Unprecedented visible light-initiated topochemical [2 + 2] cycloaddition in a functionalized bimane dye

• Metodej Dvoracek,
• Brendan Twamley,
• Mathias O. Senge and
• Mikhail A. Filatov

Beilstein J. Org. Chem. 2025, 21, 500–509, doi:10.3762/bjoc.21.37

• light irradiation, undergoing rearrangement and photodegradation, so there may be a risk of degradation if irradiation using UV light is tried. Alternatively, the lack of a [2 + 2] cycloaddition of Me2B, may be due to its photophysical properties not allowing for a reaction to occur, rather than the

Molecular diversity of the reactions of MBH carbonates of isatins and various nucleophiles

• Zi-Ying Xiao,
• Jing Sun and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2025, 21, 286–295, doi:10.3762/bjoc.21.21

• Figure 1 and Figure 2, it can be found that the C=C bond is located in the unit of the pyrrolidine-2,5-dione, while the scaffold of indolin-2-one is connected via a C–C single bond with the unit of the pyrrolidine-2,5-dione. Therefore, an allyl rearrangement must proceed in the reaction process, which is

• used in the reaction, a direct Michael addition of the arylamine to the C=C bond of the maleimide unit and sequential elimination of carbon dioxide and tert-butoxide ion gives the intermediate B, which in turn undergoes an allylic rearrangement to afford the product 5. In this process, no extra

Emerging trends in the optimization of organic synthesis through high-throughput tools and machine learning

• Pablo Quijano Velasco,
• Kedar Hippalgaonkar and
• Balamurugan Ramalingam

Beilstein J. Org. Chem. 2025, 21, 10–38, doi:10.3762/bjoc.21.3

• four-step process involves allylation, Claisen rearrangement, isomerization, and oxidative dimerization. Each reaction step was optimized independently by using either online HPLC or in-line benchtop NMR spectroscopy to afford an overall yield of 67% in 66 iterative experiments over four linear

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

• contrast to P212121 in the low temperature phase (LTP). Note that the b-axis is roughly 1/5 of the c-axis observed at 90 K (the axial rearrangement is due to the change in space group). To discern the approximate temperature of the phase transition, the unit cell was measured in 20 K increments upon

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

• ][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

• pure propargyltrichlorosilane, it clearly demonstrated that this class of chiral Lewis bases regiospecifically catalyzed the addition of propargyltrichlorosilane to aldehydes, and that these catalysts did not induce the propargyl–allenyl metallotropic rearrangement albeit activating the C–Si bond. Thus

• propargyltrichlorosilane without N,N-diisopropylethylamine and (b) with N,N-diisopropylethylamine. It includes Gibbs free energies (kcal/mol) and Mulliken charges (in parentheses). Metallotropic rearrangement and regioselectivity issues. Asymmetric catalytic allenylation of aldehydes. Selective preparation of

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

• carried out without solvent and at room temperature, using copper(II) acetate as the catalyst. The reaction pathway of tert-butyl perbenzoate synthesis from benzyl nitriles 60 involves the formation of intermediate D. The Kornblum–DeLaMare rearrangement of peroxide D gives benzoyl cyanide E, which is

Structure and thermal stability of phosphorus-iodonium ylids

• Andrew Greener,
• Stephen P. Argent,
• Coby J. Clarke and
• Miriam L. O’Duill

Beilstein J. Org. Chem. 2024, 20, 2931–2939, doi:10.3762/bjoc.20.245

• correspond to a geometric rearrangement, e.g., Berry pseudorotation, which occurs prior to decomposition [31]. A large dihedral angle φ is thought to facilitate this rearrangement, thus accelerating decomposition [38][39]. Decomposition mechanism Further analysis was carried out to gain a better

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

• concentrate on various arylation reactions involving carbon and other heteroatoms, encompassing rearrangement reactions in the absence of any metal catalyst, and summarize advancements made in the last five years. Keywords: arylation reaction; diaryliodonium salts; electrophilic arylation reagent; metal-free

• arylation; rearrangement reaction; Introduction The chemistry of hypervalent iodine compounds is well-established and they are prevalent as oxidants and electrophilic reagents in organic conversions [1][2][3]. They have gained significant attention due to their high reactivity and ability to carry out

