The trans-influence in gold chemistry from a catalytic perspective

• Manfred Bochmann

Beilstein J. Org. Chem. 2026, 22, 838–856, doi:10.3762/bjoc.22.66

• ligands is to consider the structure of the recently described π-allyl complexes 26–28 (Scheme 14) [80][81][82][83]. Compounds 26 and 27 were characterised by X-ray diffraction and NMR spectroscopy, which showed that 26 is fluxional. The dication 28 was spectroscopically identified and the structure

• optimised by DFT calculations [82]. They clearly fall into two categories: In the C^N and P^N compounds the allyl bonding is very asymmetrical, with a long and a short C–C bond and strong variations in Au–C bond distances, as expected for a σ,π-allyl, while in 27 and its methallyl analogue the bonding is

• bonds. Alkyne, alkene and isocyanide hydroauration by a bimolecular gold radical mechanism [49][65][66]. Reactions of (C^C)Au–H with DMAD [50]. Alkyne hydroauration by a bimolecular Au(III)–Au(I)-assisted process [69]. Gold(III) π-allyl complexes. Outer-sphere mechanism of ethylene insertion into Au–O

Synthesis of heterocycles based on azomethine ylides from α-amino acids (or amines) and carbonyl compounds

• Ekaterina V. Berezhnaya,
• Alexander I. Ponyaev,
• Vitali M. Boitsov and
• Alexander V. Stepakov

Beilstein J. Org. Chem. 2026, 22, 705–741, doi:10.3762/bjoc.22.55

Modern synthetic pathways towards eribulin and its subunits

• Sebastian Dominik Graf

Beilstein J. Org. Chem. 2026, 22, 495–526, doi:10.3762/bjoc.22.37

• described in Scheme 6 below (R1 and R2 in equatorial position). From 43, the methylene unit in 44 was formed by Pd(0)-mediated generation of a π-allyl–palladium intermediate, followed by reductive termination (Tsuji-reduction), alongside the substrate-controlled alignment of the adjacent methyl substituent

• under basic conditions triggered an Achmatowicz rearrangement (shown in Scheme 8, below) to assemble a hydropyranone ring [83]. Eventual acetylation of the free alcohol units afforded 70 in 3:1 dr. C-Glycolysation with allyl-TMS and oxidative cleavage of the PMB moiety yielded 71. The stereochemistry of

• in 71% yield. A detailed mechanism for this transformation is shown in Scheme 24 below [98]. Here, the Rh(II)-induced elimination of N2 generates carbene 218, which is attacked by the adjacent allyl ether moiety to form unstable zwitterion 219. Sigmatropic rearrangement and acidic workup yielded 213

Synthesis and stereochemical analysis of dynamic planar chiral oxa[7]orthocyclophene

• Yukiho Hashimoto,
• Yuuya Kawasaki,
• Kazunobu Igawa and
• Katsuhiko Tomooka

Beilstein J. Org. Chem. 2026, 22, 436–442, doi:10.3762/bjoc.22.30

• of propargyl alcohol 3 and the alkyne moiety in 3 can be introduced by an alkynylation of the formyl group of aldehyde 4. Thus, we started this synthesis from O-protected 2-bromobenzyl alcohol derivative 5 for the introduction of the propanal moiety of 4 by a Heck reaction with allyl alcohol. The

• synthetic route for the C6-iodo-substituted 1ad is shown in Scheme 2. The Heck reaction of O-TIPS-protected 5a with allyl alcohol in the presence of a palladium catalyst provided the aldehyde 4a in 78% yield [9]. The reaction of 4a with CBr4 and PPh3, followed by treatment with n-BuLi, afforded the terminal

Dialkylaminoalkylation of β-ketosulfones via ring-opening of 3-sulfonylpyrrolidines

• Evgeny M. Buev,
• Alexander V. Pavlushin,
• Vladimir S. Moshkin and
• Vyacheslav Y. Sosnovskikh

Beilstein J. Org. Chem. 2026, 22, 383–389, doi:10.3762/bjoc.22.26

• -1-amines 4c–e,h were isolated in 40–69% yields (Scheme 2). Introduction of the m-nitro substituent led to partial resinification during the ring-cleavage step and significant decrease in the reaction outcome (products 4f,g). We have demonstrated that ethyl bromide, benzyl chloride, allyl bromide

