Switchable molecular tweezers: design and applications

• Pablo Msellem,
• Maksym Dekthiarenko,
• Nihal Hadj Seyd and
• Guillaume Vives

Beilstein J. Org. Chem. 2024, 20, 504–539, doi:10.3762/bjoc.20.45

• allosteric catalytic regulation (Figure 21). Mirkin and co-workers reported the symmetric tweezers 40 based on a Rh(I) complex with a phosphine and a labile thioether site and Cr(III)–salen arms as catalytic sites for the asymmetric ring opening of cyclohexene oxide by TMSN3 [80]. The closed tweezers showed

Rapid gas–liquid reaction in flow. Continuous synthesis and production of cyclohexene oxide

• Kyoko Mandai,
• Tetsuya Yamamoto,
• Hiroki Mandai and
• Aiichiro Nagaki

Beilstein J. Org. Chem. 2022, 18, 660–668, doi:10.3762/bjoc.18.67

• with good operational stability, evaluated by a constant high yield of cyclohexene oxide, to obtain the desired product with high productivity. Keywords: air; continuous flow; cyclohexene oxide; flow epoxidation; rapid gas–liquid reaction; Introduction From the past to the present, organic synthesis

• conventional batch technique has irreconcilable limitations. Cyclohexene oxide is one of the key starting materials for manufacturing various functional organic compounds and materials such as polymers and chiral organic compounds with cyclohexane moiety [2][3][4][5][6]. Thus, an efficient and fast synthetic

• method for the production of cyclohexene oxide is highly desired to be developed, taking sustainability for the environment and our society into consideration. The general synthetic procedure for cyclohexene oxide is the epoxidation of cyclohexene [7][8]. Among various oxidizing agents used in the

Recent advances in the syntheses of anthracene derivatives

• Giovanni S. Baviera and
• Paulo M. Donate

Beilstein J. Org. Chem. 2021, 17, 2028–2050, doi:10.3762/bjoc.17.131

• OMe, NO2, or Cl groups, and epoxides (149 and 150), DBU as catalyst, CTAB as surfactant, and water as solvent. The use of cyclohexene oxide (149) provided oxa-aza-benzo[a]anthracene derivatives 151 in excellent yields (90–96%). On the other hand, the use of styrene oxide (150) provided oxa-aza

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

α,γ-Dioxygenated amides via tandem Brook rearrangement/radical oxygenation reactions and their application to syntheses of γ-lactams

• Mikhail K. Klychnikov,
• Radek Pohl,
• Ivana Císařová and
• Ullrich Jahn

Beilstein J. Org. Chem. 2021, 17, 688–704, doi:10.3762/bjoc.17.58

• enantiomerically pure epoxides (S)-7b, (R)-7b, or (S)-7e (Table 2, entries 8–12) at 0 °C. The epoxide opening/Brook rearrangement steps were typically complete after an hour, except for cyclohexene oxide 7f for which the nucleophilic opening and Brook rearrangement steps took 24 h (Table 2, entry 13). Ferrocenium

• Information File 1 for details). The (R)-configuration at C2 as well as the (S)-configuration at both, C4 and the N-arylethyl group were established (Figure 2). A good diastereoselectivity was also observed for the ring-opening/Brook rearrangement/oxygenation sequence with cyclohexene oxide 7f, which

The charge-assisted hydrogen-bonded organic framework (CAHOF) self-assembled from the conjugated acid of tetrakis(4-aminophenyl)methane and 2,6-naphthalenedisulfonate as a new class of recyclable Brønsted acid catalysts

• Svetlana A. Kuznetsova,
• Alexander S. Gak,
• Yulia V. Nelyubina,
• Vladimir A. Larionov,
• Han Li,
• Michael North,
• Vladimir P. Zhereb,
• Alexander F. Smol'yakov,
• Artem O. Dmitrienko,
• Michael G. Medvedev,
• Igor S. Gerasimov,
• Ashot S. Saghyan and
• Yuri N. Belokon

Beilstein J. Org. Chem. 2020, 16, 1124–1134, doi:10.3762/bjoc.16.99

• alcohol 3 was unsuccessful (Table 1, run 15). Evidently, the catalytic properties of the CAHOF F-1 were superior to those of standard ion exchange materials under these reaction conditions. The CAHOF F-1 could also promote the ring opening of cyclohexene oxide (5) by alcohols (Scheme 3), with the

