Synthesis of electrophile-tethered preQ₁ analogs for covalent attachment to preQ₁ RNA

• Laurin Flemmich and
• Ronald Micura

Beilstein J. Org. Chem. 2025, 21, 483–489, doi:10.3762/bjoc.21.35

• covalency. We believe that these exciting new research directions will be furthered by the efficient synthetic routes to covalent RNA binders presented here. Experimental General procedure for reductive aminations (compounds 3a, 4b–d, 11, and 12). Aldehyde 9 or 10 (50.0 mg, 282 µmol) was suspended in

Organocatalytic kinetic resolution of 1,5-dicarbonyl compounds through a retro-Michael reaction

• James Guevara-Pulido,
• Fernando González-Pérez,
• José M. Andrés and
• Rafael Pedrosa

Beilstein J. Org. Chem. 2025, 21, 473–482, doi:10.3762/bjoc.21.34

• , enantioselectivity increased until a specific time, and after that, the enantiomeric ratio decreased (compare entries 1–3 and 21–23 in Table 1). The interesting result is that the major enantiomer in the enantioenriched mixture is now the opposite of the one obtained when the ketone and the α,β-unsaturated aldehyde

New tandem Ugi/intramolecular Diels–Alder reaction based on vinylfuran and 1,3-butadienylfuran derivatives

• Yuriy I. Horak,
• Roman Z. Lytvyn,
• Andrii R. Vakhula,
• Yuriy V. Homza,
• Nazariy T. Pokhodylo and
• Mykola D. Obushak

Beilstein J. Org. Chem. 2025, 21, 444–450, doi:10.3762/bjoc.21.31

• the Ugi reaction with a maleic acid to form adducts containing both, diene and dienophilic fragments. It was found that aldehyde 1a reacted with amines 2, isonitriles 3, and maleic acid monoanilide (4a) to form an adduct that spontaneously underwent a [4 + 2] cycloaddition giving furoisoindoles 5a–h

Identification and removal of a cryptic impurity in pomalidomide-PEG based PROTAC

• Bingnan Wang,
• Yong Lu and
• Chuo Chen

Beilstein J. Org. Chem. 2025, 21, 407–411, doi:10.3762/bjoc.21.28

• synthesis of iVeliparib-AP6 [5] starts with a nucleophilic aromatic substitution (SNAr) reaction wherein 4-fluorothalidomide (1) reacts with amino-PEG7-OH 2 to give alcohol 3 (Scheme 1). Subsequent alcohol oxidation followed by reductive amination of the resulting aldehyde 4 with veliparib [6][7] provides

Streamlined modular synthesis of saframycin substructure via copper-catalyzed three-component assembly and gold-promoted 6-endo cyclization

• Asahi Kanno,
• Ryo Tanifuji,
• Satoshi Yoshida,
• Sota Sato,
• Saori Maki-Yonekura,
• Kiyofumi Takaba,
• Jungmin Kang,
• Kensuke Tono,
• Koji Yonekura and
• Hiroki Oguri

Beilstein J. Org. Chem. 2025, 21, 226–233, doi:10.3762/bjoc.21.14

• of saframycin A (1) is assembled from two molecules of ʟ-tyrosine derivative 5 and peptidyl aldehyde 6 by non-ribosomal peptide synthetases (NRPS, Scheme 1a) [15][16][17][18][19][20][21]. The pivotal NRPS module, SfmC, catalyzes iterative regio- and stereoselective Pictet–Spengler (PS)-type

• structure of 16 was confirmed by serial X-ray crystallography using an X-ray free-electron laser (XFEL) [deposition number CCDC 2352718) [54][55]. We then performed a Strecker-type reaction on the aldehyde 16 to construct an α-aminonitrile 17. To our delight, the key intermediate, 2,3-diaminobenzofuran 11

Cu(OTf)₂-catalyzed multicomponent reactions

• Sara Colombo,
• Camilla Loro,
• Egle M. Beccalli,
• Gianluigi Broggini and
• Marta Papis

Beilstein J. Org. Chem. 2025, 21, 122–145, doi:10.3762/bjoc.21.7

• Pd-catalyzed cross-coupling reactions, allowing the formation of C–C and C–N bonds in the o-position of the aryl chalcogen compounds. α-Aminophosphonates 14 were the result of a one-pot condensation of an aldehyde, a primary amine and phosphite P(OMe)3 with copper triflate acting as Lewis acid

• aldehyde, urea and a 1,3-dicarbonyl compound [26][27]. In these reactions, the use of catalytic Cu(OTf)2 proved to be an excellent triflate surrogate, also revealing a remarkable reuse activity. The first example of a Biginelli reaction carried out with Cu(OTf)2 catalysis was reported by Sudalai and co

