The effect of neighbouring group participation and possible long range remote group participation in O-glycosylation

• Rituparna Das and
• Balaram Mukhopadhyay

Beilstein J. Org. Chem. 2025, 21, 369–406, doi:10.3762/bjoc.21.27

Synthesis of disulfides and 3-sulfenylchromones from sodium sulfinates catalyzed by TBAI

• Zhenlei Zhang,
• Ying Wang,
• Xingxing Pan,
• Manqi Zhang,
• Wei Zhao,
• Meng Li and
• Hao Zhang

Beilstein J. Org. Chem. 2025, 21, 253–261, doi:10.3762/bjoc.21.17

• tetrabutylammonium iodide (TBAI)/H2SO4 reduction system using sodium sulfinate as key component, thus eliminating the need for thiols and redox reagents commonly used in traditional methods. Various disulfides and 3-sulfenylchromones were obtained in moderate to excellent yields through this methodology. Mechanistic

• studies indicate that thiosulfonates play an important role in the reaction process. Keywords: disulfides; sodium sulfinates; 3-sulfenylchromones; TBAI; thiosulfonates; Introduction Organosulfur compounds containing S–S bonds, often referred to as disulfides, are among the most valuable functional

Visible-light-promoted radical cyclisation of unactivated alkenes in benzimidazoles: synthesis of difluoromethyl- and aryldifluoromethyl-substituted polycyclic imidazoles

• Yujun Pang,
• Jinglan Yan,
• Nawaf Al-Maharik,
• Qian Zhang,
• Zeguo Fang and
• Dong Li

Beilstein J. Org. Chem. 2025, 21, 234–241, doi:10.3762/bjoc.21.15

• target products in good to excellent yields. Mechanistic studies revealed that the reaction proceeds via a radical pathway. Keywords: cyclization; difluoromethylation; hypervalent iodine; polycyclic imidazole; visible light; Introduction Organofluorine compounds continue to play important roles in

Recent advances in electrochemical copper catalysis for modern organic synthesis

• Yemin Kim and
• Won Jun Jang

Beilstein J. Org. Chem. 2025, 21, 155–178, doi:10.3762/bjoc.21.9

• , and benzamide, however, no relevant competitive oxidation peak was observed with only Cu(OAc)2. These results indicate that Cu(II) intermediate 5 was generated. Based on the mechanistic studies, the authors suggested plausible reaction mechanisms (Figure 4). First, the Cu(II) catalyst coordinates with

• product 36. Finally, using 1-naphthyl ester and relatively bulkier 2,6-dimethylhydroqunone as starting materials produced chiral 1,6-addition products 37. In mechanistic studies, using quinone 38 instead of hydroquinone 34 in the electrochemical-free process produced the desired product 36, with a similar

• standard Cu-catalyzed electrochemical protocol. Based on mechanistic studies, the proposed mechanism is shown in Figure 9. First, hydroquinone 34 is oxidized at the anode to generate a quinone intermediate 38. Meanwhile, the chiral copper catalyst reacts with the Schiff base 33, generating a nucleophilic

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

• excellent enantioselectivities (70–95% ee) when using chiral phosphoric acid XIV (Scheme 16). Mechanistic studies were performed to unveil whether a concerted or stepwise mechanism is taking place, such as trying to trap a possible iminium ion intermediate. The outcome of those experiments pointed towards a

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

• . The level of this chemoselectivity was dependent on the iodane ligand: OPiv was more selective for aminofluorination than OAc, which was proposed to be due to differences in basicity and nucleophilicity (Scheme 10). Detailed mechanistic studies were carried out using multinuclear NMR spectroscopy

• diastereoselectivity in aminofluorination competing with carboxyfluorination products. Mechanistic studies of the fluoroamination of acyclic substrates showing the competing carboxyfluorination products. AIF = aziridinium ion formation, AIO = aziridinium ion opening, RLC = reductive ligand coupling. Fluorocyclisation

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

• 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

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

• offloading step always entails the same chemical reaction, wherein nucleophilic attack is promoted by the catalytic triad of a TE via general base catalysis. This is likely why traditional mechanistic studies that focused on the enzyme active site failed to work out how TEs control NRP topology. A priori

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

• aromatic rings were investigated, and based on the obtained yields of the products it was concluded that the reaction is compatible with electron-donating, electron-withdrawing, and electron-neutral substitutions. Mechanistic studies, including a cross-over reaction, indicated that the aryl migration is

C–H Trifluoromethylthiolation of aldehyde hydrazones

• Victor Levet,
• Balu Ramesh,
• Congyang Wang and
• Tatiana Besset

Beilstein J. Org. Chem. 2024, 20, 2883–2890, doi:10.3762/bjoc.20.242

• -trifluoroacetophenone as an internal standard. ND = not detected. Optimization of the reaction conditions.a Supporting Information Supporting Information File 28: Full experimental procedures, characterization of products, details of mechanistic studies, and spectral data. Funding This work has been partially

