Visible-light-driven NHC and organophotoredox dual catalysis for the synthesis of carbonyl compounds

• Vasudevan Dhayalan

Beilstein J. Org. Chem. 2025, 21, 2584–2603, doi:10.3762/bjoc.21.200

• 1,4-dicarbonyl compounds 23, valuable boron intermediates, from readily available starting materials and catalysts. The dual catalysis, merging NHC and photocatalysts, involves an radical species B and boryl radicals D, which undergo rapid radical–radical cross-coupling to yield the borylated 1,4

Transformation of the cyclohexane ring to the cyclopentane fragment of biologically active compounds

• Natalya Akhmetdinova,
• Ilgiz Biktagirov and
• Liliya Kh. Faizullina

Beilstein J. Org. Chem. 2025, 21, 2416–2446, doi:10.3762/bjoc.21.185

• rearrangement to lupane derivatives containing the betulin framework. This reaction was induced by a number of catalysts, including hydrogen chloride, montmorillonite K10, and boron trifluoride etherate. As a result, promising derivatives for the synthesis of ceanothic acid analogues were obtained [106][107

Pathway economy in cyclization of 1,n-enynes

• Hezhen Han,
• Wenjie Mao,
• Bin Lin,
• Maosheng Cheng,
• Lu Yang and
• Yongxiang Liu

Beilstein J. Org. Chem. 2025, 21, 2260–2282, doi:10.3762/bjoc.21.173

• -ynes were employed by the García group to construct borylated polycyclic products via a temperature-controlled boracyclization reaction mediated by BCl3 (Scheme 34) [47]. At 0 °C, BCl3-mediated activation of the alkyne triggered an intramolecular [2 + 2] cycloaddition, generating a boron-chlorine

Approaches to stereoselective 1,1'-glycosylation

• Daniele Zucchetta and
• Alla Zamyatina

Beilstein J. Org. Chem. 2025, 21, 1700–1718, doi:10.3762/bjoc.21.133

• presence of boron trifluoride etherate as promoter to afford the β,α-1,1'-linked disaccharide 12 in 52% yield (Scheme 2). The electron-withdrawing effect of the 2-azido group in the structurally similar donor 13 led to a significant drop in efficiency and the formation of the desired disaccharide 14 along

• coordination of the boron center with the remaining C2-OH group increases its acidity, thereby generating in situ an acidic catalyst for the activation of the glycosyl donor [62][63]. In this approach, the use of glycosyl phosphites of gluco- (35) and galacto- (38) configuration as donors, in combination with

Copper catalysis: a constantly evolving field

• Elena Fernández and
• Jaesook Yun

Beilstein J. Org. Chem. 2025, 21, 1477–1479, doi:10.3762/bjoc.21.109

• community in that it elegantly reviews recent advances in allylation reactions of copper-catalyzed asymmetric allylic substitution reactions of chiral secondary alkylcopper species [5]. In summary, the contribution includes stereospecific transmetalations of organolithium and -boron compounds, copper

Advances in nitrogen-containing helicenes: synthesis, chiroptical properties, and optoelectronic applications

• Meng Qiu,
• Jing Du,
• Nai-Te Yao,
• Xin-Yue Wang and
• Han-Yuan Gong

Beilstein J. Org. Chem. 2025, 21, 1422–1453, doi:10.3762/bjoc.21.106

• emitters. Boron–nitrogen co-doping strategies, in particular, have facilitated the development of materials with ultra-narrowband emissions, near-unity photoluminescence quantum yields, and electroluminescence dissymmetry factors (|gEL|) exceeding 10−3. Likewise, heteroatom co-doping with oxygen, sulfur

• reviewed boron-doped helicenes, emphasizing their roles in chiral materials design [12], while Maeda and Ema explored the circularly polarized luminescence (CPL) properties of azahelicenes [13]. However, despite these valuable contributions, a dedicated and up-to-date overview of nitrogen-doped helicenes