• 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

N-Glycosides of indigo, indirubin, and isoindigo: blue, red, and yellow sugars and their cancerostatic activity

• Peter Langer

Beilstein J. Org. Chem. 2024, 20, 2840–2869, doi:10.3762/bjoc.20.240

• product can be explained by rearrangement of the rhamnosyl group from the oxygen to the nitrogen atom. Oxidative debenzylation of 5a afforded 5b in high yield. Unfortunately, all attempts to remove the pivaloyl protective groups failed. On the other hand, employment of tri-O-acetyl-α-ʟ-rhamnosyl

Access to optically active tetrafluoroethylenated amines based on [1,3]-proton shift reaction

• Yuta Kabumoto,
• Eiichiro Yoshimoto,
• Bing Xiaohuan,
• Masato Morita,
• Motohiro Yasui,
• Shigeyuki Yamada and
• Tsutomu Konno

Beilstein J. Org. Chem. 2024, 20, 2776–2783, doi:10.3762/bjoc.20.233

• and 94% ee for (S)-23g). Disappointingly, when R is an alkyl group, the desired rearrangement products were rarely obtained, resulting in unidentified products together with a large amount of starting material. This may be due to the following reasons. Namely, when the substituent R is an aryl group

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

• preparation of biologically active compounds [15]. The synthesis was achieved via a sulfonyl group rearrangement driven by the azide–tetrazole equilibrium in quinazolines. The researchers utilized two synthetic pathways to prepare the target compounds. The first pathway involved a nucleophilic aromatic

Transition-metal-free decarbonylation–oxidation of 3-arylbenzofuran-2(3H)-ones: access to 2-hydroxybenzophenones

• Bhaskar B. Dhotare,
• Seema V. Kanojia,
• Chahna K. Sakhiya,
• Amey Wadawale and
• Dibakar Goswami

Beilstein J. Org. Chem. 2024, 20, 2655–2667, doi:10.3762/bjoc.20.223

• -hydroxybenzophenones are conventionally prepared via Fries rearrangement of a phenyl ester [10]. Organocatalytic methods have also been reported for the synthesis of 2-hydroxybenzophenones [11]. In addition, several metal-mediated methods for their synthesis have been reported. For example, the Rh-catalyzed

• rearrangement of 2-aryloxybenzaldehydes yielded 2-hydroxybenzophenone [12]. Pd-catalyzed o-hydroxylation of benzophenones gave moderate yield of the title compound, and Br-substituted substrates were found to be not compatible with this method [13]. Various metals (Rh, Cu, Ir etc.) were applied to catalyze 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

• alternative to the harsh Pummerer rearrangement. Methanol played a crucial role in achieving the desired transformation and it was suggested to promote the self-assembly of reagents 24 and 25 for the formation of 27, which allows the selective abstraction of H+ from the less sterically hindered side

Visible-light-mediated flow protocol for Achmatowicz rearrangement

• Joachyutharayalu Oja,
• Sanjeev Kumar and
• Srihari Pabbaraja

Beilstein J. Org. Chem. 2024, 20, 2493–2499, doi:10.3762/bjoc.20.213

• platform developed with an integrated system enabling a downstream process in a time and labor-efficient manner which facilitates the Achmatowicz rearrangement, resulting in a fast (10 min) formation of the dihydropyranone products. Keywords: Achmatowicz reaction; flow chemistry; furfuryl alcohols

• Achmatowicz rearrangement substrates for accessing highly decorated dihydropyranones [5]. In recent years, several groundbreaking approaches for the synthesis of dihydropyranones have been described by diverse groups of researchers [6]. These techniques do not require any pre-functionalization of non

• -prefunctionalized materials in order to proceed with the rearrangement. However, the Achmatowicz reaction or similar methodologies involve a catalytic to stoichiometric amount of oxidants such as m-CPBA [7], PCC [8], Br2 [9], NBS [10], DMDO [11], KBr/Oxone [12], Na2S2O8 [13], photosensitizers/O21 [14], or Me2S [15

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

• ; rearrangement; Introduction Nitrogen-containing organic compounds (sometimes referred to as alkaloids due to their basic properties) are of critical importance in medicinal chemistry because of their unique binding properties to biomolecules [1]. Out of 55 drug candidates, approved by the FDA in 2023, 28 (51

