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

• alkyltrifluoroborate into its corresponding alkyl radical. o-Halo-substituted aryl selenides and sulfides 13 can be achieved by a three-component coupling reaction performed with an aryne precursor, potassium halides and electrophilic chalcogen species as reactants, in the presence of Cu(OTf)2 (Scheme 10) [23]. Under

Facile one-pot reduction of β-nitrostyrenes to phenethylamines using sodium borohydride and copper(II) chloride

• Laura D’Andrea and
• Simon Jademyr

Beilstein J. Org. Chem. 2025, 21, 39–46, doi:10.3762/bjoc.21.4

• test the potential effects on halogenated aromatic structures and no dehalogenation was detected up to 24 hours stirring. The retention of halogen atoms on aryl halides distinguishes this procedure from traditional techniques, such as those involving LiAlH4, which can cause dehalogenation [30][31]. The

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

Giese-type alkylation of dehydroalanine derivatives via silane-mediated alkyl bromide activation

• Perry van der Heide,
• Michele Retini,
• Fabiola Fanini,
• Giovanni Piersanti,
• Francesco Secci,
• Daniele Mazzarella,
• Timothy Noël and
• Alberto Luridiana

Beilstein J. Org. Chem. 2024, 20, 3274–3280, doi:10.3762/bjoc.20.271

• , alkyl radicals have been produced from alkyl halides, using azobisisobutyronitrile (AIBN) as initiator, promoting a tin-mediated XAT (Figure 1a) [8][9]. However, tin-based compounds are highly toxic and require harsh conditions for the initiation event. Fortunately, a renaissance in the field of

• photocatalytic activation (Figure 1b) [17][18][19][20][21]. A photocatalytic HAT or SET generates the corresponding boryl, α-amino or silyl radical, which can abstract a halogen atom from alkyl halides to form the corresponding alkyl radical. However, the use of TTMS as a XAT reagent had already been established

• photocatalyst (Figure 1d) [25]. Noël et al. [26] have further extended this approach to include alkyl bromides (Figure 1e) [26]. Despite the effectiveness of the photolysis, benzophenone derivatives have also been shown to enhance the productivity of silane-mediated conjugate additions, using alkyl halides [27

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

• those that lead to α-alkyl-substituted compounds, is still challenging [27]. For example, in the SN2 reaction of alkyl halides with sulfoxonium ylides, the initially formed α-alkyl-substituted ylide reacts further with the halide to expel the sulfoxide and ultimately generate an α-halogenated product

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

• giving a stabilized benzyl radical D, which recombines with tert-butylperoxy radical C to give the target product 179. Later, this approach was modified and extended to various alkyl halides. Diverse α-peroxy-β-substituted ethylbenzene products 181 were prepared from styrenes 180, TBHP and alkyl halides

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

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

• organolithium reagents, thus limiting functional-group tolerance [11][12][13]. By contrast, heteroleptic (mixed) alkylzinc species (i.e., RZnX) are readily available and can typically be prepared from alkyl halides by direct insertion of metallic zinc into the carbon–halogen bond [14][15][16][17][18][19][20][21

• , we reasoned that replacing alkyl iodides by alkyl bromides could be relevant to the field due to interesting assets such as better availability and lower cost of the parent alkyl halides. Results and Discussion We investigated new conditions that would allow for the synthesis of mixed alkylzinc

• 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

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

• reported over the years (Figure 2) [2]. Conventionally, benzophenones are synthesized by Friedel–Crafts acylation of benzoyl halides and aromatic compounds. However, the regioselectivity of Friedel–Crafts benzoylation at the desired position is difficult to control [9]. On the other hand, 2

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

• cathodic reduction and to prevent the reoxidation of the reduced SO2 at the anode, a divided cell setup is required (Scheme 12). C–H bond halogenation: Aryl and alkyl halides are important synthetic building blocks for cross-coupling reactions as well as bioactive molecules with applications in

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

• halogenated pyrans reveals deviation in the intra-annular torsion angles arising from repulsion between the axial fluorine at C2 and the axial halogen at C4, which increases with the size of the halogen at C4 (F < Cl < Br < I). Crystal packing arrangements of pyran inter-halides show hydrogen bond acceptor

• chiral halides: F, Cl, Br, I) [19]. Only a handful of natural product syntheses have been reported [20][21], despite the promising biological activity of these unique inter-halides [22]. For our part, we recently reported the synthesis of contiguous inter-halide-bearing stereocenters using a Chiron