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

• isolating the low-boiling non-polar products. Mechanistic studies suggested that in situ-generated difluorocarbene reacts with the ketone oxygen, followed by intermolecular protonation/deprotonation. Although the process has still synthetic limitations, also acyclic ketones can now be converted into

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

• rise to a series of differently substituted 1,4-enynes with monofluoroalkyl units in high yields and ee values (Scheme 18, 18a–i). The reaction effectively overcomes the drawbacks of low activity of tertiary carbon nucleophiles and instability of fluorinated compounds. Preliminary mechanistic studies

• vinyl allenylidene species. A series of differently substituted spiro-cyclic products can be obtained with high yields, regio- and stereoselectivities (Scheme 32, 30a–x). Preliminary mechanistic studies indicated that the reaction first undergoes a substitution at the α-position of yne-allylic ester

• ). Preliminary mechanistic studies have ruled out the 1,3-sigmatropic shift, indicating that the reaction proceeds through a nucleophilic substitution–annulation process of a reactive π-extended copper-allenylidene intermediate (Scheme 43). At the same time, Qi and Xu et al. [79] also realized the dearomative

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

• further emphasized its utility. Mechanistic studies have demonstrated that the key to this selective chemical conversion lies in the dual oxidation process at the anode. The authors suggest that anodic oxidation of the sulfide generates a sulfur radical cation intermediate, which reacts with water at the

• ]. This mild method proceeds with a broad range of unactivated alkenes, including natural products and pharmaceutical derivatives such as sulbactam acid and oxaprozin. Mechanistic studies revealed that the reaction was initiated by the electrochemical oxidation of iodide ions, generating iodine radicals

• group. Based on extensive mechanistic studies, they proposed the formation of a formal Ni(IV) complex during the process. Remarkably, nickel proved to be uniquely effective for this protocol, as other transition-metal catalysts based on Cu, Co, Pd, Ir, Ru, and Rh did not catalyze the reaction (Scheme 36

Catalysing (organo-)catalysis: Trends in the application of machine learning to enantioselective organocatalysis

• Stefan P. Schmid,
• Leon Schlosser,
• Frank Glorius and
• Kjell Jorner

Beilstein J. Org. Chem. 2024, 20, 2280–2304, doi:10.3762/bjoc.20.196

Multicomponent syntheses of pyrazoles via (3 + 2)-cyclocondensation and (3 + 2)-cycloaddition key steps

• Ignaz Betcke,
• Alissa C. Götzinger,
• Maryna M. Kornet and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2024, 20, 2024–2077, doi:10.3762/bjoc.20.178

• position 1. This protocol involves the utilization of enaminones, hydrazine, and various aryl halides as substrates, resulting in the formation of 1,3-substituted pyrazoles 76 (Scheme 27) [105]. Mechanistic studies have indicated that in this domino reaction, the initial formation of 3-substituted

1,2-Difluoroethylene (HFO-1132): synthesis and chemistry

• Liubov V. Sokolenko,
• Taras M. Sokolenko and
• Yurii L. Yagupolskii

Beilstein J. Org. Chem. 2024, 20, 1955–1966, doi:10.3762/bjoc.20.171

• the methods for the preparation of HFO-1132 as well as reactions demonstrating the chemical behavior of this compound. From the reactions not included in this Review article, mechanistic studies on 1,2-difluoroethylene ozonolysis [77][103][104][105][106][107][108] and studies on the stability of

Electrochemical radical cation aza-Wacker cyclizations

• Sota Adachi and
• Yohei Okada

Beilstein J. Org. Chem. 2024, 20, 1900–1905, doi:10.3762/bjoc.20.165

• reactions rather than ionic ones, since five-membered pyrrolidine formation is preferred over six-membered piperidine formation. Further mechanistic studies of the electrochemical radical cation aza-Wacker cyclizations are underway in our laboratory. Experimental Electrochemical aza-Wacker cyclizations: The

• mmol), Bu4NOTf (0.1 M), TFA (1 equiv), CH3CN (0.4 mL), and 1,2-DCE (3.6 mL). Yields reported here are isolated yields. Mechanistic studies of aza-Wacker cyclization. A: Electrochemical (Bu4NOTf in CH3CN/1,2-DCE), B: non-electrochemical (LiClO4 in CH3NO2). Control studies for electrochemical aza-Wacker

Electrophotochemical metal-catalyzed synthesis of alkylnitriles from simple aliphatic carboxylic acids

