Synthesis of diaryl phosphates using phytic acid as a phosphorus source

• Kazuya Asao,
• Seika Matsumoto,
• Haruka Mori,
• Riku Yoshimura,
• Takeshi Sasaki,
• Naoya Hirata,
• Yasuyuki Hayakawa and
• Shin-ichi Kawaguchi

Beilstein J. Org. Chem. 2026, 22, 213–223, doi:10.3762/bjoc.22.15

• -free synthetic methods have been reported for the synthesis of phosphorus compounds (Figure 2A) [35][36][37][38][39][40][41]. Cummins’s group demonstrated that phosphoric acid and condensed phosphoric acid can be reduced using trichlorosilane. The resulting intermediate, the bis(trichlorosilyl

• phosphoric acid and condensed phosphoric acid into a versatile PO2+ phosphorylation agent, (pyridine)2PO2[OTf]. The intermediate reacts with a variety of nucleophiles, providing a redox-neutral method for the flexible synthesis of P(V) compounds (Figure 2C) [44]. Furthermore, Naganawa’s group recently

• period for the formation of the phosphate monoester from phosphoric acid; however, an induction period associated with diester formation is observed between the formation of the monoester and the formation of intermediate DPpyP. This difference suggests that the monoester and the diester are formed via

Base-promoted deacylation of 2-acetyl-2,5-dihydrothiophenes and their oxygen-mediated hydroxylation

• Vladimir G. Ilkin,
• Margarita Likhacheva,
• Igor V. Trushkov,
• Tetyana V. Beryozkina,
• Vera S. Berseneva,
• Vladimir T. Abaev,
• Wim Dehaen and
• Vasiliy A. Bakulev

Beilstein J. Org. Chem. 2026, 22, 192–204, doi:10.3762/bjoc.22.13

• migration in the formed tetrahedral intermediate to afford formate ester; c) hydrolysis of the latter to form phenols [28]. The development of methods for the construction of heterocycles and their modification is an important area of organic synthesis [29]. Although the Dakin oxidation has become a

• elemental sulfur S6. Probably, the reaction is accompanied by the desulfurization of the oxidized intermediate, which causes the yellow color of the reaction solutions. The proposed mechanism for the developed transformations is depicted in Scheme 6. The reaction of dihydrothiophene 1a with sodium ethoxide

• led to the intermediate A. Elimination of ethyl/methyl acetate from intermediate A afforded anion B. The latter reacted in ethanolic solution with molecular oxygen [52] with the formation of peroxide anion C. The protonation of anion C with proton sources (residual water or/and solvent or 3a can serve

Improved synthesis and physicochemical characterization of the selective serotonin 2A receptor agonist 25CN-NBOH

• Adrian G. Rossebø,
• Hannah G. Kolberg,
• Anders E. Tønder,
• Louise Kjaerulff,
• Poul Erik Hansen,
• Karla A. Frydenvang,
• Jesper Østergaard and
• Jesper L. Kristensen

Beilstein J. Org. Chem. 2026, 22, 175–184, doi:10.3762/bjoc.22.11

• The synthesis of 1 starts from commercially available 2,5-dimethoxyphenethylamine (2C-H), which can be transformed into the intermediate 2C-CN, (Figure 1). We have previously reported high yielding 4-step procedure for this process, whereas the yield in the final step in the synthesis of 1 was a

• modest 65% [12]. In the present work, we found that simply adding 4 Å molecular sieves powder during the formation of the intermediate imine gave a much cleaner reaction and increased the yield of 1·HCl from 2C-CN·HCl to 74%. We suggest that the addition of the molecular sieves facilitates the formation

• of the required imine intermediate that upon reduction yields the desired product. The free base 1 was purified on normal-phase flash column chromatography, and 1·HCl was subsequently precipitated, providing a white crystalline solid (vide infra). Characterization of 25CN-NBOH·HCl (1·HCl) in the

A new synthesis of Tyrian purple (6,6’-dibromoindigo) and its corresponding sulfonate salts

• Holly Helmers,
• Mark Horton,
• Julie Concepcion,
• Jeffrey Bjorklund and
• Nicholas C. Boaz

Beilstein J. Org. Chem. 2026, 22, 167–174, doi:10.3762/bjoc.22.10

• purple, several syntheses of 1 have been reported in the literature [5]. As shown in Scheme 1A, a common route to 1 uses 4-bromo-2-nitrotoluene (3) as a key intermediate [5]. We were interested in a safe and cost-efficient synthesis of the major component of Tyrian purple that is amenable to generating

