acid [H(OEt2)2]+[BArF4]− (42) was used to generate ether-stabilized silicon cations of type 46 and norbornene was added as a proton scavenger [64]. Following this procedure, Yonekura

On the application of 3d metals for C–H activation toward bioactive compounds: The key step for the synthesis of silver bullets

• Renato L. Carvalho,
• Amanda S. de Miranda,
• Mateus P. Nunes,
• Roberto S. Gomes,
• Guilherme A. M. Jardim and
• Eufrânio N. da Silva Júnior

Beilstein J. Org. Chem. 2021, 17, 1849–1938, doi:10.3762/bjoc.17.126

• , antipsychotic (12) [54], anticonvulsant (13) [55], and antiparkinsonian activities (14) [56][57] (Scheme 5A). A few years earlier, Hou and co-workers reported the very first metal-catalyzed C–H hydroaminoalkylation of tertiary amines using norbornene as the coupling partner [41]. For this method, the scandium

• catalyst that presented the best performance was a homoleptic trialkylscandium, [Sc-3] (Scheme 6B), instead of the usual cyclopentadienyl-containing dialkylscandium catalysts described so far in this review. Several substituted norbornene derivatives were obtained in good to excellent yields (Scheme 6C

Development of N-F fluorinating agents and their fluorinations: Historical perspective

• Teruo Umemoto,
• Yuhao Yang and
• Gerald B. Hammond

Beilstein J. Org. Chem. 2021, 17, 1752–1813, doi:10.3762/bjoc.17.123

CF₃-substituted carbocations: underexploited intermediates with great potential in modern synthetic chemistry

• Anthony J. Fernandes,
• Armen Panossian,
• Bastien Michelet,
• Agnès Martin-Mingot,
• Frédéric R. Leroux and
• Sébastien Thibaudeau

Beilstein J. Org. Chem. 2021, 17, 343–378, doi:10.3762/bjoc.17.32

Diels–Alder reaction of β-fluoro-β-nitrostyrenes with cyclic dienes

• Savva A. Ponomarev,
• Roman V. Larkovich,
• Alexander S. Aldoshin,
• Andrey A. Tabolin,
• Sema L. Ioffe,
• Jonathan Groß,
• Till Opatz and
• Valentine G. Nenajdenko

Beilstein J. Org. Chem. 2021, 17, 283–292, doi:10.3762/bjoc.17.27

• activation parameters. Furthermore, the synthetic utility of the cycloadducts obtained was demonstrated. Keywords: Diels–Alder reaction; fluorine; nitrostyrene; norbornene; stereochemistry; Introduction Organofluorine compounds play an exceptionally important role in various fields of science and

• by 2018, the total number of publications and patents related to the production and use of norbornene and norbornadiene derivatives had exceeded 30,000 [58]. Indeed, norbornene and its derivatives have found application in medicine, agriculture, microelectronics, and rocket technology as well as in

• production of polymeric materials, efficient gas separation membranes and solar energy converters [58]. Considering the high interest in such structures and the unique role of fluorine, we believe that novel norbornene derivatives obtained in the framework of this study can become relevant compounds in

Synthesis of novel fluorinated building blocks via halofluorination and related reactions

• Attila Márió Remete,
• Tamás T. Novák,
• Melinda Nonn,
• Matti Haukka,
• Ferenc Fülöp and
• Loránd Kiss

Beilstein J. Org. Chem. 2020, 16, 2562–2575, doi:10.3762/bjoc.16.208

• both NOESY measurements and single-crystal X-ray diffraction (Figure 2 and Figure 3). The next rigid bicyclic system studied was the methyl diendo norbornene dicarboxylate 16. The treatment of 16 with NBS/Deoxo-Fluor® yielded the bromolactone (rac)-17a [37]. The reaction, when repeated only with NBS

