(Bio)isosteres of ortho- and meta-substituted benzenes

• H. Erik Diepers and
• Johannes C. L. Walker

Beilstein J. Org. Chem. 2024, 20, 859–890, doi:10.3762/bjoc.20.78

• substituted ortho-benzene. Stephenson and co-workers accessed 1,2-BCHeps 79a–c by insertion of alkenes into BCPs 78, and proposed the 1,2-BCHeps as isosteres of ortho-benzenes (Scheme 7A) [46]. The reaction proceeded via homolytic cleavage of a C–C bond adjacent to the imine functionality and stepwise alkene

Confirmation of the stereochemistry of spiroviolene

• Yao Kong,
• Yuanning Liu,
• Kaibiao Wang,
• Tao Wang,
• Chen Wang,
• Ben Ai,
• Hongli Jia,
• Guohui Pan,
• Min Yin and
• Zhengren Xu

Beilstein J. Org. Chem. 2024, 20, 852–858, doi:10.3762/bjoc.20.77

• either IM-9 or IM-11 cations. A direct dyotropic rearrangement, or two stepwise 1,2-alkyl migrations of IM-9, are possible pathways en route to cation IM-10. The presence of these intermediates IM-9, -10, -11 could be inferred by the identification of GJ1012B/D (5/6, Scheme 1D) [11], cattleyene (7) [19

Skeletal rearrangement of 6,8-dioxabicyclo[3.2.1]octan-4-ols promoted by thionyl chloride or Appel conditions

• Martyn Jevric,
• Julian Klepp,
• Johannes Puschnig,
• Oscar Lamb,
• Christopher J. Sumby and
• Ben W. Greatrex

Beilstein J. Org. Chem. 2024, 20, 823–829, doi:10.3762/bjoc.20.74

• work, which suggests a stepwise migration of oxygen from C5 to C4, followed by addition of the halogen nucleophile. Furthermore, if the halogen was involved in the transition state via the σ* orbital (avoiding intermediate 27), the opposite configuration would result at C2 in the products. The single

Regioselective quinazoline C2 modifications through the azide–tetrazole tautomeric equilibrium

• Dāgs Dāvis Līpiņš,
• Andris Jeminejs,
• Una Ušacka,
• Anatoly Mishnev,
• Māris Turks and
• Irina Novosjolova

Beilstein J. Org. Chem. 2024, 20, 675–683, doi:10.3762/bjoc.20.61

• % yield over 2 steps. The full conversion was achieved by keeping the reaction mixture at a temperature of 0 °C and by the stepwise additions of the sulfinate and NaN3. Any deviation from these conditions facilitated the formation of byproducts. In addition, the sulfonyl group dance reactions were carried

• product. Compounds 12 did not tolerate aqueous conditions or high temperatures and have also been observed to degrade under direct sunlight. Next, a stepwise one-pot approach was investigated to increase the overall yield (Scheme 6). The reaction in anhydrous DMF yielded a mixture of the desired product

Switchable molecular tweezers: design and applications

• Pablo Msellem,
• Maksym Dekthiarenko,
• Nihal Hadj Seyd and
• Guillaume Vives

Beilstein J. Org. Chem. 2024, 20, 504–539, doi:10.3762/bjoc.20.45

A new analog of dihydroxybenzoic acid from Saccharopolyspora sp. KR21-0001

• Rattiya Janthanom,
• Yuta Kikuchi,
• Hiroki Kanto,
• Tomoyasu Hirose,
• Arisu Tahara,
• Takahiro Ishii,
• Arinthip Thamchaipenet and
• Yuki Inahashi

Beilstein J. Org. Chem. 2024, 20, 497–503, doi:10.3762/bjoc.20.44

• minute) for 7 days. Purification and extraction The 7-day culture broth of Saccharopolyspora sp. KR21-0001 was centrifuged at 3000 rpm for 10 min. The supernatant fraction was eluted stepwise with 1.5 L of MeOH/H2O (0%, 50%, and 100%) through a HP20 column (55 i.d. × 500 mm), and all fractions were

Synthesis of π-conjugated polycyclic compounds by late-stage extrusion of chalcogen fragments