• similar analogues, using 3 as a key intermediate. Furthermore, we were interested in producing a water-soluble derivative of 1, much like indigo carmine was developed as a water-soluble derivative of indigo. Several syntheses of 3 have been reported, but the most common method involves the selective

• nitration of p-toluidine (2), followed by a Sandmeyer bromination [5][6][7][8][9]. While such chemistry is effective in smoothly generating 3 in good yield, this process requires the production of and use of a potentially explosive aryldiazonium intermediate [10]. Oxidation of the methyl group in 3 yields 4

Circumventing Mukaiyama oxidation: selective S–O bond formation via sulfenamide–alcohol coupling

• Guoling Huang,
• Huarui Zhu,
• Shuting Zhou,
• Wanlin Zheng,
• Fangpeng Liang,
• Zhibo Zhao,
• Yifei Chen and
• Xunbo Lu

Beilstein J. Org. Chem. 2026, 22, 158–166, doi:10.3762/bjoc.22.9

• -bromosuccinimide to generate a highly electrophilic sulfilimidoyl bromide intermediate R–S(Br)=N–C(O)R’, along with succinimide. The resulting S(IV)–Br species is then attacked by the alcohol 2, and nucleophilic substitution at sulfur followed by proton transfer furnishes the sulfinimidate ester 3 and HBr. The

Highly electrophilic, gem- and spiro-activated trichloromethylnitrocyclopropanes: synthesis and structure

• Ilia A. Pilipenko,
• Mikhail V. Grigoriev,
• Olga Yu. Ozerova,
• Igor A. Litvinov,
• Darya V. Spiridonova,
• Aleksander V. Vasilyev and
• Sergey V. Makarenko

Beilstein J. Org. Chem. 2026, 22, 123–130, doi:10.3762/bjoc.22.5

• to the bromonitroalkene afford the intermediate anion II, followed by tautomerization and formation of anion IV, which undergoes intramolecular nucleophilic substitution of the bromide along the C-alkylation pathway [37][38][39] (Scheme 6). The trans-configuration of the methine protons of the

• by BH+ from the side opposite to the –CH(EWG)2. Thus, only diastereomer III is formed. Deprotonation of this intermediate leads to carbanion IV. For further attack by the carbanion center to the carbon atom bonded to bromine, the –C(EWG)2 moiety must hold an anti-periplanar position relative to the

Total synthesis of natural products based on hydrogenation of aromatic rings

• Haoxiang Wu and
• Xiangbing Qi

Beilstein J. Org. Chem. 2026, 22, 88–122, doi:10.3762/bjoc.22.4

• process relies on the rapid interconversion of the enantiomers in the racemic substrate, which in turn relies on the acid-promoted isomerization between the aromatic indole and the nonaromatic exocyclic enamine intermediate. Very recently, Chen and co-workers reported that using a Mn catalyst with

• ]. Starting from compounds 77 and 78, Baldwin and co-workers converted them into pyridine derivative 79 in high yield over three steps including a Wittig reaction and tosylation. Subsequent reduction with sodium borohydride furnished the dimer 80 bearing partially reduced pyridine rings. From 80, intermediate

• , followed by hydrazinolysis to generate alcohol 120. Starting from the common intermediate 120, the total syntheses of renieramycin and lemonomycinone were accomplished through 11 and 13 steps, respectively. Total synthesis to the alkaloids GB13 by Sarpong, 2009 In 2009, Sarpong and co-workers reported a

Advances in Zr-mediated radical transformations and applications to total synthesis

• Hiroshige Ogawa and
• Hugh Nakamura

Beilstein J. Org. Chem. 2026, 22, 71–87, doi:10.3762/bjoc.22.3

• , Schwartz’s reagent reacts with triethylborane to generate a low-valent zirconium complex 5. This complex abstracts the halogen atom from the alkyl halide, forming alkyl radical 8. The radical then cyclizes onto the olefin, and the resulting radical intermediate undergoes hydrogen atom transfer (HAT) from

• , demonstrating excellent functional group tolerance. The proposed mechanism is shown in Scheme 2C. Zirconocene dichloride is first reduced by zinc dust to generate ZrII. The resulting low-valent zirconium species reacts with the alkyl iodide to form a metal-centered radical intermediate. This species undergoes