• bromonium ions of norbornene systems, such rearrangements are not uncommon [38][39][40]. Then, the carbenium ion motif of (rac)-T7a–c can be attacked from both sides to give the products (rac)-20a–c and (rac)-21a–c (Scheme 13). The formation mechanism of the product 22, however, is still an open question

Pauson–Khand reaction of fluorinated compounds

• Jorge Escorihuela,
• Daniel M. Sedgwick,
• Alberto Llobat,
• Mercedes Medio-Simón,
• Pablo Barrio and
• Santos Fustero

Beilstein J. Org. Chem. 2020, 16, 1662–1682, doi:10.3762/bjoc.16.138

• transformation widely used in the synthesis of polycyclic complex molecules. The intermolecular variant shows a wide alkyne scope, but in terms of the olefin counterpart is limited to the use of ethylene or strained alkenes, such as norbornene and norbornadiene. The high prevalence of five-membered ring systems

• Co–C bond. These electronic effects have been shown to be less important than steric ones, and are often overcome by the latter. Regarding the stereochemistry, exo-products are almost exclusively obtained for norbornene and norbornadiene. Many deviations from the classic reaction conditions have been

• selectivity of simple alkenes. In this regard, most examples have been restricted to the use of ethylene or strained alkenes such as cyclopropene, norbornene, norbornadiene, (E)-cyclooctene, or bicyclo[3.2.0]hept-6-ene [67][68][69]. The first example of an intermolecular version of fluorinated compounds was

Aldehydes as powerful initiators for photochemical transformations

• Maria A. Theodoropoulou,
• Nikolaos F. Nikitas and
• Christoforos G. Kokotos

Beilstein J. Org. Chem. 2020, 16, 833–857, doi:10.3762/bjoc.16.76

• proceeded efficiently for a wide range of substrates in moderate to excellent yield, including various alkyl halides 93, carbon tetrachloride, 2-norbornene, cyclic alkenes, a terminal disubstituted olefin, and a terminal alkyne. The reaction mechanism was thought to proceed via energy transfer from the

An overview of the cycloaddition chemistry of fulvenes and emerging applications

• Ellen Swan,
• Kirsten Platts and
• Anton Blencowe

Beilstein J. Org. Chem. 2019, 15, 2113–2132, doi:10.3762/bjoc.15.209

• metathesis polymerisation (ROMP) to generate facially amphiphilic polymers [182][235][237][238]. Ilker et al. employed the DAC between alkyl pentafulvenes and maleic anhydride to initially prepare norbornene anhydride monomers that could be further functionalised to afford norbornene imide monomers (Scheme

• phospholipid unilamellar vesicles at low concentrations (5 µg/mL), and in a dose and molecular weight dependent fashion, indicating their potential antimicrobial properties. Further studies revealed that co-polymerisation of norbornene imide monomers with different alkyl groups provided optimal antimicrobial

• [190]. Preparation of hydrogels via Diels–Alder cycloaddition with fulvene-conjugated dextran and dichloromaleic acid-modified poly(ethylene glycol) [191]. Ring-opening metathesis polymerisation of norbornene derivatives derived from fulvenes and maleimides to furnish facially amphiphilic polymers

Hoveyda–Grubbs catalysts with an N→Ru coordinate bond in a six-membered ring. Synthesis of stable, industrially scalable, highly efficient ruthenium metathesis catalysts and 2-vinylbenzylamine ligands as their precursors

• Kirill B. Polyanskii,
• Kseniia A. Alekseeva,
• Pavel V. Raspertov,
• Pavel A. Kumandin,
• Eugeniya V. Nikitina,
• Atash V. Gurbanov and
• Fedor I. Zubkov

Beilstein J. Org. Chem. 2019, 15, 769–779, doi:10.3762/bjoc.15.73

• (14) for CM reactions, ii) diethyl diallylmalonate (17) and diallyltosylamide (19) for RCM reactions, iii) norbornene (21) and styrene/hex-1-ene for ROCM metathesis reactions. This selection of model subtests for metathesis is also explained by the possibility to control the course of metathesis and

