Novel macrocycles: from synthesis to supramolecular function

• Veronica Iuliano,
• Carmen Talotta,
• Margherita De Rosa,
• Paolo Della Sala,
• Konrad Tiefenbacher,
• Pablo Ballester and
• Carmine Gaeta

Beilstein J. Org. Chem. 2026, 22, 982–985, doi:10.3762/bjoc.22.76

• functional soft materials. Asymmetric frameworks are also central to the research reported by Niemeyer and co-workers [36], who focused on the synthesis of crown ethers bearing one or two BINOL units. Their paper outlines highly practical synthetic routes to open a diverse library of chiral architectures

Electrochemical reduction of unsaturated carbon–carbon bonds via 3d transition-metal catalysis

• Geon Kang,
• Minki Jeon,
• Pooja Kumari Jat,
• Cheoljae Kim and
• Isaac Choi

Beilstein J. Org. Chem. 2026, 22, 955–981, doi:10.3762/bjoc.22.75

• the cobalt mediator can be productively integrated with a chiral nickel cocatalyst and structurally varied substrates to enable efficient, stereocontrolled hydrogenation under comparatively mild, fixed-potential conditions. Mechanistic studies using deuterium-labeled substrates further indicated that

Recent advances in copper-catalyzed direct hydroamination of alkenes with (hetero)aromatic amines

• Hyejeong Lee and
• Yunmi Lee

Beilstein J. Org. Chem. 2026, 22, 925–947, doi:10.3762/bjoc.22.73

• authors also explored an asymmetric version of this reaction using chiral bisoxazoline–Cu(II) complexes. Coordination of ethenetricarboxylate substrate 16 to the chiral Lewis acid created a chiral environment that controlled the facial selectivity of the nucleophilic attack. The conjugate addition of N

• transformation, the chiral Pybox-diPh/Cu(OTf)2·C6H6 complex initially promoted imine formation followed by asymmetric alkynylation, generating the α,β-unsaturated ester intermediate 23. Subsequent treatment with LiHMDS (lithium bis(trimethylsilyl)amide) induced base-promoted intramolecular aza-Michael

• catalyst, affording chiral cyclopropyl pyrazoles with high levels of regio-, diastereo-, and enantioselectivities (Scheme 15) [55]. In the presence of Cu(CH3CN)4PF6 (5 mol %) and the chiral bisphosphine ligand (R,R)-iPr-DuPhos, the coupling of pyrazoles with substituted cyclopropenes proceeded efficiently

Chiral cyclopropenimine-catalyzed enantioselective Michael reactions of phenol and benzofuran-derived α,β-unsaturated pyrazolamides with benzophenone-imine of glycine esters

• Ya Bai,
• Xue-Ying Wang,
• Si-Kai Zhu,
• Yan-Ting Shen,
• Sheng-Yong Zhang and
• Ping-An Wang

Beilstein J. Org. Chem. 2026, 22, 888–896, doi:10.3762/bjoc.22.69

• , 710032, China School of Pharmacy, Lanzhou University, Lanzhou, 730000, China 10.3762/bjoc.22.69 Abstract The enantioselective Michael reactions of benzophenone-imine of glycine esters with phenol- and benzofuran-derived α,β-unsaturated pyrazolamides have been realized by using a chiral cyclopropenimine

• adjacent stereocenters, which was obtained from in-situ acidic hydrolysis and lactamization of the corresponding Michael product. Keywords: α,β-unsaturated pyrazolamide; chiral cyclopropenimine; glutamic acid; lactamization; Michael addition; Introduction Phenols and benzofurans are feedstock chemicals

• series of 3-substitued glutamic acid esters in high yields and diastereoselectivities through DBU-catalyzed Michael additions of benzophenone-imine of glycine ester and α,β-unsaturated esters which derived from phenols and benzofurans under mild conditions [5][6]. The chiral 3-aryl-substituted glutamic

Unsymmetrical sulfoxides with sterically hindered catechol fragment: synthesis, structure, electrochemical properties, and antiradical activity

• Daria A. Burmistrova,
• Vasiliy A. Fokin,
• Oleg P. Demidov,
• Mikhail A. Kiskin,
• Maxim V. Arsenyev,
• Andrey I. Poddel’sky,
• Nadezhda T. Berberova and
• Ivan V. Smolyaninov