• helicenes. Particular attention is given to multi-heteroatom systems co-doped with elements such as boron, oxygen, sulfur, and selenium, highlighting their influence on CPL performance and structure–property relationships. We classify the nitrogen-doped helicenes into only N-containing helicenes, B,N

Recent advances in synthetic approaches for bioactive cinnamic acid derivatives

• Betty A. Kustiana,
• Galuh Widiyarti and
• Teni Ernawati

Beilstein J. Org. Chem. 2025, 21, 1031–1086, doi:10.3762/bjoc.21.85

• the catalyst surface 159 using air as O2 source (Scheme 49A) [24]. On the other hand, Wang and co-workers (2019) employed a porous boron nitride (pBN)-supported Au catalyst (Au/pBN) to prepare the ester 44, also via the formation of hemiacetal under O2 atmosphere (Scheme 49B) [25]. Wei and co-workers

Recent advances in controllable/divergent synthesis

• Jilei Cao,
• Leiyang Bai and
• Xuefeng Jiang

Beilstein J. Org. Chem. 2025, 21, 890–914, doi:10.3762/bjoc.21.73

• cleave the S(VI)–F bond and activate the Si–C bond. DFT calculations indicate that the reaction proceeds via the formation of a difluoroborate phenylacetylene intermediate 94’’ by in situ generation from boron trifluoride etherate and silicon-protected phenylacetylene 94, which activates the S–F bond of

• double methylene insertions into nitrogen–boron bonds [53]. Copper-catalyzed substrate-controlled carbonylative synthesis of α-keto amides and amides [54]. Divergent sulfur(VI) fluoride exchange linkage of sulfonimidoyl fluorides and alkynes [55]. Modular and divergent syntheses of protoberberine and

Cu–Bpin-mediated dimerization of 4,4-dichloro-2-butenoic acid derivatives enables the synthesis of densely functionalized cyclopropanes

• Patricia Gómez-Roibás,
• Andrea Chaves-Pouso and
• Martín Fañanás-Mastral

Beilstein J. Org. Chem. 2025, 21, 877–883, doi:10.3762/bjoc.21.71

• the copper–boron bond into 1. The dual functionality of this substrate imposed a question related to the regioselectivity of the Cu–Bpin insertion since it can potentially behave as an α,β-unsaturated ester or an allylic substrate [16][17][18][19]. To shed some light into this issue, we ran the

Light-enabled intramolecular [2 + 2] cycloaddition via photoactivation of simple alkenylboronic esters

• Lewis McGhie,
• Hannah M. Kortman,
• Jenna Rumpf,
• Peter H. Seeberger and
• John J. Molloy

Beilstein J. Org. Chem. 2025, 21, 854–863, doi:10.3762/bjoc.21.69

• energy sensitizers, would represent an attractive platform for future reaction design. Here, we disclose the photoactivation of simple alkenylboronic esters established using alkene scrambling as a rapid reaction probe to identify a suitable catalyst and boron motif. Cyclic voltammetry, UV–vis analysis

• , and control reactions support sensitization, enabling an intramolecular [2 + 2] cycloaddition to be realized accessing 3D bicyclic fragments containing a boron handle. Keywords: boron; catalysis; [2 + 2] cycloaddition; energy transfer; photochemistry; Introduction The strategic use of a photon to

• reactivity in EnT catalysis has also been intensively pursued (Figure 1B). The controlled geometric isomerization of boron-containing conjugated dienes [42], styrenes [43][44][45] and β-boryl acrylates [46][47] has been established with great effect, while elegant [2 + 2] cycloaddition strategies to readily

Development and mechanistic studies of calcium–BINOL phosphate-catalyzed hydrocyanation of hydrazones

• Carola Tortora,
• Christian A. Fischer,
• Sascha Kohlbauer,
• Alexandru Zamfir,
• Gerd M. Ballmann,
• Jürgen Pahl,
• Sjoerd Harder and
• Svetlana B. Tsogoeva