• ), catalysts 11a,b did not provide high selectivity (Table 3, entries 34–37). Interactions of norbornene (21) with a two-fold excess of styrene (12) or hex-1-ene (24) was accompanied by the CM reaction, which provided products of the ring opening (22, 23, 25, 26) and significant amounts of byproducts due to

• the side cross metathesis (13 and 27). Moreover, sparingly soluble high molecular weight products were isolated from all reactions; according to gel permeation chromatography data, these solids are, presumably, norbornene oligomers (see, for example data for entry 35, Supporting Information File 1 and

Synthesis of polydicyclopentadiene using the Cp₂TiCl₂/Et₂AlCl catalytic system and thin-layer oxidation of the polymer in air

• Zhargolma B. Bazarova,
• Ludmila S. Soroka,
• Alex A. Lyapkov,
• Мekhman S. Yusubov and
• Francis Verpoort

Beilstein J. Org. Chem. 2019, 15, 733–745, doi:10.3762/bjoc.15.69

• ; polydicyclopentadiene; thin layers; Introduction Currently, polymerization of dicyclopentadiene and norbornene derivatives applying various catalyst systems is of great interest [1][2][3][4][5][6][7]. Dicyclopentadiene (DCPD) is a secondary product of the ethylene and propylene production and is used as a monomer to

• bond from the norbornene ring of dicyclopentadiene in the double bond reaction, as a result of the rearrangement of the active site, structures of both exo- and endo-polydicyclopentadiene (A and B, see Scheme 2) can be formed [1][10]. At the same time, with participation in the reaction of the

Aqueous olefin metathesis: recent developments and applications

• Valerio Sabatino and
• Thomas R. Ward

Beilstein J. Org. Chem. 2019, 15, 445–468, doi:10.3762/bjoc.15.39

• ; Introduction Olefin metathesis represents a versatile synthetic tool for the construction of carbon–carbon bonds [1][2][3][4][5][6][7][8][9]. Since its first report in 1956, a Ti(II)-catalyzed polymerization of norbornene [10], metathesis rapidly attracted interest among organic chemists and has been used in

• ][53]. Grubbs and co-workers were the first to introduce water-soluble catalysts which displayed metathesis activity in aqueous media [54]. In 1996, Grubbs et al. reported that complexes 1 and 2 catalyze the living opening polymerization of norbornene derivatives 35 and 36 in neat water. Interestingly

• publication, catalyst 9 was used for an aqueous living ring-opening metathesis polymerization-induced self-assembly (ROMPISA). The authors demonstrated the possibility of performing living ROMP in water selecting a quaternary ammonium-based phenyl norbornene carboximide as core-forming monomer [60]. This

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

• POSS-substituted norbornene (or other ROMP susceptible cycloolefins) are discussed. Emphasis was put on the synthetic and catalytic aspects rather than on the properties and applications of synthesized materials. Keywords: olefin metathesis; POSS; silsesquioxanes; Introduction Silsesquioxanes are

• polymerization (ROMP) of POSS-substituted norbornene (or other ROMP susceptible cycloolefins, Scheme 2). Nearly all metathetic transformations described in this review have been performed in the presence of commonly used ruthenium-based catalysts (Figure 3). In contrast, there are only a few examples of

• cage should be used. Due to the ease of polymerization and functionalization, norbornene derivatives are the most often used monomers. The aim of this section is to indicate the applications of ROMP in the synthesis of hybrid materials containing the POSS moiety covalently bonded to organic polymeric

A novel and efficient synthesis of phenanthrene derivatives via palladium/norbornadiene-catalyzed domino one-pot reaction

• Yue Zhong,
• Wen-Yu Wu,
• Shao-Peng Yu,
• Tian-Yuan Fan,
• Hai-Tao Yu,
• Nian-Guang Li,
• Zhi-Hao Shi,
• Yu-Ping Tang and
• Jin-Ao Duan