• diaziridine 110 with 88% ee albeit with a modest 42% yield. Overall, this is an interesting example of dearomative allylation of Ν-acylquinolinium salts, though enantioselectivity currently is too low to ensure wider practical application of the method. Enantioselective 2-aza-Cope rearrangement In 2008, a

• conceptually different methodology was reported by Rueping and co-workers [41] that was based on the aza-Cope rearrangement of in situ-formed N-α,α’-diphenyl-(α’’-allyl)methyliminium cations catalysed by the BINOL-derived chiral phosphoric acid 112 (Scheme 23). The amine 113 acting as the allyl donor source

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

• enantioselectivities of a kinetic resolution of benzyl alcohols and an enantiodivergent fluorination of allylic alcohols, observing good correlations for both reactions. Since then, the proposed NCI descriptors have been successfully applied to multiple different reactions, such as an allenoate Claisen rearrangement

Natural resorcylic lactones derived from alternariol

• Joachim Podlech

Beilstein J. Org. Chem. 2024, 20, 2171–2207, doi:10.3762/bjoc.20.187

From perfluoroalkyl aryl sulfoxides to ortho thioethers

• Yang Li,
• Guillaume Dagousset,
• Emmanuel Magnier and
• Bruce Pégot

Beilstein J. Org. Chem. 2024, 20, 2108–2113, doi:10.3762/bjoc.20.181

• Yang Li Guillaume Dagousset Emmanuel Magnier Bruce Pegot Université Paris-Saclay, UVSQ, CNRS, UMR 8180, Institut Lavoisier de Versailles, 78035 Versailles Cedex, France 10.3762/bjoc.20.181 Abstract Access to original ortho thioether derivatives was achieved through a [3,3]-rearrangement in a one

• -pot two-step protocol. Several aryl-SCF3 compounds are reported by variation of the nitrile or of the trifluoroalkyl sulfoxide starting material. The variation of the perfluoroalkyl chain was also possible. Keywords: ortho functionalization; rearrangement; sulfoxide; Introduction Since decades

• their ability to be engaged in such a rearrangement [4][5]. Upon activation with trifluoromethanesulfonic anhydride and under heating, we showed their transformation to ortho thioethers with a fairly acceptable selectivity towards the pathway of sulfilimine synthesis (Scheme 1b). Following our seminal

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

• iodoalkanes 89. Subsequent reaction with acylsilanes 90 leads to alcohols, which react by Brook rearrangement to enoxysilanes and form the intermediate 92. Following a Michael addition/cyclocondensation with methylhydrazine, 4-fluoropyrazoles 91 are regioselectively formed (Scheme 32) [115]. Bouillon

• . An advantage of this method for preparing 1,3,5-substituted pyrazoles is its tolerance towards a wide range of substituents. Trimethyl phosphite can be added to acetylene dicarboxylates 95 to generate a zwitterion that readily reacts with electrophiles. This zwitterion undergoes a rearrangement

• preparation of these pyrazoles involves the cycloaddition of diazo compounds generated in situ with (Z)-2-arylidene-2H-benzofuran-3-ones. This reaction yields intermediate spiropyrazolines, which react undergo 1,3-prototropic rearrangement to form the corresponding pyrazoles [175]. Aggarwal's method was also

Understanding X-ray-induced isomerisation in photoswitchable surfactant assemblies

• Beatrice E. Jones,
• Camille Blayo,
• Jake L. Greenfield,
• Matthew J. Fuchter,
• Nathan Cowieson and
• Rachel C. Evans

Beilstein J. Org. Chem. 2024, 20, 2005–2015, doi:10.3762/bjoc.20.176

• decreased rate of diffusion in the more viscous D2O could lead to slower rearrangement after reverse isomerisation into the E isomer morphology. This demonstrates that the solvent plays a crucial role in X-ray-induced reverse isomerisation in these systems, not only due to catalysis from the radiolysis

Harnessing the versatility of hydrazones through electrosynthetic oxidative transformations

• Aurélie Claraz

Beilstein J. Org. Chem. 2024, 20, 1988–2004, doi:10.3762/bjoc.20.175

• ’-dimethoxybenzilhydrazone (X = H, Cl). In these cases, the diazo compounds directly underwent both Wolff rearrangement and overoxidations to yield a mixture of the corresponding diphenyl acetal and benzil dimethyl acetal (akin to the conversion of 132 into 133 in Scheme 27), respectively (Scheme 29) [78]. Using a similar