Beilstein J. Org. Chem. 2026, 22, 828–837, doi:10.3762/bjoc.22.65

• component of Oxone®) [37] – are commonly employed for this purpose. One of the most accessible approaches uses hydrogen peroxide along with catalytic systems based on transition metals [38]. Notably, this process is not stereoselective and affords chiral sulfoxides as a mixture of enantiomers. Besides

Rongalite addition to dienones: diastereoselectivity in cyclic sulfone synthesis; stereochemical rationalization and prospects as a general conjugate nucleophile

• Melina Goga,
• Hao Zong,
• James Franco,
• Jazmine Prana,
• Rudolph Michel,
• Antonia Muro,
• Elana Rubin,
• Janet Brenya,
• Henk Eshuis and
• Magnus W. P. Bebbington

Beilstein J. Org. Chem. 2026, 22, 742–752, doi:10.3762/bjoc.22.56

• (chiral) diastereomer of the products 3 and 4 in each case – reaction of the nucleophile with either face of the iminium ion or ketone gives the same diastereomer, as illustrated. By contrast, hydride reduction of 1b gave an approx. 9:1 mixture of products 5 and 6, as judged by the crude 1H NMR spectrum

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

• derivatives with multiple chiral centers under high regio- and stereocontrol. Currently, strategies using azomethine ylides based on imino esters or α-amino acids with a variety of cyclic and acyclic carbonyl compounds dominate. Enantioselective (3 + 2) cycloaddition reactions of azomethine ylides obtained

• from imino esters, catalyzed by chiral Cu(I,II) and Ag(I) complexes, are widely used. Reactions using α-amino acids proceed, in most cases, without the use of catalysts, with high yields and high stereoselectivity. Electrophilic alkenes of various structures, (hetero)aromatic olefins and benzofulvenes

• with a dipolarophile, such as an alkene or alkyne, to form a five-membered heterocycle in one step. Currently, this type of reaction allows for the efficient preparation of bi- and polycyclic fused or spiro-linked structures with multiple chiral centers and high regio- and stereocontrol [1][2][3][4

Synthesis of depressin, cryptomeridiol and 4-epi-cryptomeridiol enabled by a terpenoid chiral pool-producing platform

• Yao Kong,
• Tao Wang,
• Chen Wang,
• Pengcheng Zhang,
• Yuanning Liu,
• Kaibiao Wang,
• Fen Liu,
• Hongli Jia and
• Zhengren Xu

Beilstein J. Org. Chem. 2026, 22, 683–690, doi:10.3762/bjoc.22.53

• of different plants with broad biological activity. Most of the syntheses focused on the transformation of chiral pool substrates into their trans-6/6-fused ring system. We herein report the synthesis of compounds 1–3 by taking advantage of an expanded chiral pool strategy, in which the terpenoid

• hydroxy group allowed the synthesis of compound 1 from 4 in nine steps. Selective acid-mediated 5,10-transannular cyclization of 5 followed by hydration reaction furnished both products 2 and 3 in two steps. Keywords: chemoenzymatic synthesis; chiral pool; isopentenol utilization pathway; terpene

• also provided us with several abundant chiral building blocks which are normally referred to as the ‘chiral pool’ to start with [4][5]. Representative terpenoid products, such as (−)-carvone, (+)-3-carene, and (+)-sclareolide that are typically isolated from renewable resources (Figure 1a), continue to

Kinetic resolution of racemic planar-chiral vinylcymantrenes by molybdenum-catalyzed asymmetric metathesis dimerization

• Haruna Imazu,
• Hitoshi Izu,
• Yasuhiro Ohki and
• Masamichi Ogasawara

Beilstein J. Org. Chem. 2026, 22, 568–574, doi:10.3762/bjoc.22.42

• Science Institute, Tokushima University, Tokushima 770-8501, Japan 10.3762/bjoc.22.42 Abstract Highly diastereo- and enantioselective kinetic resolution (KR) of a series of racemic planar-chiral 1-R-2-vinylcymantrenes (rac-1; R = Br, Me, I) was realized by an asymmetric metathesis dimerization (AMD

• ) reaction catalyzed by a chiral molybdenum-alkylidene precatalyst. The Mo/(R)-L1 precatalyst promoted the AMD/KR reaction of rac-1a (R = Br) to give (E)-(R,R)-2a of 99% ee together with unreacted recovered (S)-1a of 45% ee at 37% conversion. The diastereoselectivity of this reaction was excellent with

• chiral-2a/meso-2a = 96:4 molar ratio, and the selectivity factor (krel) was calculated to be 754 based on a second-order equation. In all the three substrates examined, the dimerized products, chiral-2, were obtained in >98% ee thanks to the outstanding enantioselectivity. Keywords: cymantrene; kinetic

