Rapid construction of tricyclic tetrahydrocyclopenta[4,5]pyrrolo[2,3-b]pyridine via isocyanide-based multicomponent reaction

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

Beilstein J. Org. Chem. 2024, 20, 1436–1443, doi:10.3762/bjoc.20.126

• -deficient alkynes [59][60][61][62][63]. The in situ generated cyclic intermediate C has a resonance hybrid C’. Then, the further nucleophilic addition of the electron-rich enamino unit to 5-(alkylimino)cyclopenta-1,3-diene intermediate C gave intermediate D. At last, the coupling of the iminium cation with

Synthesis of cyclic β-1,6-oligosaccharides from glucosamine monomers by electrochemical polyglycosylation

• Md Azadur Rahman,
• Hirofumi Endo,
• Takashi Yamamoto,
• Shoma Okushiba,
• Norihiko Sasaki and
• Toshiki Nokami

Beilstein J. Org. Chem. 2024, 20, 1421–1427, doi:10.3762/bjoc.20.124

• , Tottori University, 4-101 Koyamacho-minami, Tottori city, 680-8552 Tottori, Japan 10.3762/bjoc.20.124 Abstract The synthesis of protected precursors of cyclic β-1,6-oligoglucosamines from thioglycosides as monomers is performed by electrochemical polyglycosylation. The monomer with a 2,3-oxazolidinone

• protecting group afforded the cyclic disaccharide exclusively. Cyclic oligosaccharides up to the trisaccharide were obtained using the monomer with a 2-azido-2-deoxy group. Keywords: cyclic oligosaccharide; electrochemical glycosylation; glucosamine; polyglycosylation; Introduction Electrochemical

• reactions. Therefore, electrochemical polymerizations can be utilized for selective synthesis. Cyclic oligosaccharides are an important class of host molecules, and some natural cyclic oligosaccharides are produced by enzymatic processes. However, the corresponding chemical syntheses are still primitive [6

Challenge N- versus O-six-membered annulation: FeCl₃-catalyzed synthesis of heterocyclic N,O-aminals

• Giacomo Mari,
• Lucia De Crescentini,
• Gianfranco Favi,
• Fabio Mantellini,
• Diego Olivieri and
• Stefania Santeusanio

Beilstein J. Org. Chem. 2024, 20, 1412–1420, doi:10.3762/bjoc.20.123

• a new example of cyclic N,O-aminals and carbinolamine derivatives, an interesting class of organic compounds that are common structural motifs embedded within diverse biologically important natural products and pharmaceuticals [32][33][34][35][36][37]. On the other hand, the N,O-aminals are stable

Generation of alkyl and acyl radicals by visible-light photoredox catalysis: direct activation of C–O bonds in organic transformations

• Mithu Roy,
• Bitan Sardar,
• Itu Mallick and
• Dipankar Srimani

Beilstein J. Org. Chem. 2024, 20, 1348–1375, doi:10.3762/bjoc.20.119

• optimized or slightly modified conditions, cyclic secondary, and tertiary alkyl carboxylic acids were smoothly coupled with 1,1-diphenylethylene to give 3i–m. α,α′-Diarylated ketones serve as crucial building blocks in the construction of both natural and synthetic compounds with significant biological

• iodide leads to the formation of 23, which further undergoes 5-endo-trig cyclization, followed by fragmentation to produce an alkyl radical and a cyclic thiocarbonate 25. These alkyl radicals then interact with B2cat2 (19) to produce a variety of structurally intricate boronic esters. The reaction occurs

• final reductive elimination gives the desired alkene and Ni(I). The two catalytic cycles are finally completed by single-electron reduction of [Ni(I)] by [Ir(II)], which regenerates [Ni(0)] and ground-state [Ir(III)]. Cyclic oxalates readily form the corresponding alkyl radicals under iridium

Diameter-selective extraction of single-walled carbon nanotubes by interlocking with Cu-tethered square nanobrackets

