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

• refluxing acetonitrile for 6 h. It underwent a radical cyclization in refluxing benzene for 20 h to give rise to a nine-membered phostone thieno[2,3-d]pyrimidine-fused 2-hydroxy-1,2-oxaphosphonane 2-oxide 46 as a potential inhibitor after the deprotection of the benzyl group in the presence of DABCO in

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

• were obtained in good yields regardless of the substituent R in the benzene ring. Treatment of the latter with fluoroboric acid in dichloromethane gave double salts 11a–e. X-ray structures Slow evaporation of solutions of butadiynes 5 in the CHCl3/EtOAc system made it possible to grow single crystals

• , including naphthalene cores, butadiyne and acetylene linkers. The main structural parameters of diynes 5 that characterize the degree of this distortion are presented in Table 2, where ϕ1 is the angle between the planes of the benzene ring and the neighboring naphthalene system, ϕ2 is the angle between the

• DMAN fragments do not participate in nonvalent interactions and do not form short contacts. The recurring motif in the crystals is the coordination of the benzene meta proton by the nitrogen atom of the C≡N group. The structural parameters of both monomer fragments of nitro derivative 5e are identical

pH-Responsive fluorescent supramolecular nanoparticles based on tetraphenylethylene-labelled chitosan and a six-fold carboxylated tribenzotriquinacene

• Nan Yang,
• Yi-Yan Zhu,
• Wei-Xiu Lin,
• Yi-Long Lu and
• Wen-Rong Xu

Beilstein J. Org. Chem. 2023, 19, 635–645, doi:10.3762/bjoc.19.45

• display distinct peaks at δ 7.50–6.70 in their 1H NMR spectra (Figure 1) and at δ 145–120 ppm in their 13C NMR spectra (Figure S1 in Supporting Information File 1), corresponding to the proton resonances of the benzene rings and the carbon resonances of the whole fluorophore, respectively. The appearance

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

• naphthylation of oxabenzonorbornadienes 30 with N-sulfonyl 2-aminobenzaldehydes 172 (Scheme 30) [76]. This reaction was amenable to a variety of EDG, EWG, as well as a broad scope of sulfonyl groups. Surprisingly, this reaction also proceeded smoothly with nitro substituents on the benzene ring which are

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

• targeted compounds aiming to reach higher overall yields and fewer steps [55]. The monobenzylation [56] of aldehyde 67 followed by chain elongation using a Wittig reaction gave compound 68, which was submitted to the hydrogenation of the double bond. The use of benzene as solvent in the hydrogenation step

CuAAC-inspired synthesis of 1,2,3-triazole-bridged porphyrin conjugates: an overview

• Dileep Kumar Singh

Beilstein J. Org. Chem. 2023, 19, 349–379, doi:10.3762/bjoc.19.29

• the synthesis of the novel 1,3,5-benzene-centered and triazole-bridged porphyrin star trimer 129 (Scheme 25) in 30% yield via CuAAC click reaction. In the UV–vis absorption spectrum, the absorption bands of product trimer 129 and starting compound 127 were almost coincided with each other, which

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

• . Ltd., and used without further purification. Commercially available anhydrous solvents (THF, DMF, benzene, toluene, MeOH, EtOH, and CH2Cl2 Spectrochem) were used in the reactions. Thin-layer chromatography (TLC) was performed using precoated aluminum plates purchased from E. Merck (silica gel 60 PF254

Friedel–Crafts acylation of benzene derivatives in tunable aryl alkyl ionic liquids (TAAILs)

• Swantje Lerch,
• Stefan Fritsch and
• Thomas Strassner

Beilstein J. Org. Chem. 2023, 19, 212–216, doi:10.3762/bjoc.19.20

• Swantje Lerch Stefan Fritsch Thomas Strassner Professur für Physikalische Organische Chemie, Technische Universität Dresden, 01062 Dresden, Germany 10.3762/bjoc.19.20 Abstract An iron(III) chloride hexahydrate-catalyzed Friedel–Crafts acylation of benzene derivatives in tunable aryl alkyl ionic

• protocols using different metal salts [25][26][27][28][29][30] and ionic liquids [31][32][33][34][35] to acylate [36][37][38][39][40][41], alkylate [42][43][44], benzylate [45][46][47] and alkenylate [48][49] different benzene derivatives. But surprisingly, a robust protocol using commercially available and

• lithium bis(trifluoromethylsulfonyl)imide (LiNTf2). All reactions are generally tolerant towards different aryl substitutions, substitution patterns, alkyl chain lengths and can be carried out in a multigram scale [57]. The acylation of the electron-rich benzene derivative anisole with acetic anhydride

Sequential hydrozirconation/Pd-catalyzed cross coupling of acyl chlorides towards conjugated (2E,4E)-dienones