• 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

Phenylseleno trifluoromethoxylation of alkenes

• Clément Delobel,
• Armen Panossian,
• Gilles Hanquet,
• Frédéric R. Leroux,
• Fabien Toulgoat and
• Thierry Billard

Beilstein J. Org. Chem. 2024, 20, 2434–2441, doi:10.3762/bjoc.20.207

• compounds from alkenes and DDPyOCF3, more precisely to α-trifluoromethoxylated, β-phenylselenylated compounds. Results and Discussion The electrophilic addition of phenylselenyl halides to alkenes to form a selenonium intermediate that can be intercepted by an external nucleophile is a well-known method to

Facile preparation of fluorine-containing 2,3-epoxypropanoates and their epoxy ring-opening reactions with various nucleophiles

• Yutaro Miyashita,
• Sae Someya,
• Tomoko Kawasaki-Takasuka,
• Tomohiro Agou and
• Takashi Yamazaki

Beilstein J. Org. Chem. 2024, 20, 2421–2433, doi:10.3762/bjoc.20.206

• shorter period possibly because of its significantly high electrophilicity by the attachment of three strongly electron-withdrawing moieties. Reactions of (E)-3-Rf-2,3-epoxypropanoates 2 with amines, thiols, and metal halides Because the epoxide ring opening is known to occur in an SN2 fashion, compounds

• executed at −78 °C under the action of LDA [29]. Moreover, by using the epoxyester 2b as the representative substrate, clarification of its reactivity was carried out by mixing with 1) heteronucleophiles like amines, thiols, and magnesium halides, 2) softer carbon nucleophiles such as malonates, and 3

Evaluating the halogen bonding strength of a iodoloisoxazolium(III) salt

• Dominik L. Reinhard,
• Anna Schmidt,
• Marc Sons,
• Julian Wolf,
• Elric Engelage and
• Stefan M. Huber

Beilstein J. Org. Chem. 2024, 20, 2401–2407, doi:10.3762/bjoc.20.204

• obtained: in a titration study by Mayer and Legault it was determined that cyclic five-membered DAI salts, so-called iodolium compounds, are significantly stronger Lewis acids than their less-stable acyclic counterparts [12]. By using the activation of alkyl halides as a benchmark, our group later reported

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

• diarylacetic acids from diarylmethanol species and carbon dioxide without transformation of the hydroxy group into appropriate leaving groups, such as halides and esters including carbonates. Keywords: C(sp3)–O bond cleavage; diarylacetic acid; diarylmethanol; electrochemical reduction; fixation of carbon

Electrochemical allylations in a deep eutectic solvent

• Sophia Taylor and
• Scott T. Handy

Beilstein J. Org. Chem. 2024, 20, 2217–2224, doi:10.3762/bjoc.20.189

• product, although in this case, reduction of the nitro group to an amino group was observed and the resulting 4-aminobenzaldehyde is likely too electron-rich to undergo allylation. The use of other halides was also explored (Table 3). Switching to allyl chloride (Table 3, entry 2) did result in partial

• more substituted end (gamma addition) was the major product in both cases, although alpha addition was also observed. In the case of crotyl bromide, no diastereoselectivity was noted for the gamma product. Non-allylic halides such as benzyl bromide, propargyl bromide, and ethyl bromoacetate (Table 3

Efficacy of radical reactions of isocyanides with heteroatom radicals in organic synthesis

• Akiya Ogawa and
• Yuki Yamamoto

Beilstein J. Org. Chem. 2024, 20, 2114–2128, doi:10.3762/bjoc.20.182

• the combination with groups 15–17 interelement compounds would be considered effective for the generation of groups 13 and 14 heteroatom radicals. Radical addition of group 17 compounds to isocyanides If isocyanides (RNC) can undergo a radical addition of hydrogen halides (HX) and molecular halogens

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

• from di-tert-butyldiazocarboxylate (23), aryl-substituted di-Boc-hydrazines 26 were prepared by the addition of aryllithium species generated in situ by lithium-halogen exchange of aryl halides [55]. Gerstenberger et al. used this entry for the one-pot synthesis of N-arylpyrazoles 25, as depicted in

• . In cases where the α,β-unsaturated carbonyl compounds contain a heteroatom in the β-position, aromatization is triggered by elimination under redox-neutral conditions. Tasch et al. successfully coupled aryl halides with α-bromocinnamaldehyde (51) using a Masuda borylation Suzuki cross-coupling (MBSC

• ) [69] approach without reducing the reactivity of the Michael system. In this one-pot procedure, the borylation of aryl halides with pinacolborane gives aryl pinacolyl boronates 53, which are then coupled with bromoenal 51 to generate the intermediary enal 54. Subsequent cyclization with tosylhydrazine

