Metal catalyst-free N-allylation/alkylation of imidazole and benzimidazole with Morita–Baylis–Hillman (MBH) alcohols and acetates

• Olfa Mhasni,
• Jalloul Bouajila and
• Farhat Rezgui

Beilstein J. Org. Chem. 2023, 19, 1251–1258, doi:10.3762/bjoc.19.93

• , such alcohols were in situ converted into the corresponding O-allyl carbamates as leaving groups, followed by their reaction with imidazoles, affording the SN2’ products 3 (Scheme 1, reaction 1, iii). Correlatively, we have previously reported a direct amination of cyclic MBH alcohols 4 with morpholine

Radical ligand transfer: a general strategy for radical functionalization

• David T. Nemoto Jr,
• Kang-Jie Bian,
• Shih-Chieh Kao and
• Julian G. West

Beilstein J. Org. Chem. 2023, 19, 1225–1233, doi:10.3762/bjoc.19.90

• the mechanism. In 2015, the Groves group reported their manganese porphin-based catalyst V and related species being capable of participating in decarboxylation reactions (Scheme 4) [42]. The activated Mn(V) species is proposed to perform HAT carboxylic acid O–H bond, directly forming a carboxyl

Cyanothioacetamides as a synthetic platform for the synthesis of aminopyrazole derivatives

• Valeriy O. Filimonov,
• Alexandra I. Topchiy,
• Vladimir G. Ilkin,
• Tetyana V. Beryozkina and
• Vasiliy A. Bakulev

Beilstein J. Org. Chem. 2023, 19, 1191–1197, doi:10.3762/bjoc.19.87

• Valeriy O. Filimonov Alexandra I. Topchiy Vladimir G. Ilkin Tetyana V. Beryozkina Vasiliy A. Bakulev Technology of Organic Synthesis Department, Ural Federal University named after the first President of Russia B. N. Yeltsin, 19 Mira st. Yekaterinburg 620002, Russia Department of Organic Chemistry

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

• effective as metallocarbene precursors, the o-anisyl derivative 39 gave an improved 90% yield of 65, compared to the 80% yield achieved with ylide 31 under identical reaction conditions. Zhdankin also assessed the cyclopropenation of phenylacetylene, in which 39 gave 66 in 68% yield, which was again a

• ). The authors’ explanation for the improved reactivity of o-anisyl derivative 39 was based on its improved solubility in dichloromethane. The contact distances were both within the Van der Waals radii criteria for confirming non-covalent interactions [33], which likely contributed to the ylide’s

Two new lanostanoid glycosides isolated from a Kenyan polypore Fomitopsis carnea

• Winnie Chemutai Sum,
• Sherif S. Ebada,
• Didsanutda Gonkhom,
• Cony Decock,
• Rémy Bertrand Teponno,
• Josphat Clement Matasyoh and
• Marc Stadler

Beilstein J. Org. Chem. 2023, 19, 1161–1169, doi:10.3762/bjoc.19.84

• ’ Universite Catholique de Louvain (BCCM/MUCL), Place Croix du Sud 3, B-1348 Louvain-la-Neuve, Belgium Department of Chemistry, Faculty of Science, University of Dschang, P. O. Box 67, Dschang, Cameroon Department of Chemistry, Egerton University, P.O. Box 536, 20115, Njoro, Kenya 10.3762/bjoc.19.84 Abstract

• Chemical exploration of solid-state cultures of the polypore Fomitopsis carnea afforded two new C31 lanostane-type triterpenoid glycosides, forpiniosides B (1) and C (2) together with two known derivatives, namely 3-epipachymic acid (3) and (3α,25S)-3-O-malonyl-23-oxolanost-8,24(31)-dien-26-oic acid (4

• elucidation of two new C31 lanostane-type triterpenoid glycosides (compounds 1 and 2 in Figure 1) together with two known derivatives, namely 3-epipachymic acid (3α-acetoxy-16α-hydroxy-5α-lanost-8,24(31)-dien-21-oic acid (3)) [24] and (3α,25S)-3-O-malonyl-23-oxolanost-8,24(31)-dien-26-oic acid (4) [25

Photoredox catalysis harvesting multiple photon or electrochemical energies

• Mattia Lepori,
• Simon Schmid and
• Joshua P. Barham

Beilstein J. Org. Chem. 2023, 19, 1055–1145, doi:10.3762/bjoc.19.81

The effect of dark states on the intersystem crossing and thermally activated delayed fluorescence of naphthalimide-phenothiazine dyads

• Liyuan Cao,
• Xi Liu,
• Xue Zhang,
• Jianzhang Zhao,
• Fabiao Yu and
• Yan Wan

Beilstein J. Org. Chem. 2023, 19, 1028–1046, doi:10.3762/bjoc.19.79

• substituents on the NI unit (NI-PTZ-F, NI-PTZ-Ph, NI-PTZ-CH3, NI-PTZ-OCH3), and the electron-donating ability of the PTZ unit was modified by oxidation of the sulfur atom to the sulfoxide (NI-PTZ-F-O, NI-PTZ-Ph-O, NI-PTZ-C5-O). The advantage of the oxidation approach is that almost only the energy of the 1CS