Arene activation via π-bond localization: concepts and opportunities

• Paul Meiners,
• Julian J. Melder and
• Tobias Morack

Beilstein J. Org. Chem. 2026, 22, 257–273, doi:10.3762/bjoc.22.19

• principal platforms. Distinct from their η3-allyl counterparts, which readily isomerize between σ (η1) and π (η3) coordination, the η3-benzyl motif demands partial disruption of aromatic stabilization – an energetic penalty that must be compensated by the metal–ligand interaction (Scheme 5A). This challenge

• process. Subsequent computational studies, however, refined this mechanistic understanding, revealing that reductive elimination proceeds through coupling of the C(3) terminus of the η1-allyl fragment with the para-carbon of the η3-benzyl ligand (Scheme 6A, right) [75]. Together, these insights

• transformation of allyl chloride-substituted naphthalenes and phenanthrenes in the selective coupling with allylstannanes to deliver the corresponding ortho-allylated products [84]. Subsequently, Bao and co-workers extended this concept to encompass allenylstannanes, thereby accessing the propargylated analogues

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

• anionic system (shown as tautomer in Figure 2) with a diene fragment (shown as double bonds) twisted over it. In hexa(methoxycarbonyl)cycloheptatrienyl anion 2 the prevalent allylic conformer is the one with the hydrogen atom in the middle of the allyl-anionic fragment (the i-position) to afford the

• the set of conformations of anion 2 and found that conformer 2', with an allyl-anionic fragment shifted to form a nucleophilic CH fragment (Figure 3), is only 9.6 kcal/mol less stable than the main conformer 2 (the energy values of other conformers are given in Supporting Information File 1). Note

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

• initiated by the activation of allyl bromide using InCl3 (Scheme 48C) [158]. Very likely the first step involves the generation of allyl cation I by activation of the allyl bromide with InCl3. Subsequent trapping by the appended alkyne will form alkenyl cation II. Cation II then reacts with dichloromethane

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

• the presence of the N-pivaloyl group led to the same mixture of isomers. Numerous conditions to change the ratio were not successful [36] (Supporting Information File 1, Table S1). In view of the above mentioned issues, we considered chemically more challenging protocols starting with allyl- or

• presence of the allyl or propenyl group at different positions does not appear to affect the yields (Scheme 6). Importantly, it was observed that reduction and β-elimination of the organozinc reagent prepared from 29 took place during the cross-coupling reaction, thereby affecting the yield (Scheme 7) [60

• prenylindole alkaloids derived from tryptophan. Representative retrosynthetic considerations for 7-prenyl- and 7-allyltryptophan. Negishi cross-coupling of allyl- and prenyl(iodo)indoles. C-7 Functionalization of 7-iodo-Nα-Boc-tryptophan methyl ester. C-7 Prenylation via C–H activation. Synthesis of prenyl

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

• transpositions [31]. Starting from (S)-carvone (67), reaction with allyl bromide introduced an allyl group to give 68, which was then converted to the bicyclic compound 69 via a ring-closing metathesis (RCM) reaction followed by one-pot epimerization at the α-position of the carbonyl group (Scheme 7

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

• -alkoxy bridgehead radical addition then installed an allyl fragment, and ring-closing metathesis (RCM) smoothly formed the C ring to complete the core skeleton. The total synthesis was finalized by installing the four remaining stereocenters (C2, C3, C9, and C10). The specific synthetic route is as

• hemiacetalization to construct the oxa[3.2.1]-bridged ring system, thereby forming the D and E rings. Subsequently, the introduction of a tertiary hydroxy thiocarbonate at C11 afforded compound 38. Under thermal conditions, 38 underwent smooth introduction of an allyl fragment via intermolecular radical addition

• reaction with allyltributylstannane, yielding compound 40. After isomerization of the C11 allyl double bond and introduction of a C6 isobutenyl group, the resulting diene 42 underwent RCM catalyzed by the Hoveyda–Grubbs catalyst to form the pentacyclic skeleton 43, thus completing the C ring of the natural

Ni-promoted reductive cyclization cascade enables a total synthesis of (+)-aglacin B

