Particle size effect in the mechanically assisted synthesis of β-cyclodextrin mesitylene sulfonate

• Stéphane Menuel,
• Sébastien Saitzek,
• Eric Monflier and
• Frédéric Hapiot

Beilstein J. Org. Chem. 2020, 16, 2598–2606, doi:10.3762/bjoc.16.211

• beyond 270 min did not improve significantly the conversion as a plateau at ≈55% conversion was reached over time. Surprisingly, and contrary to what was commonly observed in the literature for solid-state addition reactions [25][26], it appeared that a reduction of the β-CD particle size slightly

Synthetic approaches to bowl-shaped π-conjugated sumanene and its congeners

• Shakeel Alvi and
• Rashid Ali

Beilstein J. Org. Chem. 2020, 16, 2212–2259, doi:10.3762/bjoc.16.186

• sensory material for selective recognition of cesium cations in water. In another event, Hirao’s group has prepared trioxosumanene 40 in the presence of RuCl3 and t-BuO2H which could be used as a key building block to generate diverse significant electroactive materials by virtue of nucleophilic addition

• reactions or by other means. After several experimentations, these workers were able to obtain trioxosumanene 40 in 73% yield (Scheme 7). More interestingly, monooxosumanene 38 was achieved selectively in good yield using phosphotungstic acid and t-BuO2H as shown in Scheme 7. To their surprise, they were

A complementary approach to conjugated N-acyliminium formation through photoredox-catalyzed intermolecular radical addition to allenamides and allencarbamates

• Olusesan K. Koleoso,
• Matthew Turner,
• Felix Plasser and
• Marc C. Kimber

Beilstein J. Org. Chem. 2020, 16, 1983–1990, doi:10.3762/bjoc.16.165

• innovative transformations, including cycloadditions [5][6][7][8][9], intramolecular cyclizations and intermolecular addition reactions [10][11][12][13][14][15][16][17][18], as well as the use of the allenamide building block in natural product synthesis [1]. Addition reactions of allenamides, which can also

Disposable cartridge concept for the on-demand synthesis of turbo Grignards, Knochel–Hauser amides, and magnesium alkoxides

• Mateo Berton,
• Kevin Sheehan,
• Andrea Adamo and
• D. Tyler McQuade

Beilstein J. Org. Chem. 2020, 16, 1343–1356, doi:10.3762/bjoc.16.115

• oxidative addition reactions is R–I > R–Br > R–Cl. To achieve the direct insertion of 2-chloropropane, the temperature was increased, and the best result was obtained at 80 °C, yielding iPrMgCl (0.78 M, 87%, Table S4, entry 7, Supporting Information File 1). Since iPrMgCl is more soluble in THF than the

Synthesis of 3-substituted isoxazolidin-4-ols using hydroboration–oxidation reactions of 4,5-unsubstituted 2,3-dihydroisoxazoles

• Lívia Dikošová,
• Júlia Laceková,
• Ondrej Záborský and
• Róbert Fischer

Beilstein J. Org. Chem. 2020, 16, 1313–1319, doi:10.3762/bjoc.16.112

• -unsubstituted 2,3-dihydroisoxazoles in moderate to very good yields, starting from readily available 5-acetoxy- and 5-hydroxyisoxazolidines [7][8]. Their reactivity in electrophilic addition reactions allows for a straightforward introduction of a hydroxy group at the C-4 position of the resulting

Copper-catalysed alkylation of heterocyclic acceptors with organometallic reagents

• Yafei Guo and
• Syuzanna R. Harutyunyan

Beilstein J. Org. Chem. 2020, 16, 1006–1021, doi:10.3762/bjoc.16.90

• enantioselective methods for the synthesis of these compounds resulting in high yield and enantioselectivity has proven challenging. As a result, significant effort has been invested into copper-catalysed asymmetric conjugate addition reactions using organometallics. In 2005, Feringa and co-workers reported on the

• enantioselectivity in addition reactions challenging. Nevertheless, Harutyunyan and co-workers introduced the first general catalytic methodology to access a wide variety of chiral piperidones in 2019, using Grignard reagents (Scheme 1C) [18]. Therein, a new catalytic system based on the ligand L4/Cu complex

