Advancements in hydrochlorination of alkenes

• Daniel S. Müller

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

• unfortunately data in the absence of ZnCl2 was not provided by the authors. ZnCl2 has been previously reported as a catalyst for hydrochlorination reactions, notably in the case of cyclooctene (25) with HCl in benzene (Scheme 5D) [47]. The use of ZnCl2 as a catalyst for hydrochlorinations dates back to a patent

• of HCl. No reaction was observed for terminal and 1,2-disubstituted alkenes such as cyclooctene (25) and 1-decene (53). Boudjouk and co-workers examined PCl3, SnCl4, SOCl2, SiCl4, Me2SiCl2, and Me3SiCl as hydrogen chloride sources [55]. They found that PCl3 and SnCl4 gave the desired

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

• standing out. The first one (strategy 1, Figure 3) consists in the successive formation of the eight-membered ring B followed by construction of the five-membered ring C: i.e., the cyclooctene ring is built first from a suitably substituted cyclopentane substrate, which then serves as a precursor for the

• ] cyclooctene 27 in very high yield. The final stages of the synthesis corresponded to the elaboration of the second cyclopentenone ring allowing access to ent-fusicoauritone (28) in 24 steps. 1.1.1.2 Strategy 2: Late-stage formation of the 8-membered ring: Ophiobolins belong to the family of sesterterpenoids

• steric hindrance, alcohol 47 was converted into triene 48 upon dehydration, and further engaged in the RCM reaction. In this case, the use of HG-II catalyst proved to be the best choice to achieve cyclooctene ring formation giving rise to intermediate 49, providing entries for further functionalization

Germacrene B – a central intermediate in sesquiterpene biosynthesis

• Houchao Xu and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2023, 19, 186–203, doi:10.3762/bjoc.19.18

• hypothetical (E)-cyclohexene or (E)-cycloheptene would be too strained, the smallest possible ring with an E configuration is (E)-cyclooctene). In some cases the initially formed neutral product can become reprotonated to initiate a second round of cyclisation reactions which usually leads to compounds of

Efficient synthesis of aziridinecyclooctanediol and 3-aminocyclooctanetriol

• Emine Salamci and
• Ayse Kilic Lafzi

Beilstein J. Org. Chem. 2022, 18, 1539–1543, doi:10.3762/bjoc.18.163

• Emine Salamci Ayse Kilic Lafzi Department of Chemistry, Faculty of Sciences, Atatürk University, 25240 Erzurum, Turkey 10.3762/bjoc.18.163 Abstract Cyclooctene endoperoxide was used as the key compound for the synthesis of aziridinecyclooctanediol and 3-aminocyclooctanetriol. Reduction of the

• cyclooctene endoperoxide, prepared by photooxygenation of cis,cis-1,3-cyclooctadiene, with zinc gave a cyclooctenediol and then benzylation of the hydroxy group yielded dibenzylated cyclooctene. Oxidation of the latter compound by OsO4/NMO followed by mesylation of the hydroxy group provided bis(benzyloxy

• )cyclooctene 6 in 70% yield (Scheme 1). Oxidation of the dibenzylated compound 6 with OsO4/NMO provided the corresponding diol 7 in 90% yield. The exact configuration of 7 was confirmed by 1H and 2D NMR spectroscopic data. Next, mesylation of the hydroxy groups in 7 with MsCl in pyridine yielded dimesylate 8

Mechanochemical synthesis of unsymmetrical salens for the preparation of Co–salen complexes and their evaluation as catalysts for the synthesis of α-aryloxy alcohols via asymmetric phenolic kinetic resolution of terminal epoxides

• Shengli Zuo,
• Shuxiang Zheng,
• Jianjun Liu and
• Ang Zuo

Beilstein J. Org. Chem. 2022, 18, 1416–1423, doi:10.3762/bjoc.18.147

• ]. Jones et al. designed a cyclooctene-based Co–salen macrocycle catalyst for the phenolic KR of epichlorohydrin and 1,2-epoxyhexane [21]. However, these Co–salen systems suffer from several limitations such as tedious preparation of salen scaffolds, excess use of epoxides, high catalyst loadings, narrow

A comprehensive review of flow chemistry techniques tailored to the flavours and fragrances industries

• Guido Gambacorta,
• James S. Sharley and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2021, 17, 1181–1312, doi:10.3762/bjoc.17.90

Stereoselective syntheses of 3-aminocyclooctanetriols and halocyclooctanetriols

• Emine Salamci and
• Yunus Zozik

Beilstein J. Org. Chem. 2021, 17, 705–710, doi:10.3762/bjoc.17.59

• are reported. Reduction of cyclooctene endoperoxide, obtained by photooxygenation of cis,cis-1,3-cyclooctadiene, with zinc yielded a cyclooctene diol followed by acetylation of the hydroxy group, which gave dioldiacetate by OsO4/NMO oxidation. The cyclooctane dioldiacetate prepared was converted to

