Non-covalent organocatalyzed enantioselective cyclization reactions of α,β-unsaturated imines

• Sergio Torres-Oya and
• Mercedes Zurro

Beilstein J. Org. Chem. 2024, 20, 3221–3255, doi:10.3762/bjoc.20.268

• the field, other dienes bearing two nitrogen atoms in their structure such as 1,3-azadienes or azo-alkenes are also included. On the contrary, asymmetric cyclizations involving aza-ortho-quinone intermediates and in situ-formed 1-azadienes were excluded as they have been discussed in other recent

Direct trifluoroethylation of carbonyl sulfoxonium ylides using hypervalent iodine compounds

• Radell Echemendía,
• Carlee A. Montgomery,
• Fabio Cuzzucoli,
• Antonio C. B. Burtoloso and
• Graham K. Murphy

Beilstein J. Org. Chem. 2024, 20, 3182–3190, doi:10.3762/bjoc.20.263

• versatile intermediates in organic synthesis due to their unique reactivity and ability to participate in a wide range of chemical transformations. In this scenario, sulfoxonium ylides are excellent substrates for bifunctionalization reactions, due to the ambiphilic character in their ylidic carbon [16

• met convergence criteria. Consistent with the PES scan outcome, the NEB-CI approach also indicated that the SN2 mechanistic proposal (Figure 2, path 2) dominates. Finally, for both mechanistic pathways, all intermediates and transition states were subjected to optimization and frequency calculations

Multicomponent reactions driving the discovery and optimization of agents targeting central nervous system pathologies

• Lucía Campos-Prieto,
• Aitor García-Rey,
• Eddy Sotelo and
• Ana Mallo-Abreu

Beilstein J. Org. Chem. 2024, 20, 3151–3173, doi:10.3762/bjoc.20.261

• obtained intermediates with the appropriate commercial lactams, under microwave irradiation (Scheme 8). As a result, compound 8a has been identified as a promising derivative potentially useful in further AD drug discovery for its antioxidant activity (4.7 TE in ORAC-FL assay), moderate hAChE inhibition

• build the principal heterocycle of the compounds. Good reaction yields (70–87%) made it possible to obtain the aminothiophene carboxylates necessary for the following steps of the route [52]. Some of the intermediates of the Gewald reaction were oxidized to provide further exploration of the

Controlled oligomerization of [1.1.1]propellane through radical polarity matching: selective synthesis of SF₅- and CF₃SF₄-containing [2]staffanes

• Jón Atiba Buldt,
• Wang-Yeuk Kong,
• Yannick Kraemer,
• Masiel M. Belsuzarri,
• Ansh Hiten Patel,
• James C. Fettinger,
• Dean J. Tantillo and
• Cody Ross Pitts

Beilstein J. Org. Chem. 2024, 20, 3134–3143, doi:10.3762/bjoc.20.259

• becomes more negative (or less positive) the farther it is from either the SF5 or CF3SF4 substituent, consistent with the notion that it becomes more nucleophilic. Moreover, the Δq is largest between the first two intermediates in both series – INT1 vs INT2 and INT3 vs INT4 – indicating that the most

• synthetic and computational study demonstrates that selective one-pot syntheses of [2]staffanes can be achieved when employing reagents that serve as radical sources of "extreme" electron-withdrawing groups (e.g., SF5 or CF3SF4), which impact relative philicities of the bicyclopentyl radical intermediates

Hypervalent iodine-mediated intramolecular alkene halocyclisation

• Charu Bansal,
• Oliver Ruggles,
• Albert C. Rowett and
• Alastair J. J. Lennox

Beilstein J. Org. Chem. 2024, 20, 3113–3133, doi:10.3762/bjoc.20.258

• pyrrolidine intermediates A can undergo further transformations (Scheme 10), depending on their structure and the iodane reagent being used. For example, higher yields of 3-fluoropiperidine products 6 were observed when using cyclic iodane reagents 21 and 22 (Scheme 10), which was suggested to be because a