• partitioning of the epoxide into the aqueous phase was necessary for reaction to occur. Cyclohexene oxide (5) is, however, a good substrate under the same reaction conditions (Table 2, entry 5), possibly due to the greater reactivity of its fused bicyclic ring system. The Diels–Alder reaction of methyl vinyl

• in red. The synthesis of F-1. Uncrystallized F-1 or F-1 with an F-1a phase promoted the two- and three-phase reactions of styrene oxide (2). CAHOF F-1-promoted reactions of cyclohexene oxide (5) with alcohols and water. F-1-promoted Diels–Alder reaction. The ring opening of styrene oxide (2) by MeOH

Copolymerization of epoxides with cyclic anhydrides catalyzed by dinuclear cobalt complexes

• Yo Hiranoi and
• Koji Nakano

Beilstein J. Org. Chem. 2018, 14, 2779–2788, doi:10.3762/bjoc.14.255

•  2, entry 2). The copolymerization with cyclohexene oxide (CHO), a common alicyclic epoxide in epoxide/CA copolymerization, also gave the corresponding alternating copolymer (Table 2, entries 3 and 4). The TOF of 244 h−1 was achieved at 60 °C, which was the highest one ever reported for a CHO/PA

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

• , to varying levels of substitution and functionalization were tested using amines as nucleophiles, thiolysis was demonstrated with only two examples: using thiophenol as a nucleophile to open cyclohexene oxide (14) and benzyloxymethyloxirane (41, Scheme 10). Other than the mild reaction conditions

• acid catalyst for the asymmetric ring opening of cyclohexene oxide with alkyl- and arylthiols [37]. The optimal conditions were found to be 10 mol % of the catalyst relative to cyclohexene oxide, at room temperature, in dichloromethane as the solvent (Scheme 11). More polar solvents such as DMF

• retarded the reaction due to their tight coordination to the catalyst whilst non-polar solvents such as cyclohexane resulted in poor enantioselectivity probably due to coordination of the product β-hydroxy sulfide. The protocol was, however, limited to unsubstituted cyclohexene oxide, and as its greatest

Robust bifunctional aluminium–salen catalysts for the preparation of cyclic carbonates from carbon dioxide and epoxides

• Yuri A. Rulev,
• Zalina Gugkaeva,
• Victor I. Maleev,
• Michael North and
• Yuri N. Belokon

Beilstein J. Org. Chem. 2015, 11, 1614–1623, doi:10.3762/bjoc.11.176

• catalysts induced the formation of cyclic carbonates under mild reaction conditions (25–35 °C; 1–10 bar carbon dioxide pressure). However, with cyclohexene oxide under the same reaction conditions, the same catalysts induced the formation of polycarbonate. The catalysts could be recovered from the reaction

• volatility of the starting material under the reaction conditions. No cyclic carbonate was detected when cyclohexene oxide was used as substrate (Table 3, entries 1–5) and almost no conversion at all was detected in the reaction promoted by complex 1 (Table 3, entries 1 and 2). Catalyst 2 was more active and

• cyclic [32] or polycarbonate [33][34] from cyclohexene oxide, depending on the exact structure of the catalyst and cocatalyst. However, this is the first report of a one-component aluminium–salen-based catalyst for polycyclohexene carbonate synthesis. MALDI–TOF mass-spectra data (Figure 2) showed that

Surprisingly facile CO₂ insertion into cobalt alkoxide bonds: A theoretical investigation

• Willem K. Offermans,
• Claudia Bizzarri,
• Walter Leitner and
• Thomas E. Müller

Beilstein J. Org. Chem. 2015, 11, 1340–1351, doi:10.3762/bjoc.11.144

• cyclohexene oxide was the subject of a molecular orbital study on the tri-coordinated di-iminate zinc–alkoxide complex [(BDI)ZnOCH3], whereby BDI is N-(2,6-iPr2C6H3C(Me)-CHC(Me)-N-(2,6-iPr2C6H3) (see Figure 1) [33]. The study was based on the ONIOM [34][35] method, which is a computationally intricate method