• is plausible to assume as the key step for ring formation an aza-Diels–Alder reaction between the alkyne and the imine generated by dehydration between the aldehyde and aniline. The catalyst promotes the formation of the imine XI, while the high regioselectivity is ascribable to the favored

Recent advances in organocatalytic atroposelective reactions

• Henrich Szabados and
• Radovan Šebesta

Beilstein J. Org. Chem. 2025, 21, 55–121, doi:10.3762/bjoc.21.6

• axially chiral N-aryl succinimides 54. The tentative mechanism comprises the formation of the Breslow intermediate Int-31 from the catalyst carbene and aldehyde 52, which then adds to the electron-deficient double bond of maleimide giving rise to Int-32 (Scheme 17). Chi and co-workers developed an

Synthesis of 2H-azirine-2,2-dicarboxylic acids and their derivatives

• Anastasiya V. Agafonova,
• Mikhail S. Novikov and
• Alexander F. Khlebnikov

Beilstein J. Org. Chem. 2024, 20, 3191–3197, doi:10.3762/bjoc.20.264

• separate impurities. In these cases, as well as in reactions giving low aldehyde yields in the first step (4b,d), the second developed reaction sequence turned out to be more effective. In the second approach, the oxidation of aldehydes 4 with Oxone to acids 5 occurs with yields close to quantitative, and

Synthesis of extended fluorinated tripeptides based on the tetrahydropyridazine scaffold

• Thierry Milcent,
• Pascal Retailleau,
• Benoit Crousse and
• Sandrine Ongeri

Beilstein J. Org. Chem. 2024, 20, 3174–3181, doi:10.3762/bjoc.20.262

• order to lead to the expected fluorinated tetrahydropyridazines (Figure 4). Results and Discussion First, the difluoro- and trifluoromethylated hydrazones 3a–f were synthesized by condensing the corresponding hydrazide with the fluorinated aldehyde hemiacetal 2a or 2b (Scheme 2). Benzyl and tert-butyl

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

• other approaches such as visible light, microwaves, heterogeneous catalysis, and ultrasound [12][13][14][15]. Due to its versatility, one of the most prevalent of these MCRs is the Ugi reaction [16]. This reaction generally combines an isocyanide with an acid, an amine, and an aldehyde or ketone to

• development as a therapeutic agent for AD. Petasis reaction: Continuing in the context of the development of MTDLs, in 2023 Madhav et al. [40] reported the synthesis of pyrazine-based MTDLs using the Petasis reaction, which involves a secondary amine, a suitable aldehyde, and a substituted boronic acid in the

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

• orientation of p-nitrophenyl units, due to the shielding of the bound aldehyde substrate from the incoming diene. The catalytic inactivity of 5 demonstrated the requirement of macrocyclic character for the potential catalysts. Later in 2009, the same group reported an organocatalyzed diastereoselective aldol

• porphyrin catalyst, amine, aldehyde, EDA, or light source – completely halted the reaction, resulting in no product formation. The further study found that porphyrins with both electron-withdrawing and electron-donating substituents at the meso-positions were catalytically active. Additionally, among

• studies were focused on using these porphyrins as photooxidants in the red light-induced α-alkylation of aldehyde with ethyl diazoacetate. The reported reaction proceeds smoothly, giving 75% and 70% yields for macrocycles 18 and 78, respectively (Figure 17a). Irradiation of porphyrin photocatalysts by red

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

• toward electrophiles [14][15][16][17][18][19]. Consequently, all reported asymmetric catalytic aldehyde allenylation methods are currently limited to metal/metalloid reagents bearing R2 substituents [21][22][23][24][25][26][27][28][29][30][31][32][33][34], except for the methods with

• the allenylation reaction of benzaldehyde (1a) as model aldehyde with catalyst 3 (Scheme 4). Catalyst 3 was the only catalyst previously studied by Nakajima for propargyltrichlorosilane [36]. Ever since Nakajima reported the beneficial effect of N,N-diisopropylethylamine on the reaction rate of the

• aldehyde allylation reaction with allyltrichlorosilane [47], it has been routinely employed in analogous chlorosilane reactions [48][49][50][51][52][53][54][55]. However, a mechanistic basis of its role on the observed rate acceleration remains elusive while it certainly functions as a scavenger of HCl

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

• . The oxidation of benzyl alcohol 62 with TBHP results in aldehyde C, HAT from which by tert-butoxy radical A leads to the C-centered radical D. Subsequent recombination of radicals D and B provides the target product 63. An enantioselective peroxidation method of alkylaromatics with TBHP using chiral

