CO₂ complexation with cyclodextrins

• Cecilie Høgfeldt Jessen,
• Jesper Bendix,
• Theis Brock Nannestad,
• Heloisa Bordallo,
• Martin Jæger Pedersen,
• Christian Marcus Pedersen and
• Mikael Bols

Beilstein J. Org. Chem. 2023, 19, 1021–1027, doi:10.3762/bjoc.19.78

• from industrial processes, power generation, and transportation contribute significantly to global warming and climate change. Carbon capture and storage (CCS) technologies are essential to reduce these emissions and mitigate the effects of climate change. Cyclodextrins (CDs), cyclic oligosaccharides

Copper-catalyzed N-arylation of amines with aryliodonium ylides in water

• Kasturi U. Nabar,
• Bhalchandra M. Bhanage and
• Sudam G. Dawande

Beilstein J. Org. Chem. 2023, 19, 1008–1014, doi:10.3762/bjoc.19.76

• ) as a product with 59% yield. Similarly, the reaction of cyclic secondary amines also resulted in arylation under the optimal reaction conditions to give products 3s–v with 42–48% yields. The treatment of indoline with iodonium ylide 2b in the presence of 10 mol % of CuSO4·5H2O affords product 3w in

The unique reactivity of 5,6-unsubstituted 1,4-dihydropyridine in the Huisgen 1,4-diploar cycloaddition and formal [2 + 2] cycloaddition

• Xiu-Yu Chen,
• Hui Zheng,
• Ying Han,
• Jing Sun and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2023, 19, 982–990, doi:10.3762/bjoc.19.73

• -configured. For explaining the formation of the various cyclic compounds, a plausible reaction mechanism was proposed on the base of the previously reported works [41][42][43][44] and the present experiments (Scheme 2). Initially, the nucleophilic addition of isoquinoline to dimethyl acetylenedicarboxylate

Aromatic C–H bond functionalization through organocatalyzed asymmetric intermolecular aza-Friedel–Crafts reaction: a recent update

• Anup Biswas

Beilstein J. Org. Chem. 2023, 19, 956–981, doi:10.3762/bjoc.19.72

• aza-Friedel–Crafts process between indoles 4 and cyclic N-sulfonyl ketimines 5. The authors employed the BINOL-based chiral phosphoric acid P2 bearing two imidazoline moieties at the ortho-positions as the catalyst which activates both reactants through H-bonding where the NH group of the nucleophile

• than with indoles (Scheme 3) [26]. In 2018, Kim and co-workers developed an aza-Friedel–Crafts protocol involving pyrroles 9 as the π-nucleophile in combination with cyclic N-sulfimines 12. The chiral phosphoric acid P4 was used to catalyze the introduction of a pyrrole-substituted aza-quaternary

• stereocenter in cyclic sulfamidate derivatives. N-Alkyl and N-benzyl-substituted pyrroles responded to the process with appreciable enantioefficiency. However, pyrrole was not proved to be the efficient substrate in terms of stereocontrol [27] (Scheme 4a). In the very next year, pyrrole was successfully

Intermediates and shunt products of massiliachelin biosynthesis in Massilia sp. NR 4-1

• Till Steinmetz,
• Blaise Kimbadi Lombe and
• Markus Nett

Beilstein J. Org. Chem. 2023, 19, 909–917, doi:10.3762/bjoc.19.69

• ], the cyclic guanidine alkaloid massinidine [17], and the siderophore massiliachelin [18]. An antiSMASH analysis [19] of the genome of Massilia sp. NR 4-1 revealed the presence of additional biosynthetic gene clusters, including another putative metallophore gene cluster (ACZ75_RS05545–ACZ75_RS06020

Synthesis of aliphatic nitriles from cyclobutanone oxime mediated by sulfuryl fluoride (SO₂F₂)

• Xian-Lin Chen and
• Hua-Li Qin

Beilstein J. Org. Chem. 2023, 19, 901–908, doi:10.3762/bjoc.19.68

• ], Liu [35], and Yang [36] achieved similar transformations through visible-light photocatalysis. In addition, Guo [37][38] improved the protocol by using low-cost nickel and iron catalysts. However, most of these advancements mainly relied on the excellent redox potential manipulation of cyclic oxime

First synthesis of acylated nitrocyclopropanes

• Kento Iwai,
• Rikiya Kamidate,
• Khimiya Wada,
• Haruyasu Asahara and
• Nagatoshi Nishiwaki