Insight into functionalized-macrocycles-guided supramolecular photocatalysis

• Minzan Zuo,
• Krishnasamy Velmurugan,
• Kaiya Wang,
• Xueqi Tian and
• Xiao-Yu Hu

Beilstein J. Org. Chem. 2021, 17, 139–155, doi:10.3762/bjoc.17.15

• supramolecular chiral interactions but can also improve the photoenantiodifferentiating proficiency of the host. To prove this concept, Inoue et al. investigated the photoisomerization of (Z)-cyclooctene ((Z)-6) to the chiral E-isomer (E)-6 in an aqueous methanol solution through host–guest interactions between

• . Cibulka et al., Catalytic Photooxidation of 4‐Methoxybenzyl Alcohol with a Flavin–Zinc(II)‐Cyclen Complex, Chemistry – A European Journal, John Wiley and Sons. Enantiodifferentiating Z–E photoisomerization of cyclooctene sensitized by a chiral sensitizer as the host. Adapted with permission from [24

Direct synthesis of anomeric tetrazolyl iminosugars from sugar-derived lactams

• Michał M. Więcław and
• Bartłomiej Furman

Beilstein J. Org. Chem. 2021, 17, 115–123, doi:10.3762/bjoc.17.12

• (cyclooctene)iridium dimer ([Ir(coe)2Cl]2) can act as the catalyst in combination with Et2SiH2 [15]. Surprisingly, they were able to obtain imines as well as amines using this methodology. Based on the works of Nagashima [16], an iridium-based protocol for tertiary amides was introduced by Dixon [17][18][19

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

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

• 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

Oxime radicals: generation, properties and application in organic synthesis

• Igor B. Krylov,
• Stanislav A. Paveliev,
• Alexander S. Budnikov and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2020, 16, 1234–1276, doi:10.3762/bjoc.16.107

• two products: the product obtained by pathway A (26a) and a product 26b unique to pathway B. The abstraction–addition process (B) is dominant for three alkenes studied, namely, cyclohexene, cyclooctene, and 3-hexene, with 90–92% of the overall reaction occurring by this mechanism [77]. The reactions

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

• heptacyclopentylnorbornenylethyloctasilsesquioxane and its copolymerization with cyclooctene [43]. The obtained copolymer was subsequently hydrogenated to afford polyethylene–POSS random copolymer (Scheme 21). Thermogravimetric analysis of the polyethylene–POSS copolymers under air showed a significant improvement of the thermal stability relative

• diolefins. Acyclic diene metathesis copolymerization of DDSQ-2GeVi with diolefins. Ring-opening metathesis copolymerization of norbornenylethyl-POSS with norbornene. Synthesis of a polyethylene–POSS copolymer via ring-opening metathesis copolymerization of norbornenylethyl-POSS with cyclooctene and

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

• -substituted NB with poly(ethylene glycol) (PEG) [69]. Ring-opening metathesis copolymerization of the rather strained cyclooctene (COE) and a strainless 27-membered macrocyclic olefin (MCO) led to the multiblock copolymer consisting of octenylene blocks linked with ring-opened MCO segments (Scheme 6) [70

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

• -quinolinolate Grubbs 2-type derivative, patented by Slugovc and Wappel [15] for use in ROMP reactions, was found to be inactive (<1% conversion) for 1-octene metathesis at 60 °C [12]. Schachner et al. [16] evaluated the catalytic activity of 5b, 5d and related complexes for the ROMP of cyclooctene, CM of hex-5

• of methyl 9-dodecene and in hexane for the RO-RCM of cis-cyclooctene. The above-mentioned studies clearly illustrate the versatility and use of ruthenium alkylidene complexes with pyridinyl-alcoholato ligands. In principle these studies had one approach in common concerning the pyridinyl-alcoholato

Ammonium-tagged ruthenium-based catalysts for olefin metathesis in aqueous media under ultrasound and microwave irradiation

• Łukasz Gułajski,
• Andrzej Tracz,
• Katarzyna Urbaniak,
• Stefan J. Czarnocki,
• Michał Bieniek and
• Tomasz K. Olszewski

Beilstein J. Org. Chem. 2019, 15, 160–166, doi:10.3762/bjoc.15.16

• ], dodecyltrimethylammonium bromide (DTAB) [36], polymerised cyclooctadiene (COD) and cyclooctene (COE) [37], sodium dodecyl sulphate (SDS) [38] or DL-α-tocopherol methoxypolyethylene glycol succinate solution (TPGS-750-M) [39], to improve the solubility of reacting species and/or performance of the catalyst. Recent progress

Ruthenium-based olefin metathesis catalysts with monodentate unsymmetrical NHC ligands

• Veronica Paradiso,
• Chiara Costabile and
• Fabia Grisi

Beilstein J. Org. Chem. 2018, 14, 3122–3149, doi:10.3762/bjoc.14.292

• ) with cyclooctene (COE, 47) and cyclopentene (CPE, 48), respectively (Scheme 6). An NBE/COE ratio of 1:50 was found necessary to realize a copolymer containing 97% of alternating diads ([poly(NBE-alt-COE)n]), while an NBE/CPE ratio of only 1:7 resulted in the formation of a copolymer with roughly 90% of