Beilstein J. Org. Chem. 2025, 21, 755–765, doi:10.3762/bjoc.21.59

• bioactive α-hydrazino acids [46][47][48]. This reaction has also been achieved by a lanthanide–PYBOX complex [49] and through asymmetric transfer hydrocyanation of aldimines with a boron compound [50]. Hence, we reasoned that the enantioselective hydrocyanation of hydrazones might be possible with a calcium

• of 9 (with a collinear arrangement of Ca–C–N) was found to be a sizable 3.3 kcal·mol−1 higher in energy than the preferred isonitrile, conforming to earlier anticipations based on computations of alkaline earth metal dicyanides [54]. Similarly, it also has been recently observed that boron-catalyzed

• transfer hydrocyanation of alkenes proceeds via (boron) isocyanides [50]. If calcium cyanide would be preferred over isocyanide, hydrocyanation would hardly be possible. A principally conceivable "hydroisocyanation" of hydrazone is therefore precluded. The relative stability of alkaline earth metal

Recent advances in allylation of chiral secondary alkylcopper species

• Minjae Kim,
• Gwanggyun Kim,
• Doyoon Kim,
• Jun Hee Lee and
• Seung Hwan Cho

Beilstein J. Org. Chem. 2025, 21, 639–658, doi:10.3762/bjoc.21.51

• transmetalation sequence (Scheme 6). For secondary boronic esters, Morken and co-workers conducted a systematic investigation to develop an efficient activation strategy [47]. Computational studies using DFT revealed an important relationship between the length of the boron–carbon bonds and the corresponding

• complex's chemical behavior (Scheme 6). Among the analyzed four-coordinate boron species, the unreactive trialkoxyborate complex A exhibited the most compact B–C bond at 1.621 Å. Following a clear trend, the B–C bond distance progressively lengthened as oxygen atoms were substituted with elements of lower

• bearing quaternary stereogenic centers with high stereospecificity. This methodology represents a significant advancement in the construction of challenging all-carbon quaternary stereogenic centers through stereospecific allylic substitution reactions. To elucidate the origin of the selective boron group

Entry to 2-aminoprolines via electrochemical decarboxylative amidation of N‑acetylamino malonic acid monoesters

• Olesja Koleda,
• Janis Sadauskis,
• Darja Antonenko,
• Edvards Janis Treijs,
• Raivis Davis Steberis and
• Edgars Suna

Beilstein J. Org. Chem. 2025, 21, 630–638, doi:10.3762/bjoc.21.50

• BDD (boron-doped diamond) delivered 6a in reduced yields (Table 1, entries 11 and 12). Finally, brief examination of passed charge returned 2.0 F as the optimal amount. The amount of charge could be increased to 2.5 F in case of incomplete conversion of the starting 6a, however, further rise above 2.5

Unraveling aromaticity: the dual worlds of pyrazole, pyrazoline, and 3D carborane

• Zahra Noori,
• Miquel Solà,
• Clara Viñas,
• Francesc Teixidor and
• Jordi Poater

Beilstein J. Org. Chem. 2025, 21, 412–420, doi:10.3762/bjoc.21.29

• Barcelona, Spain 10.3762/bjoc.21.29 Abstract A new series of o-carborane-fused pyrazoles has been recently successfully synthesized. This fusion was expected to create a hybrid 3D/2D aromatic system, combining the 3D aromaticity of o-carborane with the 2D aromaticity of pyrazole. However, while the boron

• therefore non-aromatic. Even when fused with benzene via a C–C bond, pyrazoline remains non-aromatic, which is the case of indazoline. Icosahedral carboranes are globular molecular clusters made of carbon and boron, displaying 3D aromaticity [12][13][14][15]. Their unique properties – such as aromaticity

• , exceptional thermal and chemical stability, and robust synthetic versatility [16][17] – make carborane derivatives essential components in various fields. These include pharmaceuticals [18][19][20][21][22], boron neutron capture therapy (BNCT) [23][24][25][26], organometallic ligands [27], and functional