Beilstein J. Org. Chem. 2023, 19, 892–900, doi:10.3762/bjoc.19.67

• 3b used in only three cases [12][13][19], to the best of our knowledge. Extending beyond Scheme 2, only two syntheses of nitrocyclopropanes containing cyclic keto esters or diketones have been reported [20][21]. These findings indicate that the synthesis of nitrocyclopropanes with an acyl group is

• occurs, leading to five-membered cyclic nitronates [23]. To the contrary, such reaction was not observed at all, which is presumably due to the lower electron-donating ability of the benzene ring. The other adducts 4c–g were subjected to the cyclization under the same conditions (Table 3). When the

• acyl group are unknown, except for a derivative of cyclic diketone [20][21]. Although diacetyl derivative 13 has been reported in some studies [12][13][19], we corrected its structure to dihydrofuran 8. This is the first report of the synthesis of acylated nitrocyclopropanes 1. After the conjugate

Asymmetric tandem conjugate addition and reaction with carbocations on acylimidazole Michael acceptors

• Brigita Mudráková,
• Renata Marcia de Figueiredo,
• Jean-Marc Campagne and
• Radovan Šebesta

Beilstein J. Org. Chem. 2023, 19, 881–888, doi:10.3762/bjoc.19.65

• earlier experience, we employed the tropylium ion with the more lipophilic bis(trifluoromethane)sulfinimide (NTf2) anion because of its better solubility in the applied organic solvents than the commercially available tetrafluoroborate (BF4) form [22][23][24]. The cyclic urea DMEU (1,3-dimethyl-2

Light-responsive rotaxane-based materials: inducing motion in the solid state

• Adrian Saura-Sanmartin

Beilstein J. Org. Chem. 2023, 19, 873–880, doi:10.3762/bjoc.19.64

• Photoresponsive rotaxane discrete crystals A complete understanding of the crystallization mechanisms accompanied by a rational design can lead to the obtention of crystalline molecular materials which allow the dynamics of the counterparts to take place [35][36][37]. Indeed, the motion of the cyclic counterparts

• pseudorotaxanes, the supramolecular interactions between the counterparts are retained, thus constituting stable intertwined species showing analogous properties to those of rotaxanes. The pseudorotaxanes 1 were constituted by a dibenzo-24-crown-8 cyclic component and an ammonium-based thread functionalized with

• UMUMOF-(E)-3 due to the decrease of the number of hydrogen bonds interactions between the counterparts, as determined by solid-state 2H NMR. Interestingly, UMUMOF-(E)-3 was employed as a molecular nanodispenser of para-benzoquinone working through a cyclic operation mode which involved three steps

Pyridine C(sp²)–H bond functionalization under transition-metal and rare earth metal catalysis

• Haritha Sindhe,
• Malladi Mounika Reddy,
• Karthikeyan Rajkumar,
• Akshay Kamble,
• Amardeep Singh,
• Anand Kumar and
• Satyasheel Sharma

Beilstein J. Org. Chem. 2023, 19, 820–863, doi:10.3762/bjoc.19.62

• starting from both cyclic and acyclic alkyl bromides. The findings of the reaction’s stereochemistry and observations made during some cyclization or ring-opening reactions indicated that the C–H alkylation may proceed through a radical-type mechanism. Next, in 2013, Wang and co-workers [52] reported a

• . Subsequently, insertion of alkene 68 provides the cyclic Pd(II) intermediate 72 which undergoes β-hydride elimination to produce the desired product 69. In the same year, Ramana and Goriya [75] proposed an unexpected C-6 (C-2)-propenylation reaction of pyridine in the presence of allyl bromide (73) and a Ru

• results in the five-membered rhodacycle 184 which is followed by a second regioselective insertion of alkyne 179 into the Rh–C bond of 184 providing the seven-membered cyclic intermediate 185. Further reductive elimination furnishes the quinoline product 180 and a Rh(I) species, with the latter being

Eschenmoser coupling reactions starting from primary thioamides. When do they work and when not?