• its subsequent radical addition to 2-methylene-1,3-dithiane (14) proceeded, affording radical intermediate 15. This radical intermediate rapidly underwent homodimerization to give vic-bis(dithiane) 16. The reaction could be applied to both tertiary and secondary alkyl halides, providing the

Reactivity umpolung of the cycloheptatriene core in hexa(methoxycarbonyl)cycloheptatriene

• Dmitry N. Platonov,
• Alexander Yu. Belyy,
• Rinat F. Salikov,
• Kirill S. Erokhin and
• Yury V. Tomilov

Beilstein J. Org. Chem. 2026, 22, 64–70, doi:10.3762/bjoc.22.2

• excellent yield, the structure being confirmed using single crystal X-ray analysis (CCDC 2495984). Bromination afforded a mixture of symmetric cycloheptatriene 4b and norcaradiene 6b, while intermediate cycloheptatriene 5b was not even observed. Iodination gave exclusively norcaradiene 6c. Previously

• isomerization. However, these isomerizations are known to proceed as 1,5-sigmatropic shift [32] as observed in the formation of compounds 8 and 9, whereas the formation of products 4 through this pathway would require at least two consequent shifts. Thus, the absence of any intermediate-shift products along

Synthesis and applications of alkenyl chlorides (vinyl chlorides): a review

• Daniel S. Müller

Beilstein J. Org. Chem. 2026, 22, 1–63, doi:10.3762/bjoc.22.1

• to alkenyl chlorides with phosphorous pentachloride (PCl5): Friedel first reported the reaction of PCl5 with acetophenone (1) in 1868 (Scheme 1A) [45]. Treatment of the resulting intermediate 2 – then presumed to be a gem-dichloride – with aqueous KOH led to the formation of phenylacetylene (3). In

• dichloro intermediate 5 yielded the corresponding alkenyl chloride 6. In 1913, Faworsky revisited this transformation in an effort to prepare tetramethylallene (7) (Scheme 1C) [47]. However, several attempts to reproduce Henry’s procedure were unsuccessful. Instead, Faworsky isolated the α-chlorinated

• under the reaction conditions (acetate II). Subsequent addition of HCl to intermediate II generates chloride III, which undergoes elimination to yield the desired product IV. Kodomari and co-workers serendipitously discovered a related reaction in which a large excess of acetyl chloride (8 equivalents

One-pot synthesis of ethylmaltol from maltol

• Immanuel Plangger,
• Marcel Jenny,
• Gregor Plangger and
• Thomas Magauer

Beilstein J. Org. Chem. 2025, 21, 2755–2760, doi:10.3762/bjoc.21.212

• via methylation of a dianionic intermediate, proved unsuitable due to competing overalkylation and the necessity of sub-zero temperatures. In contrast, a transient protecting group approach enabled selective methylation under mild conditions. This culminated in a scalable, operationally simple one-pot

• through fermentation, or a synthetic intermediate derived thereof is being utilized. For example, the 1969 Pfizer patent describes the oxidation of kojic acid (3) with molecular oxygen to comenic acid, which is then decarboxylated to yield pyromeconic acid. An aldol addition with acetaldehyde followed by

• nucleophilicity of the intermediate lithium alkoxides and to the softer nucleophilic character at C vs O for lithium dienolates. While the dianion strategy was able to convert maltol (2) to ethylmaltol (1) in yields of up to 57%, the reactions suffered from an unsatisfactory purity profile. First, interconversion

Total synthesis of asperdinones B, C, D, E and terezine D

• Ravi Devarajappa and
• Stephen Hanessian

Beilstein J. Org. Chem. 2025, 21, 2730–2738, doi:10.3762/bjoc.21.210

• in the presence of the Pd catalyst. It follows that elimination and reduction must occur after Pd insertion and formation of a pallado–zinc intermediate which undergoes β-elimination and proton transfer. Seminal studies by Jackson [61] have reported related results with iodozinc N-Boc-ʟ-alanine

Competitive cyclization of ethyl trifluoroacetoacetate and methyl ketones with 1,3-diamino-2-propanol into hydrogenated oxazolo- and pyrimido-condensed pyridones

• Svetlana O. Kushch,
• Marina V. Goryaeva,
• Yanina V. Burgart,
• Marina A. Ezhikova,
• Mikhail I. Kodess,
• Pavel A. Slepukhin,
• Alexandrina S. Volobueva,
• Vladimir V. Zarubaev and
• Victor I. Saloutin