• reagents and protecting groups were examined, providing the products with good yield (up to 90%) and ee (up to 95%). Copper-catalysed conjugate addition reactions to alkenyl-substituted heterocycles Chiral heterocyclic aromatic compounds are crucial motifs in natural products and bioactive molecules, and

Combining enyne metathesis with long-established organic transformations: a powerful strategy for the sustainable synthesis of bioactive molecules

• Valerian Dragutan,
• Ileana Dragutan,
• Albert Demonceau and
• Lionel Delaude

Beilstein J. Org. Chem. 2020, 16, 738–755, doi:10.3762/bjoc.16.68

• dihydrobenzofuranones. Ultimately, (−)-flueggine A and (+)-virosaine B were obtained by 1,3-dipolar addition reactions (Scheme 21). Virgidivarine and virgiboidine In 2013, Blechert et al. [91] devised an original methodology applying enyne metathesis as the key step for the total synthesis of virgidivarine (3-carboxy-N

Controlling alkyne reactivity by means of a copper-catalyzed radical reaction system for the synthesis of functionalized quaternary carbons

• Goki Hirata,
• Yu Yamane,
• Naoya Tsubaki,
• Reina Hara and
• Takashi Nishikata

Beilstein J. Org. Chem. 2020, 16, 502–508, doi:10.3762/bjoc.16.45

• ; Introduction Terminal alkynes are undoubtedly useful functional groups for organic synthesis, and they can undergo a variety of reactions [1]. The C–C triple bond of an alkyne is suitable for addition reactions, whereas the terminal hydrogen atom is a good target for cross-coupling by using Sonogashira and

Recent advances in photocatalyzed reactions using well-defined copper(I) complexes

• Mingbing Zhong,
• Xavier Pannecoucke,
• Philippe Jubault and
• Thomas Poisson

Beilstein J. Org. Chem. 2020, 16, 451–481, doi:10.3762/bjoc.16.42

• witnessed. 1.1 ATRA reactions Atom transfer radical addition reactions are linchpin transformations in organic synthesis as they allow an easy difunctionalization of alkenes. Usually, these reactions require the use of a radical initiator or thermal activation to initiate the radical chain. Recently

Architecture and synthesis of P,N-heterocyclic phosphine ligands

• Wisdom A. Munzeiwa,
• Bernard Omondi and
• Vincent O. Nyamori

Beilstein J. Org. Chem. 2020, 16, 362–383, doi:10.3762/bjoc.16.35

• N- and/or O-donor atoms [44]. During catalysis the weakly coordinating hard donor atom detaches to give way for the incoming substrate to coordinate to the metal center [45]. This behavior also aids in ligands being able to stabilize low-valent metal states and promote oxidative addition reactions

A review of asymmetric synthetic organic electrochemistry and electrocatalysis: concepts, applications, recent developments and future directions

• Munmun Ghosh,
• Valmik S. Shinde and
• Magnus Rueping

Beilstein J. Org. Chem. 2019, 15, 2710–2746, doi:10.3762/bjoc.15.264

• diastereoselective Michael addition reactions [103][104]. The glycine–nickel complex 184 was deprotonated using a radical anion generated from the electrochemical reduction of azobenzene. The anionic Ni complex 185 acted as a good C-nucleophile towards Michael acceptors 186 resulting in diastereoisomeric mixtures of

A new approach to silicon rhodamines by Suzuki–Miyaura coupling – scope and limitations

• Thines Kanagasundaram,
• Antje Timmermann,
• Carsten S. Kramer and
• Klaus Kopka

Beilstein J. Org. Chem. 2019, 15, 2569–2576, doi:10.3762/bjoc.15.250

• 30b to rhodamine 30c clearly outperforms the addition of lithiated 2-bromothiophene to xanthone 12 since 2-bromothiophene might also undergo lithiation in 5-position in competition to the halogen metal exchange (in general multiple halogenated aryls are problematic nucleophiles for these addition

• reactions). Conclusion Since just three literature examples are known to date in which Suzuki–Miyaura cross-coupling reactions gave access to silicon rhodamines in poor to moderate yields (Scheme 2), we wanted to improve these first valuable experimental results. In general, the amount of re-isolated