• . A low activation barrier found for the CO2 insertion into the zinc–alkoxide bond may be related to the use of a relatively high energy unsaturated 16-electron complex. In the reaction mixture of neat cyclohexene oxide, the complex will readily coordinate additional cyclohexene oxide as solvent

Anion effect controlling the selectivity in the zinc-catalysed copolymerisation of CO₂ and cyclohexene oxide

• Sait Elmas,
• Muhammad Afzal Subhani,
• Walter Leitner and
• Thomas E. Müller

Beilstein J. Org. Chem. 2015, 11, 42–49, doi:10.3762/bjoc.11.7

• Chemie, RWTH Aachen University, Worringerweg 1, D-52074 Aachen, Germany 10.3762/bjoc.11.7 Abstract The choice of the anion has a surprisingly strong effect on the incorporation of CO2 into the polymer obtained during the zinc-catalysed copolymerisation of CO2 and cyclohexene oxide. The product span

• secondary amino and two phenoxy donor groups [17]. The binuclear Zn(II) complex ([LZn2X2], X = acetate) is substrate specific for the copolymerisation of CO2 and cyclohexene oxide [16]. Another established common structural motif is based on Salen-type ligands with a central Co(III) [18][19][20] or Cr(III

• the product selectivity and the activity of the complexes in catalysing the reaction of CO2 with cyclohexene oxide. Results and Discussion Synthesis and characterisation of binuclear [LZn2](X)2 complexes Complexes [LZn2]](CF3SO3)2 (1) and [LZn2](p-TSO3)2 (2) (Scheme 2) were prepared by reacting the

Copolymerization and terpolymerization of carbon dioxide/propylene oxide/phthalic anhydride using a (salen)Co(III) complex tethering four quaternary ammonium salts

• Jong Yeob Jeon,
• Seong Chan Eo,
• Jobi Kodiyan Varghese and
• Bun Yeoul Lee

Beilstein J. Org. Chem. 2014, 10, 1787–1795, doi:10.3762/bjoc.10.187

• applications. For example, the terpolymerization of CO2/PO/cyclohexene oxide (CHO) was successful, providing resins, of which the glass-transition temperatures (Tg) were modulated in the range of 50–100 °C according to the mole fraction of the incorporated CHO [24][25]. However, the feeding of a third monomer

Organocatalyzed enantioselective desymmetrization of aziridines and epoxides

• Ping-An Wang

Beilstein J. Org. Chem. 2013, 9, 1677–1695, doi:10.3762/bjoc.9.192

• yields and ee’s, but meso-cyclohexene oxide resulted in a racemic product under the optimal conditions. Because of the low catalytic activities of axially-chiral pyridine N-oxides OC-83 or OC-84 in the desymmetrization process, a hexacoordinate silicate intermediate between SiCl4 and chiral bipyridine N

• PINDOX OC-98 for the enantioselective ring-opening of cyclic meso-epoxides with SiCl4 to produce chlorohydrins in moderate to good enantiomeric excess (Scheme 21). The stereoselectivities are very sensitive to the ring size of the cyclic oxides. For example, when cyclohexene oxide was used as a substrate

Prins fluorination cyclisations: Preparation of 4-fluoro-pyran and -piperidine heterocycles

• Guillaume G. Launay,
• Alexandra M. Z. Slawin and
• David O'Hagan

Beilstein J. Org. Chem. 2010, 6, No. 41, doi:10.3762/bjoc.6.41

• using 2-vinylcyclohexan-ol (8) as a substrate. Vinylcyclohexanol 8 was prepared by treatment of cyclohexene oxide (10) with vinylmagnesium bromide in the presence of CuBr/DMSO as illustrated in Table 4 [24]. This gave a single diastereoisomer of 8 which was used in the Prins fluorination reactions

The development and evaluation of a continuous flow process for the lipase- mediated oxidation of alkenes

• Charlotte Wiles,
• Marcus J. Hammond and
• Paul Watts

Beilstein J. Org. Chem. 2009, 5, No. 27, doi:10.3762/bjoc.5.27

• consistent with that reported within the literature [39]. 1,2-Epoxycyclohexane (cyclohexene oxide) A pre-mixed solution of cyclohexene (10, 0.1 M) and 30% H2O2 (2, 0.2 M) was pumped through the packed-bed reactor at a flow rate of 5 μl min−1 and a reaction temperature of 70 °C for a period of 24 h. The