• substituent (Figure 15) at the nitrogen atoms were investigated by Copéret and Thieuleux et al. in the tandem ring-opening–ring-closing alkene metathesis (RO–RCM) of cis-cyclooctene (47) and their performance were compared to those of the classical GII-SIMes and GII-IMes [29]. The dissymmetry of the NHC

• ligand in 59 and 60 allowed for the selective formation of cyclic dimeric and trimeric products in place of polymers from cyclooctene, while the symmetrical analogues GII-SIMes and GII-IMes led mainly to polymers (Figure 15). Following a study on degenerate metathesis reactions that had highlighted a

Ring-opening metathesis of some strained bicyclic systems; stereocontrolled access to diolefinated saturated heterocycles with multiple stereogenic centers

• Zsanett Benke,
• Melinda Nonn,
• Márton Kardos,
• Santos Fustero and
• Loránd Kiss

Beilstein J. Org. Chem. 2018, 14, 2698–2707, doi:10.3762/bjoc.14.247

• (5 mol %), leading at 20 °C to δ-lactone derivative (±)-15 although with low yield (Scheme 6, Table 4). In continuation, we selected a cyclooctene-fused system, namely isoxazoline (±)-16 which, in turn, was accessed through nitrile–oxide dipolar cycloaddition, by using nitroethane, DMAP and Boc2O

• cyclooctene-fused isoxazoline (±)-16. ROM and transformations of lactam (±)-18. Isolated yields for compound (±)-5 formed in the ring-opening reaction of lactone (±)-3 with ethylene in ROM reactions with various catalysts. Isolated yields for compound (±)-6 formed in the ring-opening reaction of lactone (±)-4

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

• (OMe) in DMA at 70 °C. Employing [RhCl(coe)]2 (coe = cyclooctene) and P(Mes)3 ((P(Mes)3 = tris(2,4,6-trimethylphenyl)phosphine) as the catalyst, the carboxylated product 30a was obtained in 67% yield, along with the formation of a methylated byproduct 31a. Other phosphine ligands such as PPh3, P(t-Bu)3

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

• yields but low enantiomeric excesses were obtained when cyclohexene and cyclopentene oxides were used as substrates (71% yield, 18% ee; 75% yield, 11% ee, respectively). Cyclooctene oxide was found to be poorly reactive with conversions of less than 10%. Conclusion This review demonstrates that

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

• reactions [95][97]. The first successful attempt was reported by Chung and Rhee, in which they showed the encapsulation of a bimetallic Pt–Pd catalyst in a highly branched PMAM-OH dendrimer corona [93]. These catalytic dendrimers were employed in partial hydrogenation of 1,3-cyclooctadiene into cyclooctene

Stimuli-responsive oligonucleotides in prodrug-based approaches for gene silencing

• Françoise Debart,
• Christelle Dupouy and
• Jean-Jacques Vasseur

Beilstein J. Org. Chem. 2018, 14, 436–469, doi:10.3762/bjoc.14.32

From betaines to anionic N-heterocyclic carbenes. Borane, gold, rhodium, and nickel complexes starting from an imidazoliumphenolate and its carbene tautomer

• Ming Liu,
• Jan C. Namyslo,
• Martin Nieger,
• Mika Polamo and
• Andreas Schmidt

Beilstein J. Org. Chem. 2016, 12, 2673–2681, doi:10.3762/bjoc.12.264

• oxidized to Rh(III). In order to balance the chemical equation, the formation of elemental hydrogen and of one equivalent of HCl can be postulated. Neither hydrogen nor reduced species such as cyclooctane or cyclooctene, however, have been detected. In the ESI mass spectra the base peak was detected at m/z

Recent advances in metathesis-derived polymers containing transition metals in the side chain

• Ileana Dragutan,
• Valerian Dragutan,
• Bogdan C. Simionescu,
• Albert Demonceau and
• Helmut Fischer

Beilstein J. Org. Chem. 2015, 11, 2747–2762, doi:10.3762/bjoc.11.296

• novel immobilized Rh catalytic system in which the metal is embedded, by means of the 5,5-dinorimido BINAP ligand, into the polymer, obtained from alternating ROMP of cyclooctene with the Grubbs first generation catalyst, has been disclosed in a patent by Bergens et al. [63]. This catalytic system

Synthesis of Xenia diterpenoids and related metabolites isolated from marine organisms

• Tatjana Huber,
• Lara Weisheit and
• Thomas Magauer

Beilstein J. Org. Chem. 2015, 11, 2521–2539, doi:10.3762/bjoc.11.273

• formation of the cyclooctene core was achieved via an acid-catalyzed cyclization to form tetrahydropyran 147. The following key sequence consisted of a thermal selenoxide 1,2-elimination to generate allyl vinyl ether 148 which underwent a stereoselective Claisen rearrangement [69] to furnish cyclooctenone