Access to 2-oxoazetidine-3-carboxylic acid derivatives via thermal microwave-assisted Wolff rearrangement of 3-diazotetramic acids in the presence of nucleophiles

• Ivan Lyutin,
• Vasilisa Krivovicheva,
• Grigory Kantin and
• Dmitry Dar’in

Beilstein J. Org. Chem. 2024, 20, 1894–1899, doi:10.3762/bjoc.20.164

• 191036, Russian Federation 10.3762/bjoc.20.164 Abstract In this work, we report an efficient approach to 2-oxoazetidine-3-carboxylic acid derivatives based on a thermally promoted Wolff rearrangement of diazotetramic acids in the presence of nucleophiles. The method allows easy variation of the

• well as a wide range of nucleophiles provides access to a structural diversity of medically relevant 2-oxoazetidine-3-carboxylic acid amides and esters. Keywords: β-lactams; diazotetramic acids; nucleophiles; spirocycles; thermolysis; Wolff rearrangement; Introduction The importance of the β-lactam

• ketenes 2 generated by a thermally promoted Wolff rearrangement [3]. The interaction of such ketenes with nucleophiles of different nature could serve as a source of libraries of structurally diverse 2-oxoazetidine-3-carboxylic acid derivatives 3 (Scheme 1). The 2-oxoazetidine-3-carboxylic acid

The Groebke–Blackburn–Bienaymé reaction in its maturity: innovation and improvements since its 21st birthday (2019–2023)

• Cristina Martini,
• Muhammad Idham Darussalam Mardjan and
• Andrea Basso

Beilstein J. Org. Chem. 2024, 20, 1839–1879, doi:10.3762/bjoc.20.162

• reaction can be considered the third in importance after Ugi [3] and Passerini [4] ones, and, as the two venerable reactions, is an α-addition of an electrophile and a nucleophile to an isocyanide, followed by a suitable rearrangement, as depicted in Scheme 1. Compared with the Passerini and Ugi reactions

• provide the ammonium 77. The intermediate 77 underwent Steven rearrangement to give a bridged polyheterocycle 78 in 28% yield. Unlike the previous examples, Jeong et al. [60] developed a cascade reaction by installing the additional ring prior to the GBB reaction (Scheme 26). The bifunctional 2-(2

Harnessing unprotected deactivated amines and arylglyoxals in the Ugi reaction for the synthesis of fused complex nitrogen heterocycles

• Javier Gómez-Ayuso,
• Pablo Pertejo,
• Tomás Hermosilla,
• Israel Carreira-Barral,
• Roberto Quesada and
• María García-Valverde

Beilstein J. Org. Chem. 2024, 20, 1758–1766, doi:10.3762/bjoc.20.154

• different competitive reactions triggered by it, such as the interrupted Ugi reaction resulting from the competitive addition over the nitrilium intermediate [9][10] or the split-Ugi reaction arising from a competitive O,N-acyl transference on the imidate intermediate, through a remote Mumm rearrangement

Chemo-enzymatic total synthesis: current approaches toward the integration of chemical and enzymatic transformations

• Ryo Tanifuji and
• Hiroki Oguri

Beilstein J. Org. Chem. 2024, 20, 1693–1712, doi:10.3762/bjoc.20.151

• hybrid syntheses of cotylenol (1) and brassicicenes [19]. The key oxidative allylic rearrangement was conducted enzymatically, while the skeletal rearrangement originally mediated by P450 enzymes in the biosynthetic pathway was achieved through chemical transformation. Hence, this strategy can be

• of scaffold 6 yield a series of intermediates and natural products, including cotylenol (1) and brassicicenes I and B (9 and 10), as well as brassicicene O (12), which possesses a distinct scaffold resulting from a skeletal rearrangement. To the core scaffold 6, the P450 enzymes, BscB and BscC

• , introduce hydroxy groups at C8 and C16 to produce FD-8β,16-diol (7), and BscE-catalyzed O-methylation generates the putative intermediate 8. The subsequent oxidative allylic rearrangement (8→9), catalyzed by the nonheme iron(II) and 2-oxoglutarate (Fe(II)/2OG)-dependent dioxygenase BscD, was a key step