• Lukáš Marek,
• Jiří Váňa,
• Jan Svoboda and
• Jiří Hanusek

Beilstein J. Org. Chem. 2023, 19, 808–819, doi:10.3762/bjoc.19.61

• behavior was observed with substrate 4b, where a mixture of thiazole 13, sulfide 14b and thiobenzamide was formed in DMF (Table 3, entries 9 and 10) even without any base. This behavior corresponds to a much worse leaving ability of methylamine (pKa = 10.6) from cyclic intermediate en route to thiazole 13

• acidifying effect as compared to C(CH3)2) and the effect of ring strain [35][36] (C–H in the 5-membered α-thioiminium salt 15 is more acidic than in the 6-membered salts 6a,b or non-cyclic salts 12b). The subsequent formation of the thiirane ring through TS2 (which is strongly entropically favored although

Bromination of endo-7-norbornene derivatives revisited: failure of a computational NMR method in elucidating the configuration of an organic structure

• Demet Demirci Gültekin,
• Arif Daştan,
• Yavuz Taşkesenligil,
• Cavit Kazaz,
• Yunus Zorlu and
• Metin Balci

Beilstein J. Org. Chem. 2023, 19, 764–770, doi:10.3762/bjoc.19.56

• , is certainly not surprising since both electronic and steric factors favor attack on the convex face of the pyramidalized double-bond. Electrophilic bromine can attack the double bond in 1 mainly from exo-face of the double bond to form the cyclic bromonium ions 10. The major products, 2, 3, 4, and 5

Synthesis of medium and large phostams, phostones, and phostines

• Jiaxi Xu

Beilstein J. Org. Chem. 2023, 19, 687–699, doi:10.3762/bjoc.19.50

• bond formation through RCM reaction: Ring-closing metathesis (RCM) is an efficient strategy for the construction of common to large cyclic compounds via the formation of a C=C bond [26], which can be further reduced to a C–C bond. To prepare phostam-derived antitumor agents, ethyl N-allyl-N-(but-3-en-1

• -hexahydro-1,2-oxaphosphecine 2-oxide 26 in 70% yield. After the Pd-catalyzed hydrogenolysis, it was transformed to both cyclic ten-membered phostone 2-(4-methylphenyl)benzothiophene-fused 2-hydroxy-1,2-oxaphosphecane 2-oxide (27) in 40% yield and acyclic (4-(3-methyl-2-(4-methylphenyl)benzo[b]thiophen-4-yl

• –elimination. Both they are potential chiral phosphorus ligands (Scheme 20) [25]. When Fuchs and co-workers investigated the conversion of cyclic vinyl sulfones to vinylphosphonates, they found that the reaction of (1S,2R)-2-methyl-3-(phenylsulfonyl)cyclohept-3-en-1-ol (100) and diethyl phosphonate generated

Synthesis, structure, and properties of switchable cross-conjugated 1,4-diaryl-1,3-butadiynes based on 1,8-bis(dimethylamino)naphthalene

• Semyon V. Tsybulin,
• Ekaterina A. Filatova,
• Alexander F. Pozharskii,
• Valery A. Ozeryanskii and
• Anna V. Gulevskaya

Beilstein J. Org. Chem. 2023, 19, 674–686, doi:10.3762/bjoc.19.49

• -conjugation of 1,8-bis(dimethylamino)naphthalene (DMAN) fragments through a butadiyne linker and a donor–acceptor aryl–C≡C–DMAN conjugation path. The conjugation path can be “switched” simply by protonation of DMAN fragments. X-ray diffraction, UV–vis spectroscopy and cyclic voltammetry are applied to analyze

• us to undertake the current study. X-ray crystallography, UV–vis spectroscopy and cyclic voltammetry were applied to analyze the extent of π-electron conjugation and the efficiency of the particular donor–acceptor conjugation path in chromophores 5. Results and Discussion Synthesis The target

• to its analogs with electron-withdrawing substituents. The redox properties of oligomers 5 were evaluated by cyclic voltammetry (CV) in dichloromethane solution containing 0.1 M n-Bu4NPF6 in the standard three-electrode electrochemical cell: glassy carbon working electrode, platinum auxiliary

Enolates ambushed – asymmetric tandem conjugate addition and subsequent enolate trapping with conventional and less traditional electrophiles

• Péter Kisszékelyi and
• Radovan Šebesta

Beilstein J. Org. Chem. 2023, 19, 593–634, doi:10.3762/bjoc.19.44

• enolate. González-Gómez et al. studied the tandem conjugate addition of dialkylzincs to cyclic enones (9, 12) and the subsequent reaction of the enolate with N-tert-butanesulfinylimines 10 (Scheme 4) [24][25][26]. Their method was applied to a broad range of substrates (5–7-membered rings) with equally