• Guoqing Cheng and
• Naoki Komatsu

Beilstein J. Org. Chem. 2024, 20, 1298–1307, doi:10.3762/bjoc.20.113

• ) acetylacetonate, the nanobracket 4b and HiPco SWNTs were bath-sonicated for 9 h in 2-propanol. Meanwhile, 4b is assumed to form complexes with SWNTs. After copper(II) acetylacetonate was added to the mixture, the cyclic Cu-nanobrackets 1b would be formed to interlock SWNTs with appropriate diameters during

• mechanically interlocking cyclic molecules are reported not to be removed with washing [11][22][23][24]. In addition, these Raman signals of 1b shift to higher frequencies at e- and i-SWNTs, similarly to our previous report [11], probably due to the structural change of Cu-nanobrackets 1b, or the energy

• transfer between the interlocked SWNTs and the cyclic Cu-nanobrackets. After thorough removal of the host molecules with DTT, weak signals are remained at p-SWNTs, known as intermediate frequency modes (IFM) of SWNTs [25]. The IFM signals are also observed in e- and i-SWNTs, showing the coexistence of both

Phenotellurazine redox catalysts: elements of design for radical cross-dehydrogenative coupling reactions

• Alina Paffen,
• Christopher Cremer and
• Frederic W. Patureau

Beilstein J. Org. Chem. 2024, 20, 1292–1297, doi:10.3762/bjoc.20.112

• this reaction: PTeZ1 (3aa, 73% after 3 h). In other words, the cyclic phenotellurazine character of the catalyst does not seem to be essential in the context of this particular reaction, as opposed to the ortho/para substitution pattern of Te- and N-atoms. Nevertheless, all results considered, we

• elected at this point to keep the cyclic phenotellurazine structure of the catalyst in the hope of increased catalytic robustness, especially in view of further increasing substitution. Next, we therefore tested methoxy-substituted PTeZ2, a successful catalyst structure which we recently developed for the

Synthesis of indano[60]fullerene thioketone and its application in organic solar cells

• Yong-Chang Zhai,
• Shimon Oiwa,
• Shinobu Aoyagi,
• Shohei Ohno,
• Tsubasa Mikie,
• Jun-Zhuo Wang,
• Hirofumi Amada,
• Koki Yamanaka,
• Kazuhira Miwa,
• Naoyuki Imai,
• Takeshi Igarashi,
• Itaru Osaka and
• Yutaka Matsuo

Beilstein J. Org. Chem. 2024, 20, 1270–1277, doi:10.3762/bjoc.20.109

• molecular orbital (LUMO). To understand the electron affinity of t-Bu-FIDS, cyclic voltammetry was conducted. The cyclic voltammogram of t-Bu-FIDS in o-DCB showed reversible reduction waves at E1/2 = −1.14 V and −1.51 V (vs Fc/Fc+), as shown in Figure 3. Both the first and second reduction potentials of t

• -Bu-FIDS (black) and of toluene used to rinse the evaporated film of t-Bu-FIDS (red). Single-crystal structure of t-Bu-FIDS. (a) The π–π distance between two molecules. (b) Crystal packing. Cyclic voltammograms of fullerene derivatives in o-DCB solution containing Bu4N+(CF3SO2)2N− (0.1 M) as

Competing electrophilic substitution and oxidative polymerization of arylamines with selenium dioxide

• Vishnu Selladurai and
• Selvakumar Karuthapandi

Beilstein J. Org. Chem. 2024, 20, 1221–1235, doi:10.3762/bjoc.20.105

• , Supporting Information File 1). It allowed the molecule to self-align in a repeating cyclic ring pattern in one dimension. The molecular structure of the diorganyl monoselenide 12 is shown in Figure 6. It crystallized in an orthorhombic crystal system in the space group P21212. The C–Se–C bond angle was