• Aissam Okba,
• Pablo Simón Marqués,
• Kyohei Matsuo,
• Naoki Aratani,
• Hiroko Yamada,
• Gwénaël Rapenne and
• Claire Kammerer

Beilstein J. Org. Chem. 2024, 20, 287–305, doi:10.3762/bjoc.20.30

• developed by Murata, Komatsu et al. [80]. In this approach, C60 or C70 fullerenes are modified stepwise towards an open-cage derivative in order to encapsulate small molecules such as H2 [81][82]. Eventually, the chemical modifications are reversed to close the hole and give an endohedral fullerene. As

• unambiguously proving the formation of tetracene 57. Importantly, the oxygen atoms extruded from precursor 56 were observed on the copper surface in close proximity to the converted molecule. In contrast with this tip-induced conversion of soluble precursor 56, which occurs stepwise and gives rise to one single

Catalytic multi-step domino and one-pot reactions

• Svetlana B. Tsogoeva

Beilstein J. Org. Chem. 2024, 20, 254–256, doi:10.3762/bjoc.20.25

• triggers the next, which in the end yields a complex product. In contrast to a conventional “stop-and-go” method, only a single workup and purification is needed (Figure 1b), and therefore these reaction cascades can be considered superior to stepwise synthetic approaches in the context of green chemistry

• . Zhang, Ma, and W. Zhang reflects the state of the art in the α-amino acid-based [3 + 2] cycloaddition reactions of N–H-type azomethine ylides in multicomponent, one-pot, and stepwise reactions for the synthesis of diverse bioactive heterocyclic compounds and natural products [9]. Computational studies

• through concerted or stepwise mechanisms. An enantioselective palladium-catalyzed three-component reaction of glyoxylic acid, sulfonamides, and aryltrifluoroborates toward synthetically useful α-arylglycine compounds is described by the Manolikakes group [11]. Moreover, Šebesta and co-workers report a

Metal-catalyzed coupling/carbonylative cyclizations for accessing dibenzodiazepinones: an expedient route to clozapine and other drugs

• Amina Moutayakine and
• Anthony J. Burke

Beilstein J. Org. Chem. 2024, 20, 193–204, doi:10.3762/bjoc.20.19

• cyclization with several other o-phenyldiamine derivatives, however, several impurities were obtained. In the hope of obtaining better yields (best obtained with the one pot method = 41%) we looked at the step-wise synthesis. Synthesis of 5,10-dihydro-11H-dibenzo[b,e][1,4]diazepin-11-ones via a stepwise Chan

•  4) [5]. The CF3- and COOEt-substituted DBDAs 4f and 4g were obtained with a slightly decreased yield of 55% and 40%, respectively. The N-methyldibenzodiazepine 4h could be accessed, but only in trace quantity. It should be noted that the stepwise approach was slightly better than the one-pot

• was via the Chan–Lam amination (milder conditions, cheaper, earth-abundant catalyst, no expensive ligand requirement) as the Buchwald–Hartwig amination required harsher conditions and an expensive metal catalyst, and also gave an unwanted phenazine side product. The sequential stepwise Chan–Lam

Perspectives on push–pull chromophores derived from click-type [2 + 2] cycloaddition–retroelectrocyclization reactions of electron-rich alkynes and electron-deficient alkenes

• Michio Yamada

Beilstein J. Org. Chem. 2024, 20, 125–154, doi:10.3762/bjoc.20.13

• beyond the scope of this review. Review Click-type [2 + 2] CA–RE reactions Click-type [2 + 2] CA–RE and associated reactions were comprehensively elucidated in a previous review [7]. Succinctly, the [2 + 2] CA reaction is postulated to be a stepwise process, whereas RE is postulated to be a concerted

• TCBD moiety was effectively integrated, as shown in Scheme 10 [110]. During this reaction, an intermediate 21 was successfully captured experimentally along with the occurrence of only the [2 + 2] CA reaction. Similarly, the reaction involving cyclooctadiyne (23) and TCNE progressed in a stepwise

Photoinduced in situ generation of DNA-targeting ligands: DNA-binding and DNA-photodamaging properties of benzo[c]quinolizinium ions