Advances in the use of metal-free tetrapyrrolic macrocycles as catalysts

• Mandeep K. Chahal

Beilstein J. Org. Chem. 2024, 20, 3085–3112, doi:10.3762/bjoc.20.257

• reversible formation of covalent enamine intermediates, it also leveraged the supramolecular behavior of the porphyrinic component. In acidic aqueous media, the porphyrin macrocycle formed supramolecular H- and J-aggregates stabilized by hydrophobic interactions between the π-systems of the aromatic regions

• porphyrin radical anion. Ultimately, protonation of intermediate E led to the final product. Formation of intermediates, such as enamine A and cation radical B, was confirmed using techniques like ESIMS, 1H NMR, and EPR, Stern–Volmer quenching experiments, respectively. All these mechanistic studies

Synthesis of the 1,5-disubstituted tetrazole-methanesulfonylindole hybrid system via high-order multicomponent reaction

• Cesia M. Aguilar-Morales,
• América A. Frías-López,
• Nadia V. Emilio-Velázquez,
• Alejandro Islas-Jácome,
• Angelica Judith Granados-López,
• Jorge Gustavo Araujo-Huitrado,
• Yamilé López-Hernández,
• Hiram Hernández-López,
• Luis Chacón-García,
• Jesús Adrián López and
• Carlos J. Cortés-García

Beilstein J. Org. Chem. 2024, 20, 3077–3084, doi:10.3762/bjoc.20.256

• of the 1,5-disubstituted tetrazole-alkyne intermediates was unnecessary; we previously reported this heterocyclic system [24][25][26]. The heteroannulation reaction was then investigated under the most common conditions, utilizing a catalytic system comprising PdCl2(PPh3)2, Et3N and CuI [23][28

Enantioselective regiospecific addition of propargyltrichlorosilane to aldehydes catalyzed by biisoquinoline N,N’-dioxide

• Noble Brako,
• Sreerag Moorkkannur Narayanan,
• Amber Burns,
• Layla Auter,
• Valentino Cesiliano,
• Rajeev Prabhakar and
• Norito Takenaka

Beilstein J. Org. Chem. 2024, 20, 3069–3076, doi:10.3762/bjoc.20.255

• enantioenriched form [11][12]. However, such metal/metalloid reagents and the corresponding metal catalyst-bound intermediates often equilibrate between possible regioisomeric forms and can undergo both, SE2 and SE2’ addition reactions, resulting in a mixture of homopropargylic alcohols and α-allenic alcohols [14

• ][15][16][17][18][19], the separation of which is by no means trivial [20] (Scheme 1). Nonetheless, substituents at the carbon atom indicated by γ (R2) of these reagents have been shown to bias the metallotropic rearrangement and/or the kinetic reactivity of the competing regioisomeric intermediates

• exergonic from Rprop. These results show that the presence of N,N-diisopropylethylamine as base makes this process more energetically feasible by substantially stabilizing the transition states and intermediates in the pathway. These results are strongly supported by the experimental data. In a previous

Chemical structure metagenomics of microbial natural products: surveying nonribosomal peptides and beyond

• Thomas Ma and
• John Chu

Beilstein J. Org. Chem. 2024, 20, 3050–3060, doi:10.3762/bjoc.20.253

• the glycopeptide antibiotic family [62][63]. Their aromatic rings undergo oxidative coupling to form biaryl moieties that restrict atropisomerism; the resulting rigid structure is key to their high affinity binding to peptidoglycan intermediates [64][65]. Glycopeptide antibiotics include vancomycin

Tailored charge-neutral self-assembled L₂Zn₂ container for taming oxalate

• David Ocklenburg and
• David Van Craen

Beilstein J. Org. Chem. 2024, 20, 3007–3015, doi:10.3762/bjoc.20.250

• ; metallocontainer; oxalate; Introduction Dicarboxylic acids and their corresponding anions are essential intermediates in the biosynthesis of proteins and important biological metabolites [1][2]. As a result, the development of receptors for this class of compounds is of high interest [3][4][5]. Oxalate, the

Advances in radical peroxidation with hydroperoxides

• Oleg V. Bityukov,
• Pavel Yu. Serdyuchenko,
• Andrey S. Kirillov,
• Gennady I. Nikishin,
• Vera A. Vil’ and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2024, 20, 2959–3006, doi:10.3762/bjoc.20.249