• Yukang Wang,
• Yan Yao and
• Niankai Fu

Beilstein J. Org. Chem. 2024, 20, 1497–1503, doi:10.3762/bjoc.20.133

• , in an undivided cell, at 2.3 V cell potential, 400 nm LEDs, for 12 hours. a2,4,6-Collidine (1.0 equiv) was used instead of BTMG. bPhen was used instead of BPhen. cDMF/CH3CN (1:15 v/v) was used as solvent. dReactions were run with 0.4 mmol LiClO4 instead of TBABF4. Mechanistic studies and proposed

• catalytic cycles. Reaction discovery and optimization.a Supporting Information Supporting Information File 18: Experimental procedures, mechanistic studies, analytical data and copies of NMR spectra. Funding We thank the National Natural Science Foundation of China (No. 22071252) and the Chinese Academy

Manganese-catalyzed C–C and C–N bond formation with alcohols via borrowing hydrogen or hydrogen auto-transfer

• Mohd Farhan Ansari,
• Atul Kumar Maurya,
• Abhishek Kumar and
• Saravanakumar Elangovan

Beilstein J. Org. Chem. 2024, 20, 1111–1166, doi:10.3762/bjoc.20.98

• 110 °C for 16 h), moderate to good yields of N-methylamines were produced (Scheme 15). The mechanistic studies suggested that the base activates the complex Mn3. The active catalyst dehydrogenates methanol into formaldehyde and converts nitroarenes to anilines via transfer hydrogenation. The latter

Direct synthesis of acyl fluorides from carboxylic acids using benzothiazolium reagents

• Lilian M. Maas,
• Alex Haswell,
• Rory Hughes and
• Matthew N. Hopkinson

Beilstein J. Org. Chem. 2024, 20, 921–930, doi:10.3762/bjoc.20.82

• different amides, including dipeptides, under mild and operationally simple conditions in high yields. Mechanistic studies suggest that BT-SCF3 can generate acyl fluorides from carboxylic acids via two distinct pathways, which allows the deoxyfluorinating reagent to be employed in sub-stoichiometric amounts

• under mild and operationally simple conditions while peptide coupling between two amino acids could be efficiently conducted using the longer-chain perfluoroalkyl reagent BT-SC5F11. Mechanistic studies revealed that each equivalent of the benzothiazolium reagent can feasibly generate two equivalents of

Advancements in hydrochlorination of alkenes

• Daniel S. Müller

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

• radical D which is then trapped by TsCl to produce the corresponding alkyl chloride E. Detailed mechanistic studies on a related reaction were recently reported by Shenvi and co-workes [84]. These studies alternatively suggest that intermediate C could also be the result not of a non-simultaneous addition

Palladium-catalyzed three-component radical-polar crossover carboamination of 1,3-dienes or allenes with diazo esters and amines

• Geng-Xin Liu,
• Xiao-Ting Jie,
• Ge-Jun Niu,
• Li-Sheng Yang,
• Xing-Lin Li,
• Jian Luo and
• Wen-Hao Hu

Beilstein J. Org. Chem. 2024, 20, 661–671, doi:10.3762/bjoc.20.59

• amine and the traces amount of water in this reaction system may serve as proton sources for the formation of hybrid α-ester alkylpalladium radical. On the basis of above mechanistic studies and previous reports [47][48][49][50][52][58], the following plausible mechanisms are proposed for the palladium

Green and sustainable approaches for the Friedel–Crafts reaction between aldehydes and indoles

• Periklis X. Kolagkis,
• Eirini M. Galathri and
• Christoforos G. Kokotos

Beilstein J. Org. Chem. 2024, 20, 379–426, doi:10.3762/bjoc.20.36

Photochromic derivatives of indigo: historical overview of development, challenges and applications

• Gökhan Kaplan,
• Zeynel Seferoğlu and
• Daria V. Berdnikova

Beilstein J. Org. Chem. 2024, 20, 228–242, doi:10.3762/bjoc.20.23

• and unsymmetrical N,N'-substituted alkyl- and arylindigos with tunable thermal half-lives (follow-up mechanistic studies in 2022) 2018: first report on photochromic monoarylated indigos Synthesis of indigo derivatives Indigo (Ind) is one of the oldest organic molecules, which has been used as a dye

Recent advancements in iodide/phosphine-mediated photoredox radical reactions

• Tinglan Liu,
• Yu Zhou,
• Junhong Tang and
• Chengming Wang

Beilstein J. Org. Chem. 2023, 19, 1785–1803, doi:10.3762/bjoc.19.131

• photoredox radical reactions are relatively scarce [52], representing an unexplored area that requires further investigation. Developing asymmetric methodologies in this domain holds great promise for future exploration. Last but not the least, conducting detailed mechanistic studies on iodide/phosphine