Fluorinated azobenzenes as supramolecular halogen-bonding building blocks

• Esther Nieland,
• Oliver Weingart and
• Bernd M. Schmidt

Beilstein J. Org. Chem. 2019, 15, 2013–2019, doi:10.3762/bjoc.15.197

• ][22][23][24]. Huber and co-workers demonstrated the activation of a carbonyl group by halogen bonding, and successfully applied this concept to catalysts for Michael addition reactions [25] and also employed neutral [26], and hypervalent iodolium derivatives as activators in a halide abstraction

Recent advances on the transition-metal-catalyzed synthesis of imidazopyridines: an updated coverage

• Gagandeep Kour Reen,
• Ashok Kumar and
• Pratibha Sharma

Beilstein J. Org. Chem. 2019, 15, 1612–1704, doi:10.3762/bjoc.15.165

• ) allow it to catalyze a number of organic reactions viz., nucleophilic substitutions, addition reactions, hydrogenations/hydrosilylations, cycloisomerizations, electrophilic aromatic substitutions, cross-coupling reactions, oxidative additions and reductive eliminations [66]. Iron–catalyzed C–H

• -2-carbaldehyde on the other hand resulted in appreciable yields under similar reaction conditions. The authors have successfully constructed a big library of 28 compounds with varying structure. In 2013, Gao et al. have exploited the TM-catalyzed nucleophilic addition reactions of haloalkynes 5

Synthesis of non-racemic 4-nitro-2-sulfonylbutan-1-ones via Ni(II)-catalyzed asymmetric Michael reaction of β-ketosulfones

• Alexander N. Reznikov,
• Anastasiya E. Sibiryakova,
• Marat R. Baimuratov,
• Eugene V. Golovin,
• Victor B. Rybakov and
• Yuri N. Klimochkin

Beilstein J. Org. Chem. 2019, 15, 1289–1297, doi:10.3762/bjoc.15.127

• acceptors and aldehydes [27][28][29][30][31][32], ketones [33], α-cyano esters [34][35], β-keto esters [35], β-keto acids [36], thiomalonates [37], nitroalkanes [38], oxindoles [39] and thiols [40] as Michael donors. There are only few examples of the use of sulfones as Michael donors in asymmetric addition

• reactions. Thus, ketonitrosulfones were obtained with good enantiomeric excesses via asymmetric addition of α-nitrosulfones to enones in the presence of organocatalysts [41]. Asymmetric addition of β-ketosulfones to nitroalkenes was implemented using various organocatalysts [42]. The reaction of

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

• located on the surface of the polymer are capable of various addition reactions (bromination, epoxidation, oxidation) forming films of several tens or hundreds of nanometers thick on the surface. However, no further penetration of reactants into the deeper polydicyclopentadiene layers occurs [28]. It is

Design and synthesis of C₃-symmetric molecules bearing propellane moieties via cyclotrimerization and a ring-closing metathesis sequence

• Sambasivarao Kotha,
• Saidulu Todeti and
• Vikas R. Aswar

Beilstein J. Org. Chem. 2018, 14, 2537–2544, doi:10.3762/bjoc.14.230

• ) reaction [11][12], and rearrangement of spiro-ketones, nucleophilic substitutions of alkenes, and photochemical addition reactions. Multicomponent reactions (MCRs) are also used for the synthesis of hetero-propellanes [13][14]. Recently, heterocyclic propellanes have been reviewed [15][16]. Our group also

Synthesis and post-functionalization of alternate-linked-meta-para-[2ⁿ.1ⁿ]thiacyclophanes

• Wout De Leger,
• Koen Adriaensen,
• Koen Robeyns,
• Luc Van Meervelt,
• Joice Thomas,
• Björn Meijers,
• Mario Smet and
• Wim Dehaen

Beilstein J. Org. Chem. 2018, 14, 2190–2197, doi:10.3762/bjoc.14.192

• -elimination (route B) can easily occur, leading to reversal of the addition reactions. This was observed in a stability experiment where pure [3 + 3] macrocycle 7 in CDCl3 (without adding base) over two weeks’ time converted into a mixture of [3 + 3] macrocycle 7 (9%), acyclic oligomers (50%) and the more

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

Asymmetric Michael addition reactions catalyzed by calix[4]thiourea cyclohexanediamine derivatives

• Zheng-Yi Li,
• Hong-Xiao Tong,
• Yuan Chen,
• Hong-Kui Su,
• Tangxin Xiao,
• Xiao-Qiang Sun and
• Leyong Wang