• involving radical intermediates from hydroperoxides under redox conditions (Scheme 3). The reactivity of O-centered radicals is less predictable and more diverse depending on radical structure and substrate pattern than the chemistry of C-centered radicals [29][30]. Generally, peroxy radicals have a

• partners in the difunctionalization of alkenes 169 and 172 with hydroperoxides, respectively (Scheme 53a and Scheme 53b). According to the authors [121], the key intermediates are the Co(III)OO-t-Bu and the CF3 radicals, which are generated from Co(OAc)2 and CF3SO2Na in the presence of TBHP. In the case of

• intermediates (tert-butylperoxy radical or Mn(III)(OAc)2OO-t-Bu) can occur via oxidation of TBHP with Mn(OAc)3 or via ligand exchange between acetate and TBHP. The Mn(OAc)3 is regenerated by oxidation of Mn(OAc)2 with TBHP. The tert-butylperoxy radical reacts with styrene 194 to give the stabilized benzyl

Recent advances in transition-metal-free arylation reactions involving hypervalent iodine salts

• Ritu Mamgain,
• Kokila Sakthivel and
• Fateh V. Singh

Beilstein J. Org. Chem. 2024, 20, 2891–2920, doi:10.3762/bjoc.20.243

• presence of fluorine and a newly installed electron-deficient aryl group on α-carbon which increases electrophilicity of the α-carbon center [55]. The proposed reaction mechanism (Scheme 2) begins with the formation of one of two potential iodine intermediates, labeled as I or II. These intermediates arise

• upon binding of the enolate molecule to iodine either through a carbon–iodine or an oxygen–iodine bond. Both intermediates, I and II, are in rapid equilibrium with each other and further undergo two different types of reactions: [1,2]-ligand coupling and [2,3]-rearrangement (Scheme 2). Either of these

• base-mediated deprotonation of substrates 86 produces the corresponding ester enolate. This enolate undergoes a retro-Michael reaction, generating sulfenate anion A. The sulfenate anion A then nucleophilically attacks the diaryliodonium salts 16, forming hypervalent iodine intermediates B. Finally

Synthesis of tricarbonylated propargylamine and conversion to 2,5-disubstituted oxazole-4-carboxylates

• Kento Iwai,
• Akari Hikasa,
• Kotaro Yoshioka,
• Shinki Tani,
• Kazuto Umezu and
• Nagatoshi Nishiwaki

Beilstein J. Org. Chem. 2024, 20, 2827–2833, doi:10.3762/bjoc.20.238

• biologically active compounds [27][28][29][30][31] and their synthetic intermediates [32][33][34][35][36]. Thus, this method, which enables modification at the 2- and 5-positions of oxazole-4-carboxylates, is a valuable tool for the study of these compounds. Experimental General All reagents except for DEMO

Synthesis and antimycotic activity of new derivatives of imidazo[1,2-a]pyrimidines

• Dmitriy Yu. Vandyshev,
• Daria A. Mangusheva,
• Khidmet S. Shikhaliev,
• Kirill A. Scherbakov,
• Oleg N. Burov,
• Alexander D. Zagrebaev,
• Tatiana N. Khmelevskaya,
• Alexey S. Trenin and
• Fedor I. Zubkov

Beilstein J. Org. Chem. 2024, 20, 2806–2817, doi:10.3762/bjoc.20.236

• conversion of the reagents was not achieved until after 12 h of boiling, and the yield of the product varied in the range of 25–35% (entries 1 and 2, Table 1). In the cases of DMF and MeCN, the formation of complex, inseparable mixtures of numerous intermediates and products of their subsequent

• polyfunctional precursors 1, 2, and 3, two pathways are theoretically possible (Scheme 2 and Scheme 3). The first one involves the N-nucleophilic Michael addition to the activated multiple bond of the imide, leading to the formation of linear intermediates 6 or 8 (pathways A1 and B1) at the expense of the endo

• -nitrogen atom. The second route involves the participation of an amino group which allows the formation of adducts 7 and 9 (routes A2 and B2). The intermediates formed then undergo subsequent tandem recyclization of succinimide/citraconimide fragments at the expense of one of the carbonyl groups and the