• ]. The set of tert-butoxy A and tert-butylperoxy B radicals are formed from TBHP during the Cu(I)/Cu(II) redox cycle. The Cu(II)/TBHP system also provides oxidation of benzyl alcohol 80 to the corresponding aldehyde C. The reaction of isocyanate 81 with aldehyde C generates oxazoline D, HAT from D by the

• Fe-catalyzed decarbonylative alkylation–peroxidation of alkenes 130 with aliphatic aldehydes 131 and TBHP to provide chain elongated peroxides 132 was developed (Scheme 44a) [103]. Aliphatic aldehyde 131 were used as the sources of 1°, 2°, 3° alkyl moieties via decarbonylation strategy. The proposed

Synthesis of fluorinated acid-functionalized, electron-rich nickel porphyrins

• Mike Brockmann,
• Jonas Lobbel,
• Lara Unterriker and
• Rainer Herges

Beilstein J. Org. Chem. 2024, 20, 2954–2958, doi:10.3762/bjoc.20.248

• -synthetic modification of this porphyrin proved to be difficult. Therefore, we have integrated the acid group into the aldehyde component of the Rothemund reaction to prepare the target porphyrin. In initial tests, we have established that trifluoroacetic acid can be replaced by perfluorinated alkyl

• ) as the aldehyde component due to its commercial availability. A OH group was introduced to serve as the nucleophile in the Williamson ether synthesis with the triflates 16, 17, and 18 (Scheme 2). Towards this end, 3,4,5-trimethoxybenzaldehyde (19) was iodinated using N-iodosuccinimide (NIS) to give

• Williamson ether synthesis to yield 22 (78%), 23 (44%), and 24 (44%). Compounds 22, 23, and 24 were used as aldehyde components in the Rothemund-type synthesis of metal-free porphyrins 26 (9%), 27 (18%), and 28 (21%) (see Scheme 3). Metalation was achieved with nickel acetylacetonate to obtain the ester

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

• /Education Center for Excellence in Molecular Sciences Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China 10.3762/bjoc.20.242 Abstract The selective C–H trifluoromethylthiolation of aldehyde hydrazones afforded interesting fluorinated building blocks, which could be used as a

• trifluoromethylthiolated molecules, which could be used as synthetic handles for synthesizing more complex molecules, is still appealing. In this context, we turned our attention to the trifluoromethylthiolated hydrazones, an interesting building block. Indeed, aldehyde hydrazones have been well studied and used in

• various transformations [54][55][56][57][58][59][60][61][62][63][64]. In consequence, a large number of transition-metal-catalyzed or radical-mediated processes for C–H functionalization of aldehyde hydrazones has flourished over the years. An ideal scenario for a direct and sustainable synthetic route

Synthesis of pyrrole-fused dibenzoxazepine/dibenzothiazepine/triazolobenzodiazepine derivatives via isocyanide-based multicomponent reactions

• Marzieh Norouzi,
• Mohammad Taghi Nazeri,
• Ahmad Shaabani and
• Behrouz Notash

Beilstein J. Org. Chem. 2024, 20, 2870–2882, doi:10.3762/bjoc.20.241

• with 1,10-phenanthroline as cyclic imine under solvent-free conditions for the synthesis of pyrrole-fused phenanthroline. This reaction proceeds via in situ formation of zwitterion I through reaction of the aldehyde and malononitrile followed by 1,3-dipolar cycloaddition (Scheme 1a) [41]. Chen and co

Multicomponent synthesis of α-branched amines using organozinc reagents generated from alkyl bromides

• Baptiste Leroux,
• Alexis Beaufils,
• Federico Banchini,
• Olivier Jackowski,
• Alejandro Perez-Luna,
• Fabrice Chemla,
• Marc Presset and
• Erwan Le Gall

Beilstein J. Org. Chem. 2024, 20, 2834–2839, doi:10.3762/bjoc.20.239

• 16 h at 80 °C (Table 1, entry 2). However, its suitability in the multicomponent coupling with an amine and an aldehyde still had to be demonstrated as there was no precedent for such a Mannich multicomponent coupling involving nonstabilized organozinc halides using THF or 2-MeTHF as solvent. To our

• species 2 were collected using a syringe and allowed to react with an amine 3 and an aldehyde 4 under moderate heating (Scheme 2). The multicomponent couplings proceeded smoothly, with an acceptable yield of the α-branched amine being obtained after 3 h at 50 °C. A range of secondary amines as well as