Introduction of peripheral nitrogen atoms to cyclo-meta-phenylenes

• Koki Ikemoto and
• Hiroyuki Isobe

Beilstein J. Org. Chem. 2024, 20, 1207–1212, doi:10.3762/bjoc.20.103

• best and afforded cyclic congeners from N3-[6]CMP to N6-[12]CMP (Figure S1, Supporting Information File 1) and isolated N3-[6]CMP (3a) and N4-[8]CMP (3b) in 7% and 3% yields, respectively [14]. Comparisons of the UV–vis spectra of the doped and undoped congeners revealed dopant-induced changes in the

Stability trends in carbocation intermediates stemming from germacrene A and hedycaryol

• Naziha Tarannam,
• Prashant Kumar Gupta,
• Shani Zev and
• Dan Thomas Major

Beilstein J. Org. Chem. 2024, 20, 1189–1197, doi:10.3762/bjoc.20.101

• from germacrene A or hedycaryol are categorized depending upon the formation of (6,6) or (5,7) cyclic rings. Deprotonations of A at the C3 and C15 positions lead to α-selinene [18] and β-selinene [19]. Sesquiterpenes arising through B occur less frequently in nature compared to the A derivatives

Two-fold addition reaction of silylene to C₆₀: structural and electronic properties of a bis-adduct

• Masahiro Kako,
• Masato Kai,
• Masanori Yasui,
• Michio Yamada,
• Yutaka Maeda and
• Takeshi Akasaka

Beilstein J. Org. Chem. 2024, 20, 1179–1188, doi:10.3762/bjoc.20.100

• of 1 with the HOMO of 2a should be considered. Electrochemical measurements of 3 Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) measurements were conducted to evaluate the electronic effects of the silylene addends in 3 (Figure 9). The oxidation processes of 3 were shown to be

• . Reagents were used as purchased unless otherwise specified. The 1H and 13C NMR measurements were conducted on a JEOL ECA-500 spectrometer (JEOL Ltd.). Absorption spectra were measured using a UV-3150 spectrophotometer (Shimadzu Corp.). Cyclic voltammograms and differential pulse voltammograms were recorded

• /ferrocenium couple (Fc/Fc+) as the standard. (n-Bu)4NPF6 (0.1 M) in ODCB was used as the supporting electrolyte solution. The cyclic voltammograms were recorded using a scan rate of 50 mV/s. The differential pulse voltammograms were obtained using a pulse amplitude of 50 mV, a pulse width of 50 ms, a pulse

Manganese-catalyzed C–C and C–N bond formation with alcohols via borrowing hydrogen or hydrogen auto-transfer

• Mohd Farhan Ansari,
• Atul Kumar Maurya,
• Abhishek Kumar and
• Saravanakumar Elangovan

Beilstein J. Org. Chem. 2024, 20, 1111–1166, doi:10.3762/bjoc.20.98

• ]. Symmetrical, unsymmetrical, and cyclic azoarenes were studied with benzyl alcohol using catalyst Mn9 (5 mol %) and t-BuOK (2 equiv) at 130 °C for 24 h in octane, resulting in the corresponding N-alkylated amines with up to 96% yield (Scheme 19). On the other hand, various aromatic and aliphatic primary and

• compound E. Cyclization occurred via dehydrogenation and intramolecular aldol condensation and in the last step hydrogen transfer provided the desired cyclic product H (Scheme 35). In 2020, Maji and Adhikari reported a phosphine-free N,N-amine–manganese complex-catalyzed stereoselective intermolecular and

• -membered ring products. They isolated cyclic five to seven-membered ring products by changing the lengths of the diols. For example, for the formation of cyclopentane products, butane-1,4-diol was used as the alcohol under the same reaction conditions, giving 31 to 70% yield of the desired products. Seven

Light on the sustainable preparation of aryl-cored dibromides

• Fabrizio Roncaglia,
• Alberto Ughetti,
• Nicola Porcelli,
• Biagio Anderlini,
• Andrea Severini and
• Luca Rigamonti