Beilstein J. Org. Chem. 2018, 14, 1901–1907, doi:10.3762/bjoc.14.164

• Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China 10.3762/bjoc.14.164 Abstract A number of upper rim-functionalized calix[4]thiourea cyclohexanediamine derivatives have been designed, synthesized and used as catalysts for enantioselective Michael addition reactions between

• , this may offer us the opportunity to improve the green aspect of many reactions both in organic and aqueous medium [30]. For example, it has been reported that calixarenes linked with thiourea groups can be used to catalyze asymmetric Aldol reactions or Michael addition reactions in recent years [31

• Michael addition reactions of acetylacetone and aromatic nitroalkenes. Results and Discussion Synthesis of catalysts The chemical structures and synthetic pathways for catalysts are shown in Scheme 1 and Scheme 2, respectively. A series of upper rim-functionalized calix[4]arene-based cyclohexanediamine

Three-component coupling of aryl iodides, allenes, and aldehydes catalyzed by a Co/Cr-hybrid catalyst

• Kimihiro Komeyama,
• Shunsuke Sakiyama,
• Kento Iwashita,
• Itaru Osaka and
• Ken Takaki

Beilstein J. Org. Chem. 2018, 14, 1413–1420, doi:10.3762/bjoc.14.118

• organolithium, organomagnesium, organozinc, and organochromium A, to facilitate addition reactions of appropriate carbon electrophiles such as aldehydes (Scheme 1, top) [1]. In contrast, π-electrophilic carbon-connected late transition metals B facilitate the carbometalation of carbon–carbon multiple bonds

Synthesis of chiral 3-substituted 3-amino-2-oxindoles through enantioselective catalytic nucleophilic additions to isatin imines

• Hélène Pellissier

Beilstein J. Org. Chem. 2018, 14, 1349–1369, doi:10.3762/bjoc.14.114

• nucleophiles, thus increasing the structural diversity of the resulting products. The first asymmetric catalytic versions were reported only in the 2010s despite tremendous achievements in catalytic asymmetric imine addition reactions [20][21][22]. Ever since, a number of catalytic asymmetric nucleophilic

Stereoselective nucleophilic addition reactions to cyclic N-acyliminium ions using the indirect cation pool method: Elucidation of stereoselectivity by spectroscopic conformational analysis and DFT calculations

• Koichi Mitsudo,
• Junya Yamamoto,
• Tomoya Akagi,
• Atsuhiro Yamashita,
• Masahiro Haisa,
• Kazuki Yoshioka,
• Hiroki Mandai,
• Koji Ueoka,
• Christian Hempel,
• Jun-ichi Yoshida and
• Seiji Suga

Beilstein J. Org. Chem. 2018, 14, 1192–1202, doi:10.3762/bjoc.14.100

Addition of dithi(ol)anylium tetrafluoroborates to α,β-unsaturated ketones

• Yu-Chieh Huang,
• An Nguyen,
• Simone Gräßle,
• Sylvia Vanderheiden,
• Nicole Jung and
• Stefan Bräse

Beilstein J. Org. Chem. 2018, 14, 515–522, doi:10.3762/bjoc.14.37

• at rt [33], reactions with 3e and 3g (R2 = iPr, Ph) required a reaction time of 13 h. As addition reactions of ketene dithioacetals bearing EWGs in α-position have been described earlier, we used the electrophile 3d for a comparison of those literature-known procedures with our experiments using non

Syn-selective silicon Mukaiyama-type aldol reactions of (pentafluoro-λ⁶-sulfanyl)acetic acid esters with aldehydes

• Anna-Lena Dreier,
• Andrej V. Matsnev,
• Joseph S. Thrasher and
• Günter Haufe

Beilstein J. Org. Chem. 2018, 14, 373–380, doi:10.3762/bjoc.14.25

• state A are the major products of the aldol addition reactions. As mentioned above, aldol addition products were not isolated from the reaction of 1 with electron rich p-methyl-, p-methoxy-, and p-ethoxybenzaldehydes. Here, aldol condensation products 4g–i were obtained as single isomers after

• conditions and application of enantiopure Lewis acids or SF5-substituted acetamides bearing a chiral auxiliary will result in asymmetric aldol addition reactions in the future. Conclusion From octyl SF5-acetate and TMSOTf/Et3N, a (Z)-enolate (ketene silylacetal) was preferentially formed as has already been