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

• electrochemical approach constitutes an advantageous alternative to previous methods, which required the preparation of difficult-to-handle hydrazonoyl halides for the synthesis of 1-aryl-5-amino-1,2,4-triazoles from cyanamide [56][57]. Pyrazolines are highly important heterocyclic motifs in pharmaceutical and

• agrochemical industries. The (3 + 2)-cycloaddition between nitrile imines and alkenes represents one of the most efficient strategies to prepare these azacycles. However, conventional methods for the generation of the nitrile imine involved the use of unstable hydrazonoyl halides or the oxidation of aldehyde

Radical reactivity of antiaromatic Ni(II) norcorroles with azo radical initiators

• Siham Asyiqin Shafie,
• Ryo Nozawa,
• Hideaki Takano and
• Hiroshi Shinokubo

Beilstein J. Org. Chem. 2024, 20, 1967–1972, doi:10.3762/bjoc.20.172

• benzoyl peroxide, TEMPO, and the combination of alkyl halides with BEt3, were not applicable to this reaction. Physical properties The electronic absorption spectra of norcorrole 1 and adduct 2a are shown in Figure 3. While norcorrole 1 exhibited a weak absorption band from 600 nm to the NIR region, due

Negishi-coupling-enabled synthesis of α-heteroaryl-α-amino acid building blocks for DNA-encoded chemical library applications

• Matteo Gasparetto,
• Balázs Fődi and
• Gellért Sipos

Beilstein J. Org. Chem. 2024, 20, 1922–1932, doi:10.3762/bjoc.20.168

• heteroaromatic halides. The reaction sequence utilizes a photochemically enhanced Negishi cross-coupling as a key step, followed by oximation and reduction. The prepared amino esters were validated for on-DNA reactivity via a reverse amidation–hydrolysis–reverse amidation protocol. Keywords: amino acids; DEL

• , Alcazar et al. developed continuous flow protocols for both the generation of alkylzinc halides and for the subsequent Negishi cross-coupling reaction [40][41][42][43][44]. We successfully adapted Alcazar’s protocols for the synthesis of otherwise challenging heteroaryl–alkyl connections (see Table S1 in

• carbonyl group to an oxime through condensation with hydroxylamine (Scheme 5, bottom) [62][63][64]. In order to develop a synthetic approach applicable to several different substrates, we decided to screen the three methods on one example from each type of heteroaryl halides. According to our experimental

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

Oxidation of benzylic alcohols to carbonyls using N-heterocyclic stabilized λ³-iodanes

• Thomas J. Kuczmera,
• Pim Puylaert and
• Boris J. Nachtsheim

Beilstein J. Org. Chem. 2024, 20, 1677–1683, doi:10.3762/bjoc.20.149

• ). At this temperature, the reaction time was significantly reduced to 2.5 h. A variety of other additives were tested next, revealing TsOH or NaOTs inhibiting the reaction (Table 1, entries 2 and 3). The addition of tetrabutylammonium halides showed the chloride salt being superior, giving comparable

Divergent role of PIDA and PIFA in the AlX₃ (X = Cl, Br) halogenation of 2-naphthol: a mechanistic study

• Kevin A. Juárez-Ornelas,
• Manuel Solís-Hernández,
• Pedro Navarro-Santos,
• J. Oscar C. Jiménez-Halla and
• César R. Solorio-Alvarado

Beilstein J. Org. Chem. 2024, 20, 1580–1589, doi:10.3762/bjoc.20.141

• straightforward conditions (Scheme 1). The synthesis of aryl halides is of great academic and industrial importance. Recently, our research group has developed a new procedure for the ortho-selective chlorination of phenols under mild conditions in a short reaction time [26]. The chlorinating species was

Electrocatalytic hydrogenation of cyanoarenes, nitroarenes, quinolines, and pyridines under mild conditions with a proton-exchange membrane reactor

• Koichi Mitsudo,
• Atsushi Osaki,
• Haruka Inoue,
• Eisuke Sato,
• Naoki Shida,
• Mahito Atobe and
• Seiji Suga

Beilstein J. Org. Chem. 2024, 20, 1560–1571, doi:10.3762/bjoc.20.139

• aryl halides [42]. PEM reactors are also gaining industrial attention. Weber et al. reported a series of large-scale syntheses using PEM reactors [43]. We studied electrochemical transformations [44][45][46][47][48][49] and recently reported the selective reduction of enones using a PEM reactor [50