• Julika Schlosser,
• Olga Fedorova,
• Yuri Fedorov and
• Heiko Ihmels

Beilstein J. Org. Chem. 2024, 20, 101–117, doi:10.3762/bjoc.20.11

• bathochromic shifts of Δλ = 47–57 nm (Figure 3, Supporting Information File 1, Table S1), which indicated the formation of the benzo[c]quinolizinium ions 3c–g as photocyclization products [20]. The absence of isosbestic points during the photometric monitoring of the photoreactions indicated a stepwise

Identification of the p-coumaric acid biosynthetic gene cluster in Kutzneria albida: insights into the diazotization-dependent deamination pathway

• Seiji Kawai,
• Akito Yamada,
• Yohei Katsuyama and
• Yasuo Ohnishi

Beilstein J. Org. Chem. 2024, 20, 1–11, doi:10.3762/bjoc.20.1

• .). The protein was eluted using a stepwise gradient of imidazole in lysis buffer (20–500 mM imidazole). The buffer was replaced with lysis buffer using an Amicon Ultra centrifugal filter with a suitable molecular mass cutoff (Merck Millipore). Recombinant AvaA1 and AvaA3 obtained in our previous study

Long oligodeoxynucleotides: chemical synthesis, isolation via catching-by-polymerization, verification via sequencing, and gene expression demonstration

• Yipeng Yin,
• Reed Arneson,
• Alexander Apostle,
• Adikari M. D. N. Eriyagama,
• Komal Chillar,
• Emma Burke,
• Martina Jahfetson,
• Yinan Yuan and
• Shiyue Fang

Beilstein J. Org. Chem. 2023, 19, 1957–1965, doi:10.3762/bjoc.19.146

• results further confirmed that ODN damage by radicals during CBP purification is unlikely. Another concern for long ODN synthesis is the perceived low quantity of product [29]. For example, for a 400 nt ODN synthesis, if the average stepwise yield is 99.0% as usually observed in trityl assay for the

• ) indicated that it contained about 40 ng (0.14 pmol) ODN, which corresponds to a total yield of about 1% for the entire process of ODN synthesis, deprotection and cleavage, CBP purification, and other steps. The result is consistent with a stepwise yield of about 98.9% for ODN synthesis. According to trityl

• assay, the stepwise yield was 99.7%. This indicates that some ODNs were lost during CBP purification and other steps, which is reasonable. It is remarkable that we were successful in using only 1/1600 of the total ODNs we synthesized and purified by CBP (theoretically 1.5625 pmol) for PCR amplification

Decarboxylative 1,3-dipolar cycloaddition of amino acids for the synthesis of heterocyclic compounds

• Xiaofeng Zhang,
• Xiaoming Ma and
• Wei Zhang

Beilstein J. Org. Chem. 2023, 19, 1677–1693, doi:10.3762/bjoc.19.123

• -type AMYs in multicomponent, one-pot, and stepwise reactions for the synthesis of diverse heterocycles related to some bioactive compounds and natural products. Keywords: [3 + 2] cycloaddition; decarboxylation; 1,3-dipolar; double cycloaddition; one-pot synthesis; multicomponent reaction; semi

• aldehydes and alkenes. The first cycloaddition products 3c or 3d can also be used as intermediates for other transformations to synthesize novel heterocyclic rings via multicomponent, one-pot, and stepwise synthesis [63][64]. Presented in the following sections is our work on the development of amino acid

• -based decarboxylative [3 + 2] cycloadditions of N–H-type AMYs B3 and B4 for double cycloadditions. The stereochemistry of the cycloadditions and the combination of the cycloaddition with other transformations to be one-pot or stepwise reactions are also presented. Perspective One-step synthesis of

Sulfur-containing spiroketals from Breynia disticha and evaluations of their anti-inflammatory effect

• Ken-ichi Nakashima,
• Naohito Abe,
• Masayoshi Oyama,
• Hiroko Murata and
• Makoto Inoue