Experimental and DFT studies on the regioselective methanolysis of 5-azido-9-oxabicyclo[6.1.0]nonan-4-yl 4-nitrobenzoate isomers

• İlknur Polat,
• Selçuk Eşsiz and
• Emine Salamci

Beilstein J. Org. Chem. 2026, 22, 547–556, doi:10.3762/bjoc.22.40

• , pharmaceutical compounds, and chiral ligands. The Lewis acid-catalyzed ring-opening reaction of cyclohexene oxide by MeZH (Z = O, S, and NH) is well known [20]. However, studies on large-sized bicyclic epoxides remain relatively limited in the published literature. In our previous study, we performed the ring

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

• , Nicolaou and co-workers merged both building blocks within a Ni(II)/Cr(II)-catalyzed NHK reaction using chiral ligand 206 (Scheme 23) [95]. Upon treatment with DBU, 3-methylenetetrahydrofuran 201 was obtained in 56% yield over two steps. PMB-deprotection, iodination and selective reduction of the ester

Recent advances in the stereoselective synthesis of distal biaxially chiral molecules

• Fanxing Zhou,
• Chen Zhang,
• Lingyu Sun,
• Yiyun Fang,
• Siming Zheng,
• Lina Hu,
• Mengyang Shen,
• Zhen Zhao,
• Wei Xu,
• Yunqiang Sun and
• Zi-Qiang Rong

Beilstein J. Org. Chem. 2026, 22, 461–479, doi:10.3762/bjoc.22.34

• distal axial chiralities are widely applied in chiral ligands, natural products, and anticancer agents, with their unique spatial configurations endowing them with distinctive functions and values. Although significant progress has been made in the asymmetric synthesis of distal biaxial chirality

• biaxial chirality, multistep sequential generation, and conversion from central to biaxial chirality, with the aim of providing new perspectives and methodologies for further development in this area. Keywords: axially chiral compounds; stereoselective synthesis; Introduction In recent years, axially

• chiral scaffolds, which arise from hindered rotation between two planes connected by a single bond, have attracted increasing attention due to their widespread applications in chiral ligands, organocatalysts [1], and functional materials [2], making them highly valuable molecular frameworks in organic

A facile and practical method for the synthesis of trans-(±)-taxifolin and its derivatives via Darzens reaction

• Bo Peng,
• Panpan Yang,
• Maaz Khan,
• Xiaotong Lin,
• Jiang Wu,
• Peng Fu and
• Qingqing Wu

Beilstein J. Org. Chem. 2026, 22, 443–450, doi:10.3762/bjoc.22.31

• Pharmacy, Shenzhen Technology University, Shenzhen 518118, China 10.3762/bjoc.22.31 Abstract The synthesis of racemic trans-taxifolin (trans-(±)-taxifolin) and its derivatives and subsequent chiral separation is the most prevalent chemical method to obtain enantiomerically pure taxifolin and its

• transformation from dietary food to multifunctional medications in the near future. Taxifolin is a chiral compound with two stereocenters and exists as trans or cis isomers. It is commonly referred to as the trans dextral form (trans-(+)-taxifolin), which has higher bioactivity than its levorotatory enantiomer

• produce taxifolin but also faces the problems of scale-up and high cost. As a result, the development of a practical synthetic approach is of importance and significance. A chiral synthesis for taxifolin was reported by the use of (+)-catechin as the starting material [15][16], but (+)-catechin is not

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

• Advanced Science and Technology, Kumamoto University, Kurokami, Kumamoto 865-8555, Japan 10.3762/bjoc.22.30 Abstract Planar chiral C6-substituted oxa[7]orthocyclophenes were designed and synthesized, and their stereochemical behavior was analyzed. The Kumada–Tamao coupling of the C6-iodo-substituted

• successfully transformed into central chirality by epoxidation without loss of enantiomeric purity. Keywords: dynamic chirality; medium-sized heterocycle; orthocyclophene; planar chirality; stereochemical analysis; Introduction In the course of our study on planar chiral medium-sized cyclic molecules [1][2

• ideal alkene plane. Stereochemical analysis of C6-substituted oxacyclophenes Next, HPLC analyses using a chiral stationary phase (chiral column) of the C6-substituted oxacyclophenes were conducted. The baseline separations of the enantiomers of 1ab and 1ad were achieved by using CHIRALCEL OJ-H as the