• using acyclic enones 14 [27]. Their tandem conjugate addition/Mannich reaction methodology offers access to various non-cyclic β-aminoketones 16 with multiple contiguous stereocenters in high diastereo- and enantioselectivity (Scheme 5a). Additionally, chiral isoindolinones 18 and 2,3,4-trisubstituted

• imines or their synthetic equivalents. Furthermore, we wanted to develop an enantioselective and diastereoselective process without adding chirality elements within the reagents. For our initial studies, we have selected the well-studied cyclic enones as substrates and the Taniaphos ligand (L14) that has

A new oxidatively stable ligand for the chiral functionalization of amino acids in Ni(II)–Schiff base complexes

• Alena V. Dmitrieva,
• Oleg A. Levitskiy,
• Yuri K. Grishin and
• Tatiana V. Magdesieva

Beilstein J. Org. Chem. 2023, 19, 566–574, doi:10.3762/bjoc.19.41

• employing chiral auxiliaries [4][5] and asymmetric phase-transfer catalysis [6][7]. The former approach is commonly based on the application of chiral derivatives of glycine containing structurally diverse chiral auxiliaries, both cyclic [8][9][10][11] and acyclic [12][13]. Transition-metal complexes

• complexes. Electrochemical properties For further applications of the (GlyNi)L7 and (ΔAlaNi)L7 complexes in electrochemically activated functionalization of amino acid fragments, a more detailed electrochemical study is an important precondition. Electrochemical properties were investigated using cyclic

• cyclic voltammetry time scale. The spin density in the radical anion is mainly localized on the Ni d-orbitals and on the N and O atoms of its coordination environment (see Supporting Information File 1). The reduction of the complex (ΔAlaNi)L7 is irreversible at scan rates lower 2000 mV/s. Full

Transition-metal-catalyzed domino reactions of strained bicyclic alkenes

• Austin Pounder,
• Eric Neufeld,
• Peter Myler and
• William Tam

Beilstein J. Org. Chem. 2023, 19, 487–540, doi:10.3762/bjoc.19.38

• sketched in red, with newly formed cyclic structures being highlighted. Review Earth-abundant metals Among the transition metal used in organic synthesis, the late transition metals like rhodium, palladium, and iridium have taken center stage when it comes to methodology development. Although these late

Computational studies of Brønsted acid-catalyzed transannular cycloadditions of cycloalkenone hydrazones

• Manuel Pedrón,
• Jana Sendra,
• Irene Ginés,
• Tomás Tejero,
• Jose L. Vicario and
• Pedro Merino

Beilstein J. Org. Chem. 2023, 19, 477–486, doi:10.3762/bjoc.19.37

• the outcome of these reactions. The tether(s) connecting the reactive functional groups affects the spatial orientation of the reacting species and introduces strain into the starting cyclic molecule. As a consequence, the reaction barrier is highly dependent on distortion and entropic effects as Houk

Combretastatins D series and analogues: from isolation, synthetic challenges and biological activities

• Jorge de Lima Neto and
• Paulo Henrique Menezes

Beilstein J. Org. Chem. 2023, 19, 399–427, doi:10.3762/bjoc.19.31

• called cyclic diaryl ether heptanoids (DAEH). This review is intended to highlight the structure elucidation, biosynthesis, and biological activity of these compounds as well as the use of different strategies for their synthesis. Keywords: combretastatin D; corniculatolide; isocorniculatolide

• ; macrocycles; Introduction Conceptually, cyclic molecules containing more than 12 covalently connected atoms are called macrocycles and this class comprises several structurally distinct compounds [1]. Due to their structural characteristics and their different biological activities, the isolation of new

• macrocycles and their synthesis finds several examples described in the literature and has already been the subject of review articles [2][3][4]. More recently, cyclic diaryl ether heptanoids (DAEH) [5], another class of macrocycles has been attracting attention not only because of their structural and

Synthesis and reactivity of azole-based iodazinium salts

• Thomas J. Kuczmera,
• Annalena Dietz,
• Andreas Boelke and
• Boris J. Nachtsheim