Beilstein J. Org. Chem. 2025, 21, 2716–2729, doi:10.3762/bjoc.21.209

• intermediate is aldol A, which is formed from 3-oxo ester 1 and methyl ketone 2 under the catalysis of amine 3 [24][25][29]. Therefore, we suggest that the formation of octahydropyrido[1,2-a]pyrimidinones 4 and hexahydrooxazolo[3,2-a]pyridones 5 proceeds via the initial formation of aldol A, which then reacts

• at the acyl moiety with the amino group of diamino alcohol 3 to generate a three-component intermediate B (Scheme 4). The latter undergoes intramolecular cyclization involving the C=N bond in two equally probable directions: by adding a free amino group to form a hexahydropyrimidine ring of

• intermediate C (path a), or by adding an OH group to generate an oxazolidine ring of intermediate D (path b). The subsequent intramolecular cyclization of intermediates C and D involving a secondary NH group and an ester substituent yields the bicycles 4 and 5, respectively (Scheme 4). In the reactions with

Mechanistic insights into hydroxy(tosyloxy)iodobenzene-mediated ditosyloxylation of chalcones: a DFT study

• Jai Parkash,
• Sangeeta Saini,
• Vaishali Saini,
• Omkar Bains and
• Raj Kamal

Beilstein J. Org. Chem. 2025, 21, 2703–2715, doi:10.3762/bjoc.21.208

• cationic intermediate which facilitates 1,2-aryl migration [20][21][22][23]. Similar types of oxidative rearrangements in α,β-unsaturated diaryl ketones that leads to the α-aryl-β,β dioxygenated skeleton via 1,2-aryl migration have been studied by using different reagents such as Tl(OCOCH3)3/CH3OH, Tl(ONO2

• HTIB leading to formation of ditosyloxy ketone may not occur at all [42]. The subsequent nucleophilic addition of −OTs on Int1 takes place on β-position specifically in a syn-manner with respect to the carbon–iodine bond. This nucleophilic syn-addition leads to the formation of an intermediate referred

• = -Cl, -NO2 would destabilize such an intermediate. Therefore, for chalcones with X = -Cl, -NO2 intermediate Int4 does not form. Hence, for chalcones with X = -OCH3, -SCH3 the reaction profile is: Reactants → Int1 → Int2 → Int3 → T.S. → Int4 → Int5 → β,β-ditosyloxy ketone (geminal product). while the

Tandem hydrothiocyanation/cyclization of CF₃-iminopropargyl alcohols with NaSCN in the presence of AcOH

• Ruslan S. Shulgin,
• Ol’ga G. Volostnykh,
• Anton V. Stepanov,
• Igor’ A. Ushakov,
• Alexander V. Vashchenko and
• Olesya A. Shemyakina

Beilstein J. Org. Chem. 2025, 21, 2694–2702, doi:10.3762/bjoc.21.207

• ][8]. However, this is mainly possible in the case of functionalized alkynes, where these intramolecular reactions usually involve other functional groups that are contained in the same intermediate. Among the numerous hydrofunctionalization reactions, hydrothiocyanation has attracted much attention

• thiocyanic acid at the triple bond – vinylthiocyanate A (Scheme 2). Isothiazolium thiocyanate 2 is formed by the attack of the imino nitrogen atom on the sulfur atom and the elimination of the CN anion in the Z-isomer of intermediate A. On the other hand, intramolecular addition of the hydroxy group to the

Recent advancements in the synthesis of Veratrum alkaloids

• Morwenna Mögel,
• David Berger and
• Philipp Heretsch

Beilstein J. Org. Chem. 2025, 21, 2657–2693, doi:10.3762/bjoc.21.206

• group in the sequence to temporarily mask that specific group and its reactivity. The latter are considered undesirable transformations, since they do not contribute to advancing the complexity of the synthetic intermediate toward the target and should therefore be avoided, or at least minimized in use

• –halogen exchange in the ABC-fragment 38 followed by 1,2-addition to the ketone moiety in the F-ring fragment 42. Protection group manipulations allowed for the union of both fragments to advanced intermediate 43 in three steps in 42%, setting the stage for the key cyclization reactions in this sequence

• , with the hydroxy group at C17 playing a crucial role trapping a cationic intermediate from this rearrangement. Starting point in this synthesis is again dehydroepiandrosterone (24), which was protected in 3-position with an acetyl group (Scheme 12). A copper-mediated C–H activation procedure to obtain

Synthesis of new tetra- and pentacyclic, methylenedioxy- and ethylenedioxy-substituted derivatives of the dibenzo[c,f][1,2]thiazepine ring system