Red light excitation: illuminating photocatalysis in a new spectrum

• Lucas Fortier,
• Corentin Lefebvre and
• Norbert Hoffmann

Beilstein J. Org. Chem. 2025, 21, 296–326, doi:10.3762/bjoc.21.22

Nickel-catalyzed cross-coupling of 2-fluorobenzofurans with arylboronic acids via aromatic C–F bond activation

• Takeshi Fujita,
• Haruna Yabuki,
• Ryutaro Morioka,
• Kohei Fuchibe and
• Junji Ichikawa

Beilstein J. Org. Chem. 2025, 21, 146–154, doi:10.3762/bjoc.21.8

• -arylbenzofuran 3ab (Table 2, entry 4) compared to that of 1a (X = F, quant.). The strong interaction between fluorine and boron in H likely facilitates β-fluorine elimination and transmetallation. Thus, the considerably different result observed with 1a is attributed to the distinct mechanistic aspects of the

Germanyl triazoles as a platform for CuAAC diversification and chemoselective orthogonal cross-coupling

• John M. Halford-McGuff,
• Thomas M. Richardson,
• Aidan P. McKay,
• Frederik Peschke,
• Glenn A. Burley and
• Allan J. B. Watson

Beilstein J. Org. Chem. 2024, 20, 3198–3204, doi:10.3762/bjoc.20.265

• of borylated functional groups, allowing orthogonal cross-coupling, whilst also offering excellent stability compared to boron-based reagents [57][58][59][60][61][62][63][64][65][66][67]. Based on their utility and stability, germanium units could therefore be useful within CuAAC reactions and offer

• . studentship. G.A.B., F.P., and A.J.B.W. thank the Leverhulme Trust (RPG-2020-380). A.J.B.W. thanks the Leverhulme Trust for a Research Fellowship (RF-2022-014) and the EPSRC Programme Grant ‘‘Boron: Beyond the Reagent’’ (EP/W007517/1) for support.

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

• synthesis of various halogenated 1,3-oxazine 50 and 2-oxazoline derivatives 51 using boron trihalides as the halogen source [6][49]. They found that the choice of halogen source influences the reaction outcomes. With the use of BCl3 (Scheme 28), N-cinnamylbenzamides 52 were transformed to give the

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

• , albeit, in low yield (Scheme 19) [25]. Cleavage of the benzyl groups using boron tribromide afforded β-31a. In contrast to indirubin-N-rhamnoside 17a, its isomer β-31a proved to be rather unstable. This fact was already earlier observed for indigo-N-rhamnoside 5d and again suggests that compounds

C–C Coupling in sterically demanding porphyrin environments

• Liam Cribbin,
• Brendan Twamley,
• Nicolae Buga,
• John E. O’ Brien,
• Raphael Bühler,
• Roland A. Fischer and
• Mathias O. Senge

Beilstein J. Org. Chem. 2024, 20, 2784–2798, doi:10.3762/bjoc.20.234

• stability than boronic acids and other employed esters as the four methyl groups protect the boron center from attack of water [44][45], preventing protodeboronation from the hydrolysis route. However, protodeboronation can be complex when it comes to pKa considerations, for example, 3,5

Computational design for enantioselective CO₂ capture: asymmetric frustrated Lewis pairs in epoxide transformations

• Maxime Ferrer,
• Iñigo Iribarren,
• Tim Renningholtz,
• Ibon Alkorta and
• Cristina Trujillo

Beilstein J. Org. Chem. 2024, 20, 2668–2681, doi:10.3762/bjoc.20.224

• boron bears CF3 substituents. Thus, an acidic boron atom seems to increase the reactivity of the considered system. Concerning the LB, it appears that, as opposed to the first group of compounds, a phosphorus atom is more active than a nitrogen atom. Asymmetric catalysis After examining the volcano

• excess. Following the volcano plot analysis presented in the previous section, F3_NB_C5_CF3 emerged as one of the top FLP catalysts under study. This catalyst, adhering to mechanism 1, incorporates a CF3 group on the boron atom, serving as a simplified version of the B(p-HC6F4)3. Notably, the nitrogen in