• Benedikt Kolb,
• Daniela Silva dos Santos,
• Sanja Krause,
• Anna Zens and
• Sabine Laschat

Beilstein J. Org. Chem. 2023, 19, 176–185, doi:10.3762/bjoc.19.17

• solvent but is not necessarily required in the subsequent steps. When the reaction was carried out in benzene, CH2Cl2 or dioxane, much lower yields of 28%, 31%, and 8%, respectively, were obtained (Table 2, entries 2–4). Toluene gave the best yield with 55% (Table 2, entry 5). Therefore, further

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

• access to building block 2. The benzannelated series of 1,4-dithiane heterocycles 5–7 can in principle be obtained using Parham’s α-halocarbonyl condensation and rearrangement approach, starting from benzene-1,2-dithiol. More conveniently, however, ethanedithiol and cyclohexanone can be condensed, and

• helpful when dealing with sensitive dienes. A nice illustration of this is afforded by De Lucchi’s simple synthesis of barrelene (33) from oxepin (29, Scheme 8b) [52]. Oxepin’s equally unstable valence tautomer 30 (benzene oxide) is quite reactive as a diene in Diels–Alder reactions, and can react with 7

Two-step continuous-flow synthesis of 6-membered cyclic iodonium salts via anodic oxidation

• Julian Spils,
• Thomas Wirth and
• Boris J. Nachtsheim

Beilstein J. Org. Chem. 2023, 19, 27–32, doi:10.3762/bjoc.19.2

• with only two equivalents of TfOH forming product 1a in 74% yield (Table 2, entry 1). We found that these reaction conditions cannot be applied in the proposed multi-step procedure since the added benzene clogs the flow reactor through precipitation of a black solid. We could overcome this issue by

• decomposition of the intermediary iodoarene. Here it was possible to perform the procedure with either benzene or toluene, leading to a moderate yield of 38% and 37%. We could not use derivatives with any other substituents with secondary benzyl acetates since those led only to inseparable product mixtures

Rhodium-catalyzed intramolecular reductive aldol-type cyclization: Application for the synthesis of a chiral necic acid lactone

• Motoyuki Isoda,
• Kazuyuki Sato,
• Kenta Kameda,
• Kana Wakabayashi,
• Ryota Sato,
• Hideki Minami,
• Yukiko Karuo,
• Atsushi Tarui,
• Kentaro Kawai and
• Masaaki Omote

Beilstein J. Org. Chem. 2022, 18, 1642–1648, doi:10.3762/bjoc.18.176

• relative configurations of syn-2a and anti-2a were confirmed by X-ray crystallography. In addition, a NOESY experiment of the product syn-2a showed an nOe correlation between the methine proton on Cα and one of the protons of the benzene ring on Cβ, but not in anti-2a. Next, various substrates were

• complex derived from [RhCl(cod)]2 and Et2Zn played an important role in this reaction [48]. Furthermore, Hopmann et al. detected the Rh–H complex derived from [RhCl(cod)]2 and Et2Zn by 1H NMR, and the detailed mechanism disclosed that the Rh–H complex did not interact with CO2 but with the benzene ring in

• complex 5 from [RhCl(cod)]2 and Et2Zn would generate predominantly the corresponding E-enolate 6 via 1,4-reduction, which is stabilized through η6 binding with benzene ring of the substrate. Subsequent transmetalation with zinc species 4 readily reacts with the carbonyl group to form the intramolecular C

Formal total synthesis of macarpine via a Au(I)-catalyzed 6-endo-dig cycloisomerization strategy

• Jiayue Fu,
• Bingbing Li,
• Zefang Zhou,
• Maosheng Cheng,
• Lu Yang and
• Yongxiang Liu

Beilstein J. Org. Chem. 2022, 18, 1589–1595, doi:10.3762/bjoc.18.169

• ]phenanthridine skeleton consists of a phenanthridine (rings A, B, C) and a benzene (ring D), and most of the synthetic routes were completed in the last step by constructing ring B or ring C. Some representative examples and their key strategies are summarized in Scheme 2. In 1989, Hanaoka and co-workers

• ). The Au(I)-catalyzed cycloisomerization reaction of substrate 10 occurred under the catalysis of 5 mol % [1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene]gold(I) chloride (IPrAuCl) and 5 mol % silver hexafluoroantimonate (AgSbF6) [25][26] in anhydrous DCM at room temperature for 2 h forming a benzene

Comparison of crystal structure and DFT calculations of triferrocenyl trithiophosphite’s conformance

• Ruslan P. Shekurov,
• Mikhail N. Khrizanforov,
• Ilya A. Bezkishko,
• Tatiana P. Gerasimova,
• Almaz A. Zagidullin,
• Daut R. Islamov and
• Vasili A. Miluykov