Mechanochemical difluoromethylations of ketones

• Jinbo Ke,
• Pit van Bonn and
• Carsten Bolm

Beilstein J. Org. Chem. 2024, 20, 2799–2805, doi:10.3762/bjoc.20.235

• through the formation of novel reactive intermediates [15][16][17][18]. Fluorine-containing functional groups are essential structural motifs in the development of new bioactive compounds and functional materials. Compared to their non-fluorinated analogs, the presence of fluorine atoms in molecular

Copper-catalyzed yne-allylic substitutions: concept and recent developments

• Shuang Yang and
• Xinqiang Fang

Beilstein J. Org. Chem. 2024, 20, 2739–2775, doi:10.3762/bjoc.20.232

• expand the scope of transition metal-catalyzed substitution reactions. Since its discovery in 2022, copper-catalyzed yne-allylic substitution has undergone rapid development and significant progress has been made using the key copper vinyl allenylidene intermediates. This review summarizes the

Synthesis of spiroindolenines through a one-pot multistep process mediated by visible light

• Francesco Gambuti,
• Jacopo Pizzorno,
• Chiara Lambruschini,
• Renata Riva and
• Lisa Moni

Beilstein J. Org. Chem. 2024, 20, 2722–2731, doi:10.3762/bjoc.20.230

• materials (Scheme 1d). The synthetic procedure is achieved using blue light irradiation and bromotrichloromethane (BrCCl3), as a one-pot procedure, minimizing chemical wastes, avoiding purification of intermediates, and simplifying practical aspects. Results and Discussion We have recently published the one

• argon atmosphere to prevent the interaction of oxygen or reactive oxygen intermediates, which are not always compatible with the substrates, as well as the key intermediates. Moreover, BrCCl3 and its reduced form (chloroform) can be easily removed from the reaction mixture thanks to their low boiling

• and the intermediates involved, the relationship between the product conversions and the reaction time was investigated in the reaction between N-Ph-THIQ, 3,5-dimethoxyaniline and t-BuNC in the presence of BrCCl3 under light irradiation (Figure 2). This time profile shows that, as soon as the N-Ph

5th International Symposium on Synthesis and Catalysis (ISySyCat2023)

• Anthony J. Burke and
• Elisabete P. Carreiro

Beilstein J. Org. Chem. 2024, 20, 2704–2707, doi:10.3762/bjoc.20.227

• imidazolium ring formation. The resulting carbene was metalated at the C2 position with Au(I), Cu(I), and Ir(I), obtaining an L-shaped NHC ligand scaffold. Līpiņš et al. introduced a new method for synthesizing 4-azido-6,7-dimethoxy-2-alkyl/arylsulfonylquinazolines, which are key intermediates in the

A review of recent advances in electrochemical and photoelectrochemical late-stage functionalization classified by anodic oxidation, cathodic reduction, and paired electrolysis

• Nian Li,
• Ruzal Sitdikov,
• Ajit Prabhakar Kale,
• Joost Steverlynck,
• Bo Li and
• Magnus Rueping

Beilstein J. Org. Chem. 2024, 20, 2500–2566, doi:10.3762/bjoc.20.214

• product (Scheme 15). The synthesis of aziridines can be achieved via the formation of nitrenes in either a metal-catalyzed or metal-free fashion. In this context, Wickens and colleagues presented a remarkable dication pool strategy for accessing N-alkylaziridines via metastable dicationic intermediates

• cross-coupling between these two intermediates, followed by intramolecular cyclization and subsequent deprotonation results in the desired product (Scheme 20). Furthermore, Budny and coworkers demonstrated that (±)-triticonazole and related compounds could be cyclized and alkoxylated to the

HFIP as a versatile solvent in resorcin[n]arene synthesis

• Hormoz Khosravi,
• Valeria Stevens and
• Raúl Hernández Sánchez

Beilstein J. Org. Chem. 2024, 20, 2469–2475, doi:10.3762/bjoc.20.211

• limitation, we analyzed the mechanism underlying the formation of resorcin[n]arenes. The first step of the cyclization reaction is a hydroxyalkylation involving various cationic intermediates [69]. Hence, we hypothesized that any factor enhancing the rate of the first step by stabilizing carbocations will