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

• ]. As a diastereoselective synthesis, reductive coupling reactions of commercially available 4-bromo-3,3,4,4-tetrafluoro-1-butene and glyceraldehyde 10a, its imine derivative 11, or Garner's aldehyde 10b have been reported [23][24]. Although the diastereoselectivities were low in some cases, 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

• product 6 was not observed. Instead, among the several side-products formed, we were able to isolate α-aminoamidine 7, as the result of a 3C Ugi-type reaction between an aldehyde obtained from an oxidation–hydrolysis process of compound 5, tert-butyl isocyanide and 2 equivalents of aniline, and the

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

• a new family of isatin-based α-acetamide carboxamide oxindole hybrids using the versatile Ugi four-component reaction [18]. Sixteen hybrids were prepared by reacting 5-amino-1-benzyl-3,3-dimethoxyindolin-2-one, benzyl isocyanide, carboxylic acids, and aldehyde/ketone derivatives, catalyzed by ZnF2

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

• mechanism is followed by 40% of the catalysed reactions studied. Mechanism 2 (Figure 5B) contains an additional step. In this mechanism, the epoxide is first isomerised through TS14, resulting in the formation of the aldehyde (Min4). It can be observed that the opening of the epoxide is catalysed by the

• presence of the CO2 adduct. In the gas phase and isolated, the isomerisation of the epoxide exhibits a barrier of 52.6 kcal·mol−1. In the case of F2_NB_H_H, the barrier is reduced to 37.0 kcal·mol−1. CO2 later reacts with the aldehyde, forming the insertion product already observed in mechanism 1 (Min2

The scent gland composition of the Mangshan pit viper, Protobothrops mangshanensis

• Jonas Holste,
• Paul Weldon,
• Donald Boyer and
• Stefan Schulz

Beilstein J. Org. Chem. 2024, 20, 2644–2654, doi:10.3762/bjoc.20.222

• the resulting solution was stirred for 1 h at that temperature. Aldehyde 3 (105 mg, 0.7 mmol) was added at −10 °C and stirred for a further 18 h. The reaction mixture was diluted with pentane and filtered. After the removal of the solvent, the crude product was purified by column chromatography using

Synthesis and cytotoxicity studies of novel N-arylbenzo[h]quinazolin-2-amines

• Battini Veeraiah,
• Kishore Ramineni,
• Dabbugoddu Brahmaiah,
• Nangunoori Sampath Kumar,
• Hélène Solhi,
• Rémy Le Guevel,
• Chada Raji Reddy,
• Frédéric Justaud and
• René Grée

Beilstein J. Org. Chem. 2024, 20, 2592–2598, doi:10.3762/bjoc.20.218

• afforded the known aldehyde 2 in 65% yield [13]. Then, reaction with guanidinium carbonate in DMA at high temperature [12], gave the desired intermediate 2-aminobenzo[h]quinazoline (3). In a final step, classical Buchwald–Hartwig coupling [14][15][16][17] with bromobenzene under the conditions described

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

• tolerated. This method leads to a variety of 2-substituted resorcin[n]arenes in a single synthetic step with isolated yields up to 98%. Keywords: cavitand; cyclization; HFIP; hydroxyalkylation; resorcinarenes; Introduction The acid-catalyzed aldehyde-resorcinol condensation has been studied for more than

• a century [1][2][3]. Decades of research culminated in the landmark paper by Niederl and Vogel [4], whose quantitative elementary analysis and molecular weight determinations led them to conclude that the most likely product of the aldehyde-resorcinol condensation was a four-fold species resulting

• presence of various aldehydes featuring different alkyl chains, all of which exhibited high isolated yields (Scheme 2, compounds 1a–e). Interestingly, literature reports commonly show lower yields as the aldehyde alkyl chain increases in length where commonly refluxing temperatures are required [9][74][76

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

• (Scheme 6). The study explored a broad range of p-methoxyphenyl (PMP)imines derived from aryl, heteroaryl and alkyl aldehydes (including ethyl glyoxylate), demonstrating yields of 57–98% and high enantioselectivity of 90–98%. Screening of aldehyde and amine components indicated that the method is

• slightly more efficient with electron-poor substrates. On the other hand, high enantioselectivity was maintained over the aldehyde scope regardless of steric size and position of the substituents. A few years later, Wulff and co-workers [42] further elaborated the aza-Cope rearrangement methodology by

• crystal XRD of the corresponding hydrochloride salt. Microwave-induced one-pot asymmetric allylation of in situ-formed arylimines, catalysed by (R)-3,3’-diphenyl-BINOL. Aldehyde and amine scope [26]. aThe reaction was conventionally heated at 50 °C for 24 hours instead of microwave irradiation. b1.0 equiv