Beilstein J. Org. Chem. 2023, 19, 1604–1614, doi:10.3762/bjoc.19.117

• were concentrated in vacuo to yield the ethyl acetate fraction (11.8 g) and n-butanol fraction (7.4 g), respectively. The ethyl acetate fraction was separated by silica gel CC with CHCl3/MeOH (stepwise gradient of 100:1, 50:1, 30:1, 20:1, 15:1, 10:1, 8:1, and 0:1, v/v) as the eluent. The fractions were

• fractions were pooled by TLC analysis to yield four combined fractions (Frs. B1–B4). Fr. B2 was further separated on an ODS column eluted with MeOH/H2O (stepwise gradient of 2:3, 1:1, 3:2, and 1:0, v/v) to yield four combined subfractions. The second subfraction was separated by silica gel CC with ethyl

Secondary metabolites of Diaporthe cameroonensis, isolated from the Cameroonian medicinal plant Trema guineensis

• Bel Youssouf G. Mountessou,
• Élodie Gisèle M. Anoumedem,
• Blondelle M. Kemkuignou,
• Yasmina Marin-Felix,
• Frank Surup,
• Marc Stadler and
• Simeon F. Kouam

Beilstein J. Org. Chem. 2023, 19, 1555–1561, doi:10.3762/bjoc.19.112

• of this extract was subjected to a silica gel (230–400 mesh) column chromatography using a stepwise gradient of CH2Cl2/MeOH (ranging from 0 to 100% of MeOH, v/v), to afford a total of 8 main series (A–H) obtained on the basis of TLC analyses. However, series A (2.5 g) obtained with pure CH2Cl2 and

• : deionized water (H2O) + 0.1% formic acid (FA) and solvent B: acetonitrile (ACN) + 0.1% formic acid. The binary gradient was: linear of 5% B for 5 min, automatic stepwise gradient from 5 to 100% B for 5–105 min, followed by 100% B for 10 min wash, and finally by 80% ACN + 20% H2O for 10 min re-equilibration

Unraveling the role of prenyl side-chain interactions in stabilizing the secondary carbocation in the biosynthesis of variexenol B

• Moe Nakano,
• Rintaro Gemma and
• Hajime Sato

Beilstein J. Org. Chem. 2023, 19, 1503–1510, doi:10.3762/bjoc.19.107

• hyperconjugation determines whether the reaction proceeds in a stepwise or concerted manner. The second interesting aspect of the biosynthesis of variexenol B is that the biosynthetic pathway involves an intermediate with an exomethylene group. A terpene with an exomethylene group as a starting material is rare

• interacts with the secondary carbocation at C10, reducing the activation energy of the first step by approximately 4.7 kcal/mol. Moreover, due to the stabilization of the secondary carbocation-like intermediate IM2, the reaction proceeds stepwise rather than concertedly [7]. It was found that the final

Consecutive four-component synthesis of trisubstituted 3-iodoindoles by an alkynylation–cyclization–iodination–alkylation sequence

• Nadia Ledermann,
• Alae-Eddine Moubsit and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2023, 19, 1379–1385, doi:10.3762/bjoc.19.99

• synthesis of 1,2,5-trisubstituted 7-azaindoles [34]. Inspired by the coupling–cyclization–alkylation sequence and the stepwise Sonogashira coupling–cyclization–iodination protocol to give valuable 3-iodoindoles by Amjad and Knight [35], we reasoned that the interception by an electrophilic iodination step

Exploring the role of halogen bonding in iodonium ylides: insights into unexpected reactivity and reaction control

• Carlee A. Montgomery and
• Graham K. Murphy

Beilstein J. Org. Chem. 2023, 19, 1171–1190, doi:10.3762/bjoc.19.86

• intramolecular cyclopropanation of iodonium ylides (left); and, stepwise intermolecular cycloadditions with olefins (right). Concerted cycloaddition pathway for the metal-free, intramolecular cyclopropanation of iodonium ylides. Nucleophilic (top) and electrophilic (bottom) addition pathways proposed by Koser

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

• elimination of nitrous acid, accompanied by aromatization, yielded furan 13. In addition to the stepwise mechanism, a concerted ring-expansion can be also acceptable [25]. Conclusion Although nitrocyclopropanedicarboxylic acid esters 1a have been used in organic syntheses, nitrocyclopropanes possessing an