Cone p-aminocalix[4]arenes enriched with ‘clickable’ alkyne or azide functionalities

• Ilia Korniltsev,
• Vasily Bazhenov,
• Alexander Gorbunov,
• Dmitry Cheshkov,
• Stanislav Bezzubov,
• Vladimir Kovalev and
• Ivan Vatsouro

Beilstein J. Org. Chem. 2026, 22, 399–415, doi:10.3762/bjoc.22.28

• corresponded to chiral C2-symmetric homodimeric capsules in both cases. The 1H NMR spectrum of the equimolar mixture 48/52 (taken as an example) contained one set of signals from the C2-symmetric heterodimer 48·CDCl3·52, but not from the homodimers 48·CDCl3·48 and 52·CDCl3·52, and thus reflected the expected

Electrosynthetic access to unsymmetrical oxaza[8]helicenes with high chiral stability and strong circularly polarized luminescence (CPL)

• Tin Zar Aye,
• Rubal Sharma,
• Muthu Karuppasamy,
• Daiya Suzuki,
• Haruka Nakajima,
• Yoshitane Imai,
• Mitsuhiro Arisawa,
• Mohamed S. H. Salem and
• Shinobu Takizawa

Beilstein J. Org. Chem. 2026, 22, 372–382, doi:10.3762/bjoc.22.25

• Heterohelicenes are compelling chiral π-conjugated scaffolds for optoelectronic and chiral-photonic technologies because their helical frameworks and doped heteroatoms endow them with various photophysical, chiroptical, and electronic merits. However, unsymmetrical heterohelicenes remain rare, as their synthesis

• ) relative to their oxaza[7]helicene analogues (<25 kcal/mol). After chiral HPLC separation, the enantiomers display mirror-image CD and strong solution CPL, with |glum| up to 2.6 × 10−3 and fluorescence brightness up to 30.75 M−1 cm−1. Keywords: chemoselectivity; chiroptical; circular dichroism

• ; electrochemistry; emission; helical elongation; helicene; photophysical; Introduction Chirality is a pervasive feature of natural and artificial systems, and chiral small molecules continue to underpin advances in chemistry and materials science [1][2]. Among them, helicenes – ortho-condensed polycyclic aromatic

Non-central chirality in organic chemistry

• Ken Tanaka and
• Naohiko Yoshikai

Beilstein J. Org. Chem. 2026, 22, 370–371, doi:10.3762/bjoc.22.24

• axial, planar, or helical chirality individually, often organized along specific molecular classes or application-driven themes such as asymmetric catalysis or chiral materials. In contrast, this Thematic Issue deliberately brings together diverse manifestations of non-central chirality under a single

• complementary roles played by non-central chiral molecules in contemporary organic chemistry. First, they continue to serve as demanding benchmarks for asymmetric synthesis, probing how far stereochemical information can be transmitted and controlled when the stereogenic element is spatially or conceptually

• remote from the reaction site. Second, non-central chiral frameworks remain fertile ground for catalyst design, not only as derivatives of established motifs but also as newly conceived architectures that redefine how chirality can be embedded into catalytic systems. Third, the pronounced chiroptical and

Recent advances in the cleavage of non-activated amides

• Eun-Sol Choi and
• Hyo-Jun Lee

Beilstein J. Org. Chem. 2026, 22, 352–369, doi:10.3762/bjoc.22.23

• undergoes hydrolysis to afford the benzyl ester 30. Under the optimized conditions, primary, secondary, and tertiary amides 12, 31–33 were successfully converted to benzyl esters in high yields. Notably, loss of enantiopurity of chiral amide 33 was not observed during esterification. Sulfuryl fluoride

• electrophilic activation of pyrrolidine-derived amides with Tf2O and 2-bromopyridine generates a keteniminium ion O, which undergoes nucleophilic addition to form an enamine intermediate P. Subsequent electrophilic α-fluorination followed by hydrolysis produces the α-fluoroester products. Notably, the C2-chiral

• amide 44, incorporating (2S,5S)-2,5-diphenylpyrrolidine as a chiral auxiliary, furnished the enantioenriched ester 45* in 64% yield with 90% ee. Wan et al. investigated the chlorination of primary amides using trichloroisocyanuric acid (TCCA) to promote esterification (Scheme 10) [58]. In the presence

Ring contraction and ring expansion reactions in terpenoid biosynthesis and their application to total synthesis