Beilstein J. Org. Chem. 2022, 18, 1499–1504, doi:10.3762/bjoc.18.157

• vacuo. The product was extracted with benzene (3 × 30 mL) and after evaporation of the solvent triferrocenyl trithiophosphite (1.34 g, 76%) was obtained as a yellow powder. Single crystals suitable for X-ray diffraction were obtained by dissolving the compound in a mixture of benzene/hexane 1:1 and

One-pot synthesis of 2-arylated and 2-alkylated benzoxazoles and benzimidazoles based on triphenylbismuth dichloride-promoted desulfurization of thioamides

• Arisu Koyanagi,
• Yuki Murata,
• Shiori Hayakawa,
• Mio Matsumura and
• Shuji Yasuike

Beilstein J. Org. Chem. 2022, 18, 1479–1487, doi:10.3762/bjoc.18.155

• reaction of o-alkoxythiobenzamides with iodine in the presence of sodium hydride as the base [11]. Sugita et al. reported an unstable iodoalkyne, pentafluoro(iodoethynyl)benzene, which catalyzed the cyclization of thioamides with 2-aminophenol [12]. These approaches have some drawbacks, such as low yields

• electron-donating or electron-withdrawing groups on the phenyl rings (R2) afforded the corresponding 2-arylbenzoxazoles 8b–g in good to excellent yields (79–99%). The nature of substituents on the benzene rings of the thioamides did not significantly affect the reaction outcome. Sterically hindered

• with aminophenol 1a to afford the 2-alkylbenzoxazoles 8l and 8m. Various aminophenols bearing different electron-donating and electron-withdrawing groups at the 4-position of the benzene ring were treated with 2a and 6a to afford the corresponding products 8n–r in good to excellent yields. Subsequently

Sinensiols H–J, three new lignan derivatives from Selaginella sinensis (Desv.) Spring

• Qinfeng Zhu,
• Beibei Gao,
• Qian Chen,
• Tiantian Luo,
• Guobo Xu and
• Shanggao Liao

Beilstein J. Org. Chem. 2022, 18, 1410–1415, doi:10.3762/bjoc.18.146

• system (1608, 1516, 1490 cm−1). Analysis of its 1H NMR (DMSO-d6) data (Table 1) revealed the presence of two ABX benzene rings [δH 6.92 (d, J = 1.2 Hz, 1H, H-2), 6.83 (d, J = 7.9 Hz, 1H, H-5) and 6.79 (dd, J = 7.9, 1.2 Hz, 1H, H-6); 6.59 (d, J = 1.5 Hz, 1H, H-2′), 6.62 (d, J = 8.0 Hz, 1H, H-5′), and 6.47

• for a benzene, one olefinic carbon, one methylene and two methoxy groups. The above mentioned 1D NMR data of 2 in combination with its molecular formula indicated that the compound must be a symmetrical dimeric benzene derivative. Further analysis of NMR data suggested that the structure of 2 was

Experimental and theoretical studies on the synthesis of 1,4,5-trisubstituted pyrrolidine-2,3-diones

• Nguyen Tran Nguyen,
• Vo Viet Dai,
• Nguyen Ngoc Tri,
• Luc Van Meervelt,
• Nguyen Tien Trung and
• Wim Dehaen

Beilstein J. Org. Chem. 2022, 18, 1140–1153, doi:10.3762/bjoc.18.118

• with CH3NH2 to obtain 2-pyrrolidinone derivative 10ab and its isomers (10ab-v2, 10ab-v3, 10ab-v4) (Figure S7 in Supporting Information File 1). It is clear that the attack of CH3NH2 on the C (C−O) sites to form intermediates (ISs) takes place on the opposite side of the benzene ring (C−C6H5). This is

Facile and diastereoselective arylation of the privileged 1,4-dihydroisoquinolin-3(2H)-one scaffold

• Dmitry Dar’in,
• Grigory Kantin,
• Alexander Bunev and
• Mikhail Krasavin

Beilstein J. Org. Chem. 2022, 18, 1070–1078, doi:10.3762/bjoc.18.109

• spectrum), mass spectrometry and, in the case of compound 10c, by single-crystal X-ray crystallography (Scheme 2). Using compound 10a as the model substrate, we proceeded to screen for suitable reaction conditions that would allow involving this kind of diazo compounds in the TfOH-promoted benzene C

• -arylation reaction (Table 1) [13]. The excess of benzene was varied in the range 10 to 60 equiv and the yield of product 9a was found to improve from 63% to 83% which also allowed lowering the excess of triflic acid to 1.5 equiv. Product 9a was in all cases obtained after only 15 min reaction with high