• Si-Chen Yao,
• Jing-Si Cao,
• Jian Xiao,
• Ya-Wen Wang and
• Yu Peng

Beilstein J. Org. Chem. 2025, 21, 2548–2552, doi:10.3762/bjoc.21.197

• cyclization, and a subsequent acetal reduction under acidic conditions then can complete the total synthesis of this molecule. The cyclization precursor 5 could be prepared from the primary alcohol 6 through transforming functional groups of the alkyl chain and installing an allyl group. It was envisioned

• 2,4,4,6-tetrabromo-2,5-cyclohexadienone (TBCD) in CH2Cl2 followed by reaction with allyl alcohol, provided β-bromo acetal 5 in 30% overall yield starting from alcohol 6. With a successful preparation of the cyclization precursor 5, the designed nickel-promoted reductive tandem cyclization was pursued

• of (+)-aglacin B, a typical aryltetralin natural product [23][24], was completed from 2,6-dimethoxyphenol. The key Ni-promoted reductive cyclization cascade of a β-bromo acetal with an allyl tether, smoothly established the tetrahydronaphtho[2,3-c]furan core of this molecule in a new fashion. The

Isoorotamide-based peptide nucleic acid nucleobases with extended linkers aimed at distal base recognition of adenosine in double helical RNA

• Grant D. Walby,
• Brandon R. Tessier,
• Tristan L. Mabee,
• Jennah M. Hoke,
• Hallie M. Bleam,
• Angelina Giglio-Tos,
• Emily E. Harding,
• Vladislavs Baskevics,
• Martins Katkevics,
• Eriks Rozners and
• James A. MacKay

Beilstein J. Org. Chem. 2025, 21, 2513–2523, doi:10.3762/bjoc.21.193

• incomplete conversion resulted in Boc protected beta-alanine that was challenging to separate from the desired product (3). Carboxylic acid 3 then underwent a peptide coupling reaction with allyl-protected PNA backbone 4 to afford nitrobenzene 5 in 69% yield. Nitrobenzene 5 was then reduced to the

• % of the final desired monomer 8 was also isolated in the coupling step, presumably due to hydrolysis of the allyl ester in the iron reduction step. The remaining allyl ester 7 was deallylated via Pd(PPh3)4 to afford the monomer 8 in 51% yield. Db2 Synthesis Db2 was prepared through a convergent

Catalytic enantioselective synthesis of selenium-containing atropisomers via C–Se bond formations

• Qi-Sen Gao,
• Zheng-Wei Wei and
• Zhi-Min Chen

Beilstein J. Org. Chem. 2025, 21, 2447–2455, doi:10.3762/bjoc.21.186

• efficiently constructed by catalytic asymmetric hydroselenation, catalytic asymmetric allyl substitution, catalytic asymmetric electrophilic selenylation/cyclization, etc. The research content of this part has already been covered by relevant reviews [15][16][17], so it is not within the scope of discussion

Pd-catalyzed dehydrogenative arylation of arylhydrazines to access non-symmetric azobenzenes, including tetra-ortho derivatives

• Loris Geminiani,
• Kathrin Junge,
• Matthias Beller and
• Jean-François Soulé

Beilstein J. Org. Chem. 2025, 21, 2234–2242, doi:10.3762/bjoc.21.170

• (allyl)]2, XPhos, t-BuONa in 1,2-dimethoxyethane (DME)) [55]. The reaction outcomes were analyzed with both GC/MS and GC/FID analysis. Under these conditions, we were pleased to find that 1-phenyl-2-(o-tolyl)diazene (3a) was obtained with a GC yield of 50% (Table 1, entry 1). While all starting materials

• (allyl)2 in DME with strong base (Cs2CO3) favors C–N-bond coupling, which may yield products resulting from arylation at either the terminal or internal nitrogen atoms. The selectivity can be influenced by the steric hindrance of the phosphine ligands and/or the substrates. Once N,N-diarylhydrazine is

The application of desymmetric enantioselective reduction of cyclic 1,3-dicarbonyl compounds in the total synthesis of terpenoid and alkaloid natural products

• Dong-Xing Tan and
• Fu-She Han

Beilstein J. Org. Chem. 2025, 21, 2085–2102, doi:10.3762/bjoc.21.164

• ], the enzyme-catalyzed desymmetric enantioselective reduction of 28, afforded hydroxyketone 54 in 65% yield with >99% ee and 8–9:1 dr on multigram scale [34]. Functional group transformations of 54 in four steps produced sterically hindered allyl triflate 55. By employing the palladacycle catalyst 45