• unit (Figure 2e and 2f) [57]. Moreover, it is noted that the CS emission wavelength of NI-PTZ-F-O and NI-PTZ-Ph-O is different from a 4-diphenylamino-substituted NI [58]. These results indicate that the 1CS state of these two dyads involves the oxidized PTZ unit as a whole electron donor, not only the

• N atom of the PTZ unit [59][60]. Further, the NI-PTZ-F-O and NI-PTZ-Ph-O compounds adopt an orthogonal geometry, and the N atom in the PTZ unit is not in π-conjugation with NI moiety due to a conformational restriction [55]. Thus, it is not the ordinary intramolecular charge transfer (ICT) state

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

• stoichioimetry and that a number of simple and modified cyclodextrins bind CO2 in water with a Kg of 0.18–1.2 bar−1 (7–35 M−1) with per-O-methyl α-cyclodextrin having the highest CO2 affinity. Keywords: carbon dioxide; crystals; cyclodextrin; gas binding; Introduction The concentration of carbon dioxide (CO2

• split over two positions yielding in total 5.75 mol of water per CO2. The hydration is similar to that of native α-CD [13] and that of the krypton inclusion complex which has 5.28 water/Kr [14]. The CO2 molecule refines with an optimal occupancy of 0.84 and linear geometry (178.2(6)o) with C–O bond

• characteristic water absorption at 3200–3600 cm−1 and the C=O band of CO2 at 2350 cm−1 during the both weigth losses but mainly CO2 at the first lump and predominantly water at the second loss. This also suggest a comparatively weak binding of the CO2. We determined the binding constant for CO2 to cyclodextrins

Linker, loading, and reaction scale influence automated glycan assembly

• Marlene C. S. Dal Colle,
• Manuel G. Ricardo,
• Nives Hribernik,
• José Danglad-Flores,
• Peter H. Seeberger and
• Martina Delbianco

Beilstein J. Org. Chem. 2023, 19, 1015–1020, doi:10.3762/bjoc.19.77

• ] and L2 [3] are based on the o-nitrobenzyl scaffold [23][24] and expose a hydroxy group that serves as glycosyl acceptor in the first AGA cycle (Figure 1B). While L1 displays a flexible aliphatic chain terminating with a primary alcohol, L2 carries a secondary benzylic alcohol. Upon irradiation with UV

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

• primary arylamines 1, bearing electron-donating as well as electron-withdrawing groups on the aromatic ring. The results are shown in Scheme 2. The reaction of o-toluidine and p-toluidine with ylide 2a resulted in products 3b and 3c with 77% and 81% yields. Next, the electron-rich arylamines o-anisidine

• and p-anisidine reacted efficiently with iodonium ylide 2a under standard conditions to give products 3d and 3e with excellent yields. Further, the treatment of arylamines containing electron-withdrawing groups such as p-NO2, m-NO2, and o-CO2Et with ylide 2a delivered the corresponding diarylamines 3f

• –h in 57–65% yields. Also, the halogen-substituted arylamines such as p-bromo, o-bromo, p-chloro, and p-fluoroanilines reacted smoothly to produce the corresponding diarylamine products 3i–l with 65–73% yields. To identify the effect of steric hindrance we treated 2,6-dimethylaniline under optimal

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

• for developing the scope of the reaction and the results are summarized in Table 2. It can be seen that all reactions gave the desired isoquinolino[1,2-f][1,6]naphthyridine derivatives 4a–o in good to excellent yields. Isoquinoline itself and its 4-, 5-, and 6-bromo-substituted derivatives were

• -dihydropyridines derived from the condensation of acetylacetone also afforded the expected product 4o in 65% yield. The chemical structures of the obtained isoquinoline[2,1-h][1,7]naphthyridines 4a–o were fully characterized by various spectroscopy methods and further confirmed by determination of the single

• [4.2.0]octa-3,7-dienes 5a–o could be successfully obtained in moderate to good yields by carrying out the reaction of dimethyl acetylenedicarboxylate and 5,6-unsubstituted 1,4-dihydropyridines in refluxing acetonitrile for three hours (Table 3). As can be seen, unsymmetric 1,4-dihydropyridines with N–Bn

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

• -naphthofuran or benzofuran analogues. The achiral phosphoric acid (PhO)2P(O)OH was the catalytic reagent to execute the process delivering the products with low to moderate chemical yields. Attempts to make the process stereoselective, a series of chiral phosphoric acid catalysts were screened in the model

• 2019, Inokuma, Yamada and co-workers reported the C3–H bond functionalization of indoles 4 through aza-Friedel–Crafts reaction utilizing N-o-nitrophenylsulfenyl