Beilstein J. Org. Chem. 2024, 20, 1076–1087, doi:10.3762/bjoc.20.95

• molecular wires or extended structures – either linear or cyclic – with enhanced functionality. Consequently, they play a crucial role in the fabrication of polymers [4][5][6][7], cyclophanes [8], photoactive materials [9][10][11], membranes [12], and other architectures. The synthetic potential of aryl

Novel route to enhance the thermo-optical performance of bicyclic diene photoswitches for solar thermal batteries

• Akanksha Ashok Sangolkar,
• Rama Krishna Kadiyam and
• Ravinder Pawar

Beilstein J. Org. Chem. 2024, 20, 1053–1068, doi:10.3762/bjoc.20.93

• solvents on the photoswitching properties has also been investigated for a real-life MOST application. The stability and the reversibility of the photoswitches have also been verified to attain a closed cyclic photoswitching process for practical MOST system. Results and Discussion As can be seen from

Structure–property relationships in dicyanopyrazinoquinoxalines and their hydrogen-bonding-capable dihydropyrazinoquinoxalinedione derivatives

• Tural N. Akhmedov,
• Ajeet Kumar,
• Daken J. Starkenburg,
• Kyle J. Chesney,
• Khalil A. Abboud,
• Novruz G. Akhmedov,
• Jiangeng Xue and
• Ronald K. Castellano

Beilstein J. Org. Chem. 2024, 20, 1037–1052, doi:10.3762/bjoc.20.92

• obtained from absorbance spectra, taken as the photon energy corresponding to the cut-off wavelength (Table 1). Subsequently, preliminary electrochemical studies were performed with selected DCPQs and corresponding DPQD counterparts using cyclic voltammetry (Figure S1, Supporting Information File 1

• ). Cyclic voltammetric measurements of DCPQs, specifically 4a and 6a, and DPQDs 4b and 6b, support the overall trends observed through the electronic structure calculations. X-ray crystallography Single crystal X-ray diffraction data could be obtained for 2b, 5b, and 6b. Figure 6 illustrates the single

Carbonylative synthesis and functionalization of indoles

• Alex De Salvo,
• Raffaella Mancuso and
• Xiao-Feng Wu

Beilstein J. Org. Chem. 2024, 20, 973–1000, doi:10.3762/bjoc.20.87

• in CH3CN (Scheme 11). Another interesting example concerns the synthesis of 1,2-dihydro-4(3H)-carbazolones by a Pd(0)-catalyzed N-heteroannulation of functionalized 2-nitrostyrenes [26]. Pd(dba)2 was able to catalyze the reaction because a five-membered Pd(II)-cyclic species could be formed, favored

• hexaketocyclohexane octahydrate as the CO source again. This cyclic hexaketone is a non-toxic stable solid and therefore, it is simple and safe to use unlike of carbon monoxide. It was used as reagent to obtain indol-α-ketoesters by the Cu-catalyzed direct double-carbonylation of indoles and alcohols [76]. The

Enhancing structural diversity of terpenoids by multisubstrate terpene synthases

• Min Li and
• Hui Tao

Beilstein J. Org. Chem. 2024, 20, 959–972, doi:10.3762/bjoc.20.86

• converted into (poly)cyclic skeletons, including hemiterpenes, monoterpenes, sesquiterpenes, diterpenes, sesterterpenes, and triterpenes, by a large class of enzymes called terpene synthases (TSs) (Figure 1). The reactions of TSs are one of the most important factors contributing to terpene diversity, as

• different subcellular compartments may facilitate the generation of multiple terpenoids in plants. Recently, in addition to linear terpenoid-producing TSs, MSTSs that form cyclic terpenoids have been discovered in plants, further increasing our understanding of chemodiversity and biosynthesis of plant