• plot analysis reveals that the best candidate is F3_NB_C5_CF3, which is the catalyst based on the 2-borylbenzenamine scaffold, with a pyrrolidine substituent on the nitrogen atom and CF3 substituents on the boron. Through strategic modification of the Lewis base substituents, a stereoselective catalyst

Transition-metal-free synthesis of arylboronates via thermal generation of aryl radicals from triarylbismuthines in air

• Yuki Yamamoto,
• Yuki Konakazawa,
• Kohsuke Fujiwara and
• Akiya Ogawa

Beilstein J. Org. Chem. 2024, 20, 2577–2584, doi:10.3762/bjoc.20.216

• generating a boron radical (pinB•) by photoirradiation of (Bpin)2 and found that the addition of (PhS)2 was effective in generating the boron radical [30]. We therefore investigated this reaction by adding (PhS)2 as a Lewis base, but the yield of 3a was not improved and (PhS)2 was recovered almost

• control experiments and our previous studies, a proposed reaction pathway is shown in Scheme 5. First, thermal activation of triarylbismuthines in air forms aryl radicals together with the bismuth residues (i.e., metal bismuth and bismuth oxide). Alternatively, oxygen in air and/or boron-centered radicals

• File 138: Investigation of the boron residue in the crude mixture by 11B NMR measurement, characterization data of the compounds, and copies of 1H NMR and 13C{1H} NMR spectra. Acknowledgements We acknowledged Dr. Tran Dat Phuc and Mr. Soichiro Mita (Osaka Prefecture University) for their initial

Anion-dependent ion-pairing assemblies of triazatriangulenium cation that interferes with stacking structures

• Yohei Haketa,
• Takuma Matsuda and
• Hiromitsu Maeda

Beilstein J. Org. Chem. 2024, 20, 2567–2576, doi:10.3762/bjoc.20.215

• 2+-B(C6F5)4−, the distance between the boron of B(C6F5)4− and the central carbon of TATA+ was 7.32 Å, with an offset angle of 47.1° (Figure 3d, Figure 7a, and Figures S14 and S20 in Supporting Information File 1). On the other hand, in 2+-PCCp−, the PCCp− unit (centroid of the five-membered ring

• ) packing structures and (ii) enlarged views for the columnar structures. In (i), cation and anion are represented in cyan and magenta colors, respectively. In (ii), brown, pink, yellow, blue, yellow green, orange, and green (spherical) refer to carbon, hydrogen, boron, nitrogen, fluorine, phosphorus, and

• +-Cl−, (b) 2+-BF4−, and (c) 2+-PF6−. Atom color code: yellow, green, orange, and green (spherical) refer to boron, fluorine, phosphorus, and chlorine, respectively. (i) Single-crystal X-ray structures and (ii) interaction energies for the pairs (a) 2+-Cl−, (b) 2+-BF4−, and (c) 2+-PF6−. In (i), 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

• undivided cell using a boron-doped diamond (BDD) anode and a platinum cathode at constant current, resulting in 1,4-dicarbonyls with yields up to 91% and enantiomeric excesses (ee) greater than 99%. This methodology was demonstrated in the LSF of two complex natural product derivatives: a β-ionone

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

• essential to provide a comprehensive overview of this significant topic. Review Asymmetric allylation with boron-based reagents The research on the metal-free, asymmetric organocatalytic allylation of acylimines was pioneered in 2007 by Schaus and co-workers [24]. In their elegant approach, high

• excellent enantioselectivities (89–98% ee) and low to moderate yields (48–72%). The homologation step proceeds via the stereoretentive 1,2-migration of the vinyl group from the tetracoordinated boron to the highly electrophilic carbon of the diazomethane, concerted with the elimination of the nitrogen

• by a nucleophile, is energetically favoured over pathway via 77, in which the imine is activated directly by coordination to the Lewis acidic boron atom of the free imine complex. This supports the mechanism proposed in the original study based on the NMR experiments. In 2021, Jacobsen and co-workers