Photoredox-catalyzed intramolecular nucleophilic amidation of alkenes with β-lactams

• Valentina Giraldi,
• Giandomenico Magagnano,
• Daria Giacomini,
• Pier Giorgio Cozzi and
• Andrea Gualandi

Beilstein J. Org. Chem. 2024, 20, 2461–2468, doi:10.3762/bjoc.20.210

• -centered radicals, such as aminyl, amidyl, or iminyl radicals, N-heterocyclic amidyl radicals were largely underinvestigated despite their importance as intermediates or relevant N-heterocyclic products in medicinal chemistry [7][8][9][10]. Recently, photoredox catalysis has emerged as a novel area of

• thiophenolate. Conclusion To conclude, we have employed a photoredox methodology to access clavam and pyrrolyloxazole intermediates, showing the possibility of using the nucleophilic nitrogen atom of β-lactams under photoredox conditions. The acridinium catalyst IV was able to oxidize the C=C double bond

Hypervalent iodine-mediated cyclization of bishomoallylamides to prolinols

• Smaher E. Butt,
• Konrad Kepski,
• Jean-Marc Sotiropoulos and
• Wesley J. Moran

Beilstein J. Org. Chem. 2024, 20, 2455–2460, doi:10.3762/bjoc.20.209

• Gauntlett for assistance with synthesis of some intermediates. Funding This study was supported by an EPSRC Doctoral Training Partnership (grant number EP/T51813X/1) held at the University of Huddersfield (K.K.), a University of Huddersfield funded Ph.D. studentship (S.B.), and by the Université de Pau et

Synthesis and conformational analysis of pyran inter-halide analogues of ᴅ-talose

• Olivier Lessard,
• Mathilde Grosset-Magagne,
• Paul A. Johnson and
• Denis Giguère

Beilstein J. Org. Chem. 2024, 20, 2442–2454, doi:10.3762/bjoc.20.208

• approach from levoglucosan 1 (Figure 1a) [23]. Allopyranose inter-halides 4 incorporating the 2,3-cis, 3,4-cis relationship for the halogens were prepared via intermediates 2 and 3 from levoglucosan (1). Compounds 4 were the starting point to complex 2,3,4-trihalohexanetriols and 2,3,4,5

• 1,6-anhydro-2,3-dideoxy-2,3-difluoro-β-ᴅ-mannopyranose (5) readily accessible form levoglucosan (1, Scheme 1) [24]. Activation of the C4 hydroxy group as triflate and direct treatment with a nucleophilic halogen furnished intermediates 8–11. The latter compounds proved to be difficult to purify

Efficient one-step synthesis of diarylacetic acids by electrochemical direct carboxylation of diarylmethanol compounds in DMSO

• Hisanori Senboku and
• Mizuki Hayama

Beilstein J. Org. Chem. 2024, 20, 2392–2400, doi:10.3762/bjoc.20.203

• intermediates at the anode. The produced acetate ion D and a magnesium ion form the salt E, which upon acid treatment during workup gives a diphenylacetic acid 2. The effects of DMSO as solvent are not clear at present, and one reasonable and acceptable aspect might be the solubility of the salt of intermediate

Asymmetric organocatalytic synthesis of chiral homoallylic amines

• Nikolay S. Kondratyev and
• Andrei V. Malkov

Beilstein J. Org. Chem. 2024, 20, 2349–2377, doi:10.3762/bjoc.20.201

• process and the rich toolkit of advanced organic synthesis [5]. Homoallylic amines occupy a significant niche in alkaloid synthesis as they frequently appear as key intermediates in syntheses of the various nitrogen-containing natural products [6][7][8][9][10][11][12][13][14]. Additionally, they can be

• , that the 2-aminophenol functionality in the substrates is a prerequisite for attaining high enantioselectivity in the allylation. Interestingly, the aldimines synthesised from 2-hydroxy-4-methylaniline produced inferior yields. While the N-aryl homoallylic amines 66 can be useful intermediates in total

• release catalyst 78 completing the catalytic cycle (Scheme 17). In a mechanistic probe, the proposed reaction intermediates were used as starting electrophiles under the standard reaction conditions (Scheme 18). In all three cases, identical outcomes were achieved, supporting the proposed catalytic cycle