Construction of hexabenzocoronene-based chiral nanographenes

• Ranran Li,
• Di Wang,
• Shengtao Li and
• Peng An

Beilstein J. Org. Chem. 2023, 19, 736–751, doi:10.3762/bjoc.19.54

• stepwise Scholl reaction from 0 °C to room temperature by removing 84 hydrogens total. NG 128 is composed of seven HBCs and exhibit an extraordinary size, which reaches 3.50 nm in width and 1.25 nm in height. Single crystals X-ray diffraction indicates only one form (M or P) of enantiomer which can be

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

• phostams, phostones, and phostines are summarized. They include cyclizations and annulations. Cyclizations achieve ring construction through the formations of C–C, C–O, P–C, and P–O bonds in the rings, while annulations build the rings via [5 + 2], [6 + 1], and [7 + 1] fashions with the stepwise formation

• , and phostine derivatives through a stepwise bond formation fashion. To date, [5 + 2], [6 + 1], and [7 + 1] annulations have been developed for the synthesis of medium phostams and phostones. 2.1 Synthesis via [5 + 2] annulation A mixture of 2-phenyl/ethoxy-1-phenyl-1,2-dihydro-4H-benzo[d][1,3,2

Nostochopcerol, a new antibacterial monoacylglycerol from the edible cyanobacterium Nostochopsis lobatus

• Naoya Oku,
• Saki Hayashi,
• Yuji Yamaguchi,
• Hiroyuki Takenaka and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2023, 19, 133–138, doi:10.3762/bjoc.19.13

• MeOH to adjust its concentration to 60% (v/v). This was extracted with CH2Cl2 for three times, and the CH2Cl2-soluble layer was partitioned between aqueous 90% MeOH and n-hexane. The most active aqueous MeOH layer (113.3 mg) was subjected to ODS flash chromatography with a stepwise elution by MeCN/50

1,4-Dithianes: attractive C2-building blocks for the synthesis of complex molecular architectures

• Bram Ryckaert,
• Ellen Demeyere,
• Frederick Degroote,
• Hilde Janssens and
• Johan M. Winne

Beilstein J. Org. Chem. 2023, 19, 115–132, doi:10.3762/bjoc.19.12

• reported far less commonly than their use in (4 + 3) cycloadditions [94]. Simple hydrocarbon allyl cations can also undergo (3 + 2) cycloadditions through a purely stepwise cation olefin cyclization-type pathway, but these generally give complex mixtures and low yields and show unpredictable substrate

• suppress homodimerization, via a stepwise (3 + 2) cycloaddition of the initially generated cumyl cation across the olefin in amylene. Our group became intrigued by the potential of dihydrodithiins to act as carbocation-stabilizing groups, as these would represent a synthetic equivalent of ‘naked’ allyl

One-pot double annulations to confer diastereoselective spirooxindolepyrrolothiazoles

• Juan Lu,
• Bin Yao,
• Desheng Zhan,
• Zhuo Sun,
• Yun Ji and
• Xiaofeng Zhang

Beilstein J. Org. Chem. 2022, 18, 1607–1616, doi:10.3762/bjoc.18.171

•  2C). Results and Discussion The optimized reaction conditions of stepwise, one-pot and cascade (two-step with one operational step) processes for N,S-acetalation and decarboxylative 1,3-dipolar cycloaddition were developed by using two equivalents of 4-bromobenzaldehyde (1a), ʟ-cysteine (2) and

• purification from N,S-acetalation with 1.0:1.15 of 1a/2 at 25 °C for 6 h with EtOH as solvent, in situ followed by addition of 1.1:1.0 of 1a/4a for [3 + 2] cycloaddition at 90 °C for 9 h gave compound 5a with the 81% of LC yield. Next, the stepwise process was also carried out by using the thioproline 3a (1

• stereocenters and two heterocycles in a diastereoselective fashion, and without intermediate purification. The one-pot four-component synthesis in green metrics analysis is compared with the stepwise reaction process to pinpoint the overwhelming advantages of the one-pot approach in the CE, MP, PMI, and SI by