• terpenoids with diverse cyclic structures and important biological activities, which are of great interest. However, the number of known fungal MSTSs is currently limited, and researchers have focused on the promiscuity of their products rather than substrates [25][26][27]. Unlike plant MSTSs, fungal MSTSs

Enantioselective synthesis of β-aryl-γ-lactam derivatives via Heck–Matsuda desymmetrization of N-protected 2,5-dihydro-1H-pyrroles

• Arnaldo G. de Oliveira Jr.,
• Martí F. Wang,
• Rafaela C. Carmona,
• Danilo M. Lustosa,
• Sergei A. Gorbatov and
• Carlos R. D. Correia

Beilstein J. Org. Chem. 2024, 20, 940–949, doi:10.3762/bjoc.20.84

• complexity in a synthetic route. The palladium-catalyzed coupling of arenediazonium salts with olefins, the Heck–Matsuda reaction, has been instrumental in this strategy involving the desymmetrization of cyclic systems [3], especially five-membered substrates [4][5][6][7]. As we have demonstrated previously

Ortho-ester-substituted diaryliodonium salts enabled regioselective arylocyclization of naphthols toward 3,4-benzocoumarins

• Ke Jiang,
• Cheng Pan,
• Limin Wang,
• Hao-Yang Wang and
• Jianwei Han

Beilstein J. Org. Chem. 2024, 20, 841–851, doi:10.3762/bjoc.20.76

• Technology, 130 Meilong Road, Shanghai 200237, P. R. China National Center for Organic Mass Spectrometry in Shanghai, Shanghai Institute of Organic Chemistry, The Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China 10.3762/bjoc.20.76 Abstract Cyclic annulation involving diaryliodonium

• have been employed in benzocyclization and arylocyclization reactions, enabling intramolecular cyclization by forming aromatic or heterocyclic rings as a part of cyclic structures [8]. In these reactions, the dual activation of a C–I bond and vicinal C–H bonds/functional groups features a distinct

Activity assays of NnlA homologs suggest the natural product N-nitroglycine is degraded by diverse bacteria

• Kara A. Strickland,
• Brenda Martinez Rodriguez,
• Ashley A. Holland,
• Shelby Wagner,
• Michelle Luna-Alva,
• David E. Graham and
• Jonathan D. Caranto

Beilstein J. Org. Chem. 2024, 20, 830–840, doi:10.3762/bjoc.20.75

• protect bacteria from exposure to NNG. Keywords: enzymology; natural products; nitramine; N–N bond; Introduction Degradation of nitramines (R–N(R′)NO2; R′ = H or alkyl) has been well studied in the context of the environmental degradation of explosive cyclic nitramines [1][2]. The cyclic nitramines

• hexahydro-1,3,5-trinitro-1,3,5-triazine (commonly called RDX), octogen (HMX), and hexanitrohexaazaisowurtzitane (CL-20) are compounds found in military grade explosives and propellants. Contamination of these cyclic nitramines in soil and groundwater is concerning due to their toxicity and potential

• carcinogenicity [3][4][5][6][7][8]. Biotic and abiotic degradation of cyclic nitramines often produce linear nitramine byproducts. For example, degradation of RDX and HMX by microbes or alkaline hydrolysis forms the linear nitramine 4-nitro-2,4-diazabutanal (NDAB) [9][10][11][12]. Linear nitramines are also

Methodology for awakening the potential secondary metabolic capacity in actinomycetes

• Shun Saito and
• Midori A. Arai

Beilstein J. Org. Chem. 2024, 20, 753–766, doi:10.3762/bjoc.20.69

• defensive compounds as a countermeasure. Therefore, the pathogenic actinomycetes were co-cultured with J774.1 mouse macrophage-like cells (Figure 5b). The first compound isolated was nocarjamide (52), a cyclic nonapeptide, discovered by co-culturing Nocardia tenerifensis IFM 10554T with J774.1 cells [121