Beilstein J. Org. Chem. 2023, 19, 317–324, doi:10.3762/bjoc.19.27

• protocol that allowed us to synthesize these novel cyclic iodonium salts in their mono- and dicationic forms, we gained in-depth structural information through single-crystal analysis and demonstrated the ring opening of the heterocycle-bridged iodonium species. For an exclusive set of dicationic

• aryl donors [11][12][13][14][15][16]. Their cyclic derivatives have a proven utility as precursors for the synthesis of hetero- and carbocycles [17][18][19][20][21], and their pronounced σ-holes [22] render them efficient halogen-bond donors (XB donors in XB catalysis) [23]. Despite their great

• potential in organic synthesis and catalysis, their structural variation is still limited. In particular, heteroarene-bridged cyclic iodonium salts are rare. Examples include the benzisoxazole-containing iodonium salt 1 described by Lisichkina and Tolstaya (Figure 1) [24][25]. Our group is interested in the

Continuous flow synthesis of 6-monoamino-6-monodeoxy-β-cyclodextrin

• János Máté Orosz,
• Dóra Ujj,
• Petr Kasal,
• Gábor Benkovics and
• Erika Bálint

Beilstein J. Org. Chem. 2023, 19, 294–302, doi:10.3762/bjoc.19.25

• ; monosubstitution; reduction; Introduction Cyclodextrins (CDs), as cyclic oligosaccharides, consist of a macrocyclic ring of glucose subunits linked by α-1,4-glycosidic bonds [1]. They are widely used in pharmaceutical, food and chemical industries, as well as in agriculture. It has been known for decades, that CD

Synthesis, α-mannosidase inhibition studies and molecular modeling of 1,4-imino-ᴅ-lyxitols and their C-5-altered N-arylalkyl derivatives

• Martin Kalník,
• Sergej Šesták,
• Juraj Kóňa,
• Maroš Bella and
• Monika Poláková

Beilstein J. Org. Chem. 2023, 19, 282–293, doi:10.3762/bjoc.19.24

• inverted via cyclic carbamate 21. Aminoalcohol 22 obtained after a basic hydrolysis of 21 was N-alkylated with the corresponding arylalkyl bromides to furnish derivatives 23–25. These were subjected to an acidic hydrolysis of the acetonide moiety to give the target compounds 26–28. Iminosugar 29 (6-deoxy

Strategies to access the [5-8] bicyclic core encountered in the sesquiterpene, diterpene and sesterterpene series

• Cécile Alleman,
• Charlène Gadais,
• Laurent Legentil and
• François-Hugues Porée

Beilstein J. Org. Chem. 2023, 19, 245–281, doi:10.3762/bjoc.19.23

An efficient metal-free and catalyst-free C–S/C–O bond-formation strategy: synthesis of pyrazole-conjugated thioamides and amides

• Shubham Sharma,
• Dharmender Singh,
• Sunit Kumar,
• Vaishali,
• Rahul Jamra,
• Naveen Banyal,
• Deepika,
• Chandi C. Malakar and
• Virender Singh

Beilstein J. Org. Chem. 2023, 19, 231–244, doi:10.3762/bjoc.19.22

• pyrazole-4-carbaldehydes 5–8 were found to be suitable substrates for this operation. It is pertinent to mention that the substrate 5 reacted with cyclic secondary amines A–C to yield the designed prototypes in moderate to good yields (49–76%), whereas thiomorpholine (D) delivered the thioamide conjugate

• for the construction of biologically interesting highly diversified pyrazole-linked thioamide and amide conjugates has been developed. The pyrazole C-3/4/5-tethered thioamide conjugates were prepared via a one-pot reaction between highly diversified pyrazole carbaldehydes, cyclic secondary amines, and

Insight into oral amphiphilic cyclodextrin nanoparticles for colorectal cancer: comprehensive mathematical model of drug release kinetic studies and antitumoral efficacy in 3D spheroid colon tumors

• Sedat Ünal,
• Gamze Varan,
• Juan M. Benito,
• Yeşim Aktaş and
• Erem Bilensoy

Beilstein J. Org. Chem. 2023, 19, 139–157, doi:10.3762/bjoc.19.14

• stable lactone form of encapsulated CPT due to their acidic chemical structure [8][9][11][13]. CDs are biocompatible cyclic polysaccharides formed by (1→4)-bound α-glucopyranose subunits obtained as a result of enzymatic degradation of starch by glucosyltransferase [21]. With their troncoconic structures