Aryl iodane-induced cascade arylation–1,2-silyl shift–heterocyclization of propargylsilanes under copper catalysis

• Rasma Kroņkalne,
• Rūdolfs Beļaunieks,
• Armands Sebris,
• Anatoly Mishnev and
• Māris Turks

Beilstein J. Org. Chem. 2025, 21, 1984–1994, doi:10.3762/bjoc.21.154

• stabilized allyl cation intermediates that undergo regioselective trapping by internal O- and N-nucleophiles furnishing functionalized heterocycles. This method provides access to tetrahydrofuran or pyrrolidine frameworks, each bearing a trifunctionalized (E)-configured vinyl side chain. The use of a shorter

• on intermediate allyl cation (Scheme 1C). The obtained tetrahydrofuran and pyrrolidine derivatives with highly substituted vinyl side-chains are regarded as privileged structures in medical chemistry [23][24]. Moreover, the resulting styryl functionality (Ph-C=C-) is often found in drug molecules as

• can arylate propargylsilanes and induce a 1,2-silyl shift to generate β-Si-stabilized allyl cations. Compared to the previously employed two-step halocyclization–cross-coupling sequence [22], this approach offers a shorter, [Pd]-free synthetic sequence to the modified styryl-containing tetrahydrofuran

Asymmetric total synthesis of tricyclic prostaglandin D2 metabolite methyl ester via oxidative radical cyclization

• Miao Xiao,
• Liuyang Pu,
• Qiaoli Shang,
• Lei Zhu and
• Jun Huang

Beilstein J. Org. Chem. 2025, 21, 1964–1972, doi:10.3762/bjoc.21.152

• nitrate (CAN) [29][30] and Fe(ClO4)3·9H2O [31], failed to afford desired product 14 (Table 1, entries 6 and 7). To explore the synthesis of fully functionalized tricyclic core scaffold 12, methods for incorporating the side chain at C14 and for the stereocontrolled introduction of the allyl moiety at C8

• an inseparable mixture of diastereomers at C-15 in a ratio of 1.0/1.1 (1H NMR analysis). Having established a route to the bicyclic hemiketal 21, we investigated the stereoselective introduction of an allyl moiety at C8 for the synthesis of compound 25 according to the strategy in Scheme 3. Treatment

• of 21 with allyl alcohol and triphenylphosphine afforded transesterification product 22 in 21% yield [33], accompanied by unidentified decarboxylation by-products. A variety of standard conditions failed to promote the palladium-catalyzed decarboxylative allylation of allylic β-ketocarboxylate

3,3'-Linked BINOL macrocycles: optimized synthesis of crown ethers featuring one or two BINOL units

• Somayyeh Kheirjou,
• Jan Riebe,
• Maike Thiele,
• Christoph Wölper and
• Jochen Niemeyer

Beilstein J. Org. Chem. 2025, 21, 1719–1729, doi:10.3762/bjoc.21.134

• synthesis of the allyl tosyl ethylene glycol (see Figure 1e) can be avoided and the bistosylated ethylene glycol 8 (available in one step) can be used instead. Secondly, the ring-closing metathesis was substituted for an operationally simple Williamson reaction. This results in macrocycles with regular

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

• traceless hydrolysis of β-GlcN-derived allyl glycosides with retention of the anomeric configuration [102]. Anomeric deallylation was achieved through an initial double-bond isomerization to the propenyl moiety, followed by oxidation of the glycosidic prop-1-enyl group to a formyl group, as in 111, with

Azide–alkyne cycloaddition (click) reaction in biomass-derived solvent Cyrene^TM under one-pot conditions

• Zoltán Medgyesi and
• László T. Mika

Beilstein J. Org. Chem. 2025, 21, 1544–1551, doi:10.3762/bjoc.21.117

• -phenyl-1H-1,2,3- and 1-allyl-4-substituted-1H-1,2,3-triazoles were synthesized under one-pot conditions and isolated with good to excellent yields (50–96%) and purity (>98%). The observed results represent an example that proves that biomass-derived safer solvents can be introduced into a synthetically