• Gábor Berecz,
• András Dancsó,
• Mária Tóthné Lauritz,
• Loránd Kiss,
• Gyula Simig and
• Balázs Volk

Beilstein J. Org. Chem. 2025, 21, 2645–2656, doi:10.3762/bjoc.21.205

• amidation (48), N-methylation (49), and hydrolysis (50), as well as the direct amidation of 47 to 49 worked well, the Friedel–Crafts cyclization via the corresponding acyl chloride to the tetracyclic key intermediate 51 could only be carried out with 26% yield, obviously because of incomplete

Chemoenzymatic synthesis of the cardenolide rhodexin A and its aglycone sarmentogenin

• Fuzhen Song,
• Mengmeng Zheng,
• Dongkai Wang,
• Xudong Qu and
• Qianghui Zhou

Beilstein J. Org. Chem. 2025, 21, 2637–2644, doi:10.3762/bjoc.21.204

• donor, through a late-stage glycosylation. The aglycon 2 can be derived from the Δ14 olefin intermediate 3 via Mukaiyama hydration and several functional group transformations. In turn, 3 would be generated from the key C14α-hydroxylated intermediate 4 via an elimination process. For the synthesis of 4

• started the first step to prepare the C14α-hydroxylated steroidal intermediate 4 from 17-deoxycortisone (5). Delightfully, based on our previous study on enzymatic α-hydroxylation of C14–H of common steroids [27], compound 4 could be successfully obtained in 69% yield by using the biocatalyst CYP14A

• transforming it into the pivotal C14 β-hydroxylated steroidal intermediate. As shown in Scheme 2, a BF3·Et2O-promoted elimination afforded the 14-olefinated intermediate 3 in a moderate yield. However, the following Mukaiyama hydration to introduce the C14 β-hydroxy group was unsuccessful. Owing to the

Thiazolidinones: novel insights from microwave synthesis, computational studies, and potentially bioactive hybrids

• Luan A. Martinho,
• Victor H. J. G. Praciano,
• Guilherme D. R. Matos,
• Claudia C. Gatto and
• Carlos Kleber Z. Andrade

Beilstein J. Org. Chem. 2025, 21, 2618–2636, doi:10.3762/bjoc.21.203

• aldehyde 1, activated by protonation of the oxygen atom through structure ii, forming the intermediate aldol iii. In the presence of EDDA, water elimination occurs in intermediate iv, yielding the Knoevenagel adducts 3 or 4. Synthesis of novel imidazo[1,2-a]pyridine–thiazolidinone hybrids To further

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

• of single-electron NHC catalysis by incorporating oxidatively generated aryloxymethyl radicals A as a key intermediate. A variety of γ-aryloxy ketones 12 were successfully prepared in the presence of NHC (15 mol %), photocatalyst (2 mol %), using 467 nm LED and a combination of alkene 11, amide 9

• cleavage and the new C–O bond formation process were achieved using NHC (10 mol %), a photocatalyst (2 mol %), and DABCO (1.5 equiv), providing the corresponding aryl salicylates 27 in moderate to good yields. Mechanistic studies support the oxidation of the Breslow intermediate by oxygen in the presence

Recent advances in total synthesis of illisimonin A

• Juan Huang and
• Ming Yang

Beilstein J. Org. Chem. 2025, 21, 2571–2583, doi:10.3762/bjoc.21.199

• migrations. The 5/6/6 tricarbocyclic allo-cedrane framework 6 serves as the key biogenetic intermediate for both the seco-prezizaane and illismonane skeletons. The conversion of the allo-cedrane skeleton to the illismonane skeleton was hypothesized to proceed via a 1,2-alkyl migration of intermediate 9 to 10

• . However, subsequent density functional theory (DFT) calculations by the Tantillo group on rearrangements of potential biosynthetic precursors revealed that structure 10 corresponds to a transition state rather than a stable intermediate of the 1,2-alkyl migration [27]. Their study further indicated that

• rearrangement of 28 enabled the rearrangement of cis-pentalene to trans-pentalene, delivering intermediate 29, which possesses the same carbon skeleton as the natural product. Further oxidation of the primary alcohol to a carboxylic acid, accompanied by TBS deprotection, afforded hemiketal 30. Finally, a White

Total syntheses of highly oxidative Ryania diterpenoids facilitated by innovations in synthetic strategies