Chemoenzymatic synthesis of macrocyclic peptides and polyketides via thioesterase-catalyzed macrocyclization

• Senze Qiao,
• Zhongyu Cheng and
• Fuzhuo Li

Beilstein J. Org. Chem. 2024, 20, 721–733, doi:10.3762/bjoc.20.66

• peptides and even small proteins. In the chemoenzymatic synthesis of macrocyclic peptides, SPPS strategies provide highly efficient routes to access linear precursors, accelerating the development of enzymatic macrocyclization. The tyrocidines Tyrocidine A (1), a cyclic decapeptide isolated from Bacillus

• several positions and also form 6–14 residue cyclic peptides [37][38]. It should be noted that TycC TE was more sensitive to the amino acid changes near the site of ring closure. The alkyne-containing analogs were conjugated to a variety of azido sugars via copper(I)-catalyzed cycloaddition to obtain the

• gramicidin S synthetase GrsB [44]. Combined with the peptidyl carrier protein, GrsB PCP-TE was tested by using corresponding pentapeptides NAC thioester and thiophenol thioester, which led to the formation of the desired cyclic decapeptide lactam gramicidin S (9) through a sequential dimerization and

SOMOphilic alkyne vs radical-polar crossover approaches: The full story of the azido-alkynylation of alkenes

• Julien Borrel and
• Jerome Waser

Beilstein J. Org. Chem. 2024, 20, 701–713, doi:10.3762/bjoc.20.64

• cyclic substrate 1i did not afford the desired product. Although β-substitution on the alkene is tolerated, using trans-stilbene only afforded 24% yield. Unfortunately, aliphatic alkenes are not tolerated in the reaction. When 1k was used no product was formed and only partial conversion was observed. As

Palladium-catalyzed three-component radical-polar crossover carboamination of 1,3-dienes or allenes with diazo esters and amines

• Geng-Xin Liu,
• Xiao-Ting Jie,
• Ge-Jun Niu,
• Li-Sheng Yang,
• Xing-Lin Li,
• Jian Luo and
• Wen-Hao Hu

Beilstein J. Org. Chem. 2024, 20, 661–671, doi:10.3762/bjoc.20.59

• , different alkylamines with various functional groups were evaluated under the optimized conditions, successfully delivering the corresponding 1,4-difunctionalized products in moderate to excellent yields (4a–k, 35–84%) with high regioselectivity. Some simple secondary amines including cyclic amines 3a, 3c

Enhanced reactivity of Li⁺@C₆₀ toward thermal [2 + 2] cycloaddition by encapsulated Li⁺ Lewis acid

• Hiroshi Ueno,
• Yu Yamazaki,
• Hiroshi Okada,
• Fuminori Misaizu,
• Ken Kokubo and
• Hidehiro Sakurai

Beilstein J. Org. Chem. 2024, 20, 653–660, doi:10.3762/bjoc.20.58

• yield of multiadducts compared to previously reported functionalizations of Li+@C60. The reason can be explained by the difference in electron-accepting ability between the monoadduct and pristine Li+@C60 investigated by cyclic voltammetry (Figure 5). Both products exhibited reversible first and second

• Shimadzu UV-1800 spectrophotometer. Cyclic voltammograms were recorded on a BAS ALS 600A and a BAS ALS 620D apparatus with a three-electrode system. Reactivitiy comparison of Li+@C60 TFSI− and styrenes In an Ar-filled glove box, Li+@C60 TFSI− and styrenes 1–4 were dissolved in anhydrous chlorobenzene. 100

• photoirradiation at room temperature. 1H-1H 2D-NOESY NMR spectrum (600 MHz, CD2Cl2) of 5a (a) and NOE correlations between two protons. The spectrum (700 MHz, CD2Cl2) of 5b is shown in (b). Cyclic voltammograms of 5a, 5b, and Li+@C60 TFSI− with the potentials relative to the ferrocene/ferrocenium (Fc/Fc