• –carbon double bond in a certain molecular structure could allow for efficient subsequent functionalization via, for example, an addition reaction, opening possibilities for building even more complex molecular skeletons involving 1,2,3-triazole units. Using allyl bromide in the reaction sequence results

• in the formation of 1-allyl-4-substituted-1H-1,2,3-triazoles bearing a terminal C–C double bond moiety. Thus, we attempted to prepare a series of 1-allyl-4-substituted-1H-1,2,3-triazoles (Figure 5, 6a–f) from allyl bromide (4g) and selected acetylenes 2a–f. Similar to the formation of N-substituted-4

Microwave-enhanced additive-free C–H amination of benzoxazoles catalysed by supported copper

• Andrei Paraschiv,
• Valentina Maruzzo,
• Filippo Pettazzi,
• Stefano Magliocco,
• Paolo Inaudi,
• Daria Brambilla,
• Gloria Berlier,
• Giancarlo Cravotto and
• Katia Martina

Beilstein J. Org. Chem. 2025, 21, 1462–1476, doi:10.3762/bjoc.21.108

• products 2o, 2r and 2s in the range of 61–87%. The protocol demonstrated compatibility with more lipophilic amines, such as 1n, and also tolerated amine 1q containing an allyl substituent. When the reaction was carried out using substituted benzoxazoles (see Scheme 4), their reactivity with piperidine was

Oxetanes: formation, reactivity and total syntheses of natural products

• Peter Gabko,
• Martin Kalník and
• Maroš Bella

Beilstein J. Org. Chem. 2025, 21, 1324–1373, doi:10.3762/bjoc.21.101

• , vinyl, ethynyl or sulphide are sufficient if a superbase such as LIDAKOR or LICKOR is used (Scheme 16) [54][55]. The reaction tends to be remarkably regioselective (in terms of the epoxide opening) and stereoselective, however, it should be treated with caution in case of allyl ethers as they can also

• polysubstituted oxetanes 64 (Scheme 18) [57]. The mechanism is based on a 1,5-HAT/radical recombination sequence where the H-atom transfer is triggered by an S0 → T1 excitation of the starting allyl ether 63 using an iridium photosensitiser and blue light for irradiation. The method employs mild reaction

Recent advances in oxidative radical difunctionalization of N-arylacrylamides enabled by carbon radical reagents

• Jiangfei Chen,
• Yi-Lin Qu,
• Ming Yuan,
• Xiang-Mei Wu,
• Heng-Pei Jiang,
• Ying Fu and
• Shengrong Guo

Beilstein J. Org. Chem. 2025, 21, 1207–1271, doi:10.3762/bjoc.21.98

• agents, indicating the feasibility of the protocol (81d,e). The method was further extended to substrates bearing functional groups, such as esters, nitriles, and silanes, all of which were well-tolerated under the optimized conditions (81f–i). Expanding the substrates to include N-allyl-N

• , α-bromo ketones, and α-bromo nitriles, effectively participated in the reaction (88f–i). Even a more sterically hindered substrate also underwent successful cyclization affording 88j, thus further underscoring the robustness of this transformation. However, attempts using benzyl bromide, allyl

Synthetic approach to borrelidin fragments: focus on key intermediates

• Yudhi Dwi Kurniawan,
• Zetryana Puteri Tachrim,
• Teni Ernawati,
• Faris Hermawan,
• Ima Nurasiyah and
• Muhammad Alfin Sulmantara

Beilstein J. Org. Chem. 2025, 21, 1135–1160, doi:10.3762/bjoc.21.91

• DIBAL-H to aldehyde 110 also resulted in stereochemical inversion (85%, anti/syn >15:1). Subsequent chelation-controlled allylation of aldehyde 110, following Ōmura’s method [27][29], employed allyltrimethylsilane and MgBr2·OEt2, yielding allyl alcohol 111 in 86% yield with exclusive

• in their laboratory. The strategy primarily involved the reaction of a chiral organometallic reagent 115 with a chiral allyl electrophile 114, as depicted in Scheme 18. The resulting deoxypropionate 113 was obtained with the newly formed stereocenter controlled by the reagent directing group (RDG

• ) attached to the allyl precursor 114. Iteration of this process required ozonolysis of 113, followed by its conversion to an organometallic intermediate 116, which was then reacted with allyl 114 to yield another deoxypropionate product, 117. The synthesis began with the preparation of the precursor chiral