• Zhi-Qi Cao,
• Jin-Bao Qiao and
• Yu-Ming Zhao

Beilstein J. Org. Chem. 2025, 21, 2553–2570, doi:10.3762/bjoc.21.198

• intermediate, systematically deriving multiple structurally related natural products through functional group transformations and oxidation-state adjustments [3][4]. This approach efficiently constructs compound family libraries, greatly facilitating drug screening and structure–activity relationship (SAR

• is as follows: Starting from the chiral compound (S)-carvone, four simple transformations yield the enone intermediate 11. This intermediate undergoes an intermolecular [4 + 2] cycloaddition with diene 12, generating two sets of regioselective products in an approximate ratio of 1:1. The product with

• the correct relative configuration undergoes hydrolysis of its spirocyclic lactone moiety under basic conditions to yield 13, establishing the critical C5 chiral center. Under acidic conditions, intermediate 13 undergoes ketal deprotection followed by successive intramolecular aldol reactions

Rapid access to the core of malayamycin A by intramolecular dipolar cycloaddition

• Yilin Liu,
• Yuchen Yang,
• Chen Yang,
• Sha-Hua Huang,
• Jian Jin and
• Ran Hong

Beilstein J. Org. Chem. 2025, 21, 2542–2547, doi:10.3762/bjoc.21.196

• intermediate 5 will be converted into the final target after installation of the urea and uracil motifs. Accordingly, a nitrone-based latent functionality approach [28] would be tunable from fully substituted tetrahydrofuran-derived nitrone 7. The cis-1,2-hydroxy amine could be derived from oxazoline 6 through

• cleavage of the N–O bond, oxidation and Baeyer–Villiger oxidation. The starting functional groups (including alkyne and nitrone) for the proposed oxazoline were established in literature precedents [29][30][31]. Moreover, the readily available intermediate 8 [32] bearing three defined stereogenic centers

• formyloxy group on the N atom in the unstable intermediate 13 serves as electron-withdrawing group to facilitate fragmentation when removal of the acidic proton at C2 was initiated. Although the reduction of enone 14 could provide the requisite stereoisomer, the rigid conformation of such bicyclic [4.3.0

Assembly strategy for thieno[3,2-b]thiophenes via a disulfide intermediate derived from 3-nitrothiophene-2,5-dicarboxylate

• Roman A. Irgashev

Beilstein J. Org. Chem. 2025, 21, 2489–2497, doi:10.3762/bjoc.21.191

• ]. In route IV, cleavage of the ethyl xanthate group in the starting substrate by NaOMe generates a thiolate intermediate, which undergoes S-alkylation and subsequent NaOMe-promoted cyclization to afford the 3-hydroxy-TT [28]. In our recent works, it was presented an effective strategy for synthesizing

• subsequent fate of the intermediate appears to be critical. Based on our observations and literature data, a probable reaction mechanism was proposed. The initial nucleophilic substitution of the nitro group in ester 1 by the AcS− anion yields the S-acetyl derivative (intermediate A) and NO2− anion. The key

• step leading to the observed products is the reaction of the S-acetyl intermediate A with the generated NO2− anion, resulting in the formation of a thiophene-3-thiolate species (intermediate B) and acetyl nitrite. Thiolate B then acts as a nucleophile toward starting ester 1, resulting in the formation

Palladium-catalyzed regioselective C1-selective nitration of carbazoles

• Vikash Kumar,
• Jyothis Dharaniyedath,
• Aiswarya T P,
• Sk Ariyan,
• Chitrothu Venkatesh and
• Parthasarathy Gandeepan

Beilstein J. Org. Chem. 2025, 21, 2479–2488, doi:10.3762/bjoc.21.190

• after 2 hours, indicating that C–H bond cleavage is kinetically relevant and likely involved in the rate-determining step (Scheme 5b). To gain additional mechanistic insight, we synthesized palladacycle intermediate 6 following the reported procedure [58]. Then, the reaction was carried out using

• palladacycle 6 as the catalyst, and the desired nitrated product 2a was obtained in 48% yield (Scheme 5c). This result supports the involvement of palladacycle intermediate 6 in the catalytic cycle. Proposed mechanism Based on our experimental results and related literature precedents [68][69][74][75][76][77

• a six-membered palladacycle intermediate 9. Subsequent reaction with in situ-generated HNO3 facilitates nitro group incorporation to form the C1-nitrated carbazole product 2a and regeneration of the active palladium catalyst 7, thereby completing the catalytic cycle. Conclusion In summary, we have