Beilstein J. Org. Chem. 2019, 15, 291–298, doi:10.3762/bjoc.15.26

• functional groups. Subsequently, facile one-pot approaches had been realized via norbornene-mediated palladium-catalyzed Catellani reaction by Lautens’ group [10] (Scheme 1c). Though this strategy was superior to previous methods in terms of mildness of the reaction conditions, it had a limited substrate

• scope and relatively low reaction efficiency. Very recently, Fuk Yee Kwong and co-workers (Scheme 1d) developed a straightforward one pot π-extension method using norbornadiene instead of norbornene as directing group to afford the phenanthrenes [11]. However, ortho-haloaryl carboxylic acids employed in

• this approach had low reactivity, which needed higher reaction temperatures and longer reaction time. Therefore, the development of novel, efficient, and highly functional group tolerant methods for the synthesis of phenanthrene derivatives is still desirable. Domino reactions such as norbornene

Olefin metathesis in multiblock copolymer synthesis

• Maria L. Gringolts,
• Yulia I. Denisova,
• Eugene Sh. Finkelshtein and
• Yaroslav V. Kudryavtsev

Beilstein J. Org. Chem. 2019, 15, 218–235, doi:10.3762/bjoc.15.21

• norbornadiene (NB–(PPE–PMI)–NB) to allow further functionalization through olefin metathesis. The separately prepared by ROMP living diblock copolymers comprising norbornene with OEG (A block) and an NHS (B block) were synthesized in the presence of Gr1 and terminated by the reaction with NB–(PPE–PMI)–NB to

• (cyclohexene carbonate)s was carried out by the β-diiminate (BDI) zinc-catalyzed block copolymerization of functionalized epoxides and CO2 with a norbornenyl-containing initiator (Scheme 5) [68]. The subsequent “grafting through” by ROMP of norbornene resulted in the synthesis of multiblock copolymer brushes

• . Changes in the synthetic stage sequence led to variable layer compositions. Various linear and star-shaped (triarm) ABA and ABCBA amphiphilic multiblock copolymers containing acetal-protected sugars (APS) were prepared by the coupling of an end-functionalized ROMP copolymer of norbornene (NB) and APS

Catalysis of linear alkene metathesis by Grubbs-type ruthenium alkylidene complexes containing hemilabile α,α-diphenyl-(monosubstituted-pyridin-2-yl)methanolato ligands

• Tegene T. Tole,
• Johan H. L. Jordaan and
• Hermanus C. M. Vosloo

Beilstein J. Org. Chem. 2019, 15, 194–209, doi:10.3762/bjoc.15.19

• temperatures in the ROMP of norbornene and cyclooctene. Oligomers were obtained at room temperature in the presence of 4a and 4d, while 4b and 4c yielded polymers. At 60 °C, ROMP was observed with norbornene (98–100%) and cyclooctene (72–80%) in the presence of 4. We investigated a number of Grubbs 1- and

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

• Technology of Ministry of Education, Hangzhou Normal University, Hangzhou, Zhejiang 311121, China 10.3762/bjoc.15.4 Abstract At 0 °C in THF in the presence of Grubbs first generation catalyst, cyclobutene derivatives undergo ROMP readily, whereas norbornene derivatives remain intact. When the substrate

• contains both cyclobutene and norbornene moieties, the conditions using THF as the solvent at 0 °C offer a useful protocol for the selective ROMP of cyclobutene to give norbornene-appended polycyclobutene. Unsymmetrical ladderphane having polycyclobutene and polynorbornene as two strands is obtained by

• further ROMP of the norbornene appended polycyclobutene in the presence of Grubbs first generation catalyst in DCM at ambient temperature. Methanolysis of this unsymmetrical ladderphane gives polycyclobutene methyl ester and insoluble polynorbornene-amide-alcohol. The latter is converted into the