• Nicolas Kratena,
• Nicolas Heinzig and
• Peter Gärtner

Beilstein J. Org. Chem. 2026, 22, 289–343, doi:10.3762/bjoc.22.21

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

• aromatic ligand is necessary to set the absolute stereochemistry of the organic product. This relative stereochemistry depends on which face of the arene is coordinated and can be governed by high chiral recognition for binding (coordination diastereomer ratio, cdr) or stereoelectronic differentiation

• manifolds) and unlocking enantioselective variants to access three-dimensional, chiral architectures. In contrast, η2- and η4-coordination modes have been explored extensively from a structural and stoichiometric reactivity standpoint, yet catalytic manifestations remain conspicuously rare. The energetic

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

• [22] and as insecticides [23]. Particularly, phosphate diesters are among the most important synthetic catalysts, such as the Akiyama–Terada catalyst that serves as a chiral Brønsted acid catalyst [24][25] and promotes a variety of stereoselective reactions. Phosphate diesters also catalyze the ring

Screwing the helical chirality through terminal peri-functionalization

• Devesh Chandra,
• Sachin and
• Upendra Sharma

Beilstein J. Org. Chem. 2026, 22, 205–212, doi:10.3762/bjoc.22.14

• of chirality. Molecules with helical chirality impart a crucial role in several biological phenomena as well as in modern materials applications. Classically, the generation of chiral helicity in organic molecules relies on a ring extension by means of cycloaddition and related reactions. Recently

• , the peri-functionalization approach paved a new pathway for the generation of chiral helical molecules. In this article, we highlight the key advancements in these parallel approaches for the generation of helical chiral architectures. Keywords: catalysis; C–H functionalization; helical chirality

• another important type of chirality, where the chirality is controlled by restricted rotation among an axis. These types of molecules play an important role as chiral ligands in organic synthesis, i.e., BINOL, BINAP, etc. [9][10][11]. Another form of chirality, where chirality depends on a constrained

Streptoquinolines A and B, new antibacterial meroterpenoids produced by Streptomyces sp. TMPU-A0679

• Akiho Yagi,
• Hitomi Tomura,
• Ami Konno and
• Ryuji Uchida

Beilstein J. Org. Chem. 2026, 22, 185–191, doi:10.3762/bjoc.22.12

• 1H,1H COSY and HMBC correlations as those observed for 1 (Figure 2), confirming that compound 2 shared the same planar structure. The specific rotations of 1 and 2 were similar in both sign and magnitude, suggesting that they shared the same absolute configuration for most chiral centers. However, a

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

• RU58841. Moreover, chiral alcohols such as ʟ-menthol are well tolerated, affording diastereomeric sulfinimidate esters that can undergo stereospecific Grignard substitutions to furnish enantioenriched sulfilimines with up to 93% ee. These results demonstrate the potential of sulfinimidate esters as

• PIDA-mediated oxidative esterification of sulfenamides, rely on stoichiometric hypervalent iodine reagents and have not demonstrated broadly efficient reactivity with sterically demanding or chiral alcohols such as ʟ-menthol, where only modest conversion was observed in our hands. Motivated by these

• , we anticipated that an NBS/NaHCO3-based protocol would provide a more practical and chiral-alcohol-compatible alternative to our previous PIDA system. A conceptual comparison between our previous PIDA-mediated protocol and the present NBS/NaHCO3-mediated protocol is summarized in Scheme 1. However

Asymmetric Mannich reaction of aromatic imines with malonates in the presence of multifunctional catalysts

• Kadri Kriis,
• Harry Martõnov,
• Annette Miller,
• Mia Peterson,
• Ivar Järving and
• Tõnis Kanger

Beilstein J. Org. Chem. 2026, 22, 151–157, doi:10.3762/bjoc.22.8

• compounds, and catalyst J as a trifluoroacetylated chiral tertiary amine, which lacks iodine. The reaction of imine 1 with dimethyl malonate was selected for the investigation as a model reaction. Based on our previous experience the catalyst screening was carried out in toluene in the presence of 10 mol

• ]. Although basic conditions caused partial racemization during the protection or deprotection step, the Boc-protected amine was obtained in low enantiomeric purity. Chiral HPLC analysis and comparison with an authentic sample revealed the S-configuration of the Mannich adduct [29]. Absolute configurations of

• . Although the activation mechanism was not proved unambiguously, it is assumed that steric effects of the chiral fragment together with a network of noncovalent interactions, including halogen and hydrogen bonds, are responsible for the high enantioselectivity of the reaction. Further developments of the