• mixture of benzene and triflic acid. On the contrary, when adding TfOH to a solution of 10a in benzene, the formation of a complex mixture of unidentifiable products was observed, with only a trace amount of 9a detectable by 1H NMR. The formation of product 9a was unavoidably accompanied by a varying

Electrochemical hydrogenation of enones using a proton-exchange membrane reactor: selectivity and utility

• Koichi Mitsudo,
• Haruka Inoue,
• Yuta Niki,
• Eisuke Sato and
• Seiji Suga

Beilstein J. Org. Chem. 2022, 18, 1055–1061, doi:10.3762/bjoc.18.107

• cyclohexanone such as 3-methylcyclohex-2-en-1-one (1c) gave the desired product 2c selectively in 89% yield (100% selectivity). A benzene-conjugated ketone 1d and an ester 1e could also be subjected to electroreduction to afford the corresponding ketones 2d and 2e in 63% and quantitative yield, respectively

Isolation and biosynthesis of daturamycins from Streptomyces sp. KIB-H1544

• Yin Chen,
• Jinqiu Ren,
• Ruimin Yang,
• Jie Li,
• Sheng-Xiong Huang and
• Yijun Yan

Beilstein J. Org. Chem. 2022, 18, 1009–1016, doi:10.3762/bjoc.18.101

• -4 to C-1, C-2, C-3, C-5, and C-6, from 6-OCH3 to C-6 established a central five-membered carbon ring. Meanwhile, the correlations from H-4 to C-1’, C-1’’, from H-2’ and H-6’ to C-5, and from H-2’’ and H-6’’ to C-3 showed that two benzene rings were conjugated to the central ring at the C-3 and C-5

Electrochemical and spectroscopic properties of twisted dibenzo[g,p]chrysene derivatives

• Tomoya Imai,
• Ryuhei Akasaka,
• Naruhiro Yoshida,
• Toru Amaya and
• Tetsuo Iwasawa

Beilstein J. Org. Chem. 2022, 18, 963–971, doi:10.3762/bjoc.18.96

• , Otsu, Shiga, 520-2194, Japan 10.3762/bjoc.18.96 Abstract Dibenzo[g,p]chrysene (DBC), which consists of a twisted naphthalene core with four fused benzene rings, is a promising framework for organic electronic materials. Therefore, the research for structure–property relationships is important for the

• the benzene ring because of the steric repulsion of substituents on both sides. More specifically, the inductive effect of the MeO group is dominant rather than the mesomeric effect when the substituent is located at both sides of the MeO group. Concerning the torsion of the naphthalene moiety, the

• acenes are an interesting class of compounds due to their characteristic structures and conjugation systems [23][24][25]. Dibenzo[g,p]chrysene (DBC), which consists of a twisted naphthalene core with four fused benzene rings (Figure 1a) [26], is a promising framework for serving as organic semiconductors

Synthetic strategies for the preparation of γ-phostams: 1,2-azaphospholidine 2-oxides and 1,2-azaphospholine 2-oxides

• Jiaxi Xu

Beilstein J. Org. Chem. 2022, 18, 889–915, doi:10.3762/bjoc.18.90

• )phosphine (57) with two atom-equivalents of sulfur in refluxing benzene, affording the zwitterionic 2-aminobenzyl(phenyl)dithiophosphinic acid 58 in 80% yield. It was converted to 2-phenyl-1,3-dihydrobenzo[d][1,2]azaphosphole 2-sulfide (59) in 91% yield by heating at 100–120 °C under vacuum (Scheme 10) [30

Synthesis of novel alkynyl imidazopyridinyl selenides: copper-catalyzed tandem selenation of selenium with 2-arylimidazo[1,2-a]pyridines and terminal alkynes

• Mio Matsumura,
• Kaho Tsukada,
• Kiwa Sugimoto,
• Yuki Murata and
• Shuji Yasuike

Beilstein J. Org. Chem. 2022, 18, 863–871, doi:10.3762/bjoc.18.87

• imidazopyridinyl selenides A Cu-catalyzed cross-coupling reaction using benzene ring substituted diaryl diselenides with terminal alkynes in the presence of bases is effective for synthesizing aryl alkynyl selenides [27][28][29][30][31]. We previously reported a simple method for the synthesis of bis(2-arylimidazo

Post-synthesis from Lewis acid–base interaction: an alternative way to generate light and harvest triplet excitons

• Hengjia Liu and
• Guohua Xie

Beilstein J. Org. Chem. 2022, 18, 825–836, doi:10.3762/bjoc.18.83

• substituents on the benzene rings of B(C6F5)3 is responsible for its stronger Lewis acidity compared to B(C6H5)3, and reacted efficiently with the basic fluorescent materials. In 2011, Hayashi investigated the modification of pyridyl-conjugated polymer films with the Lewis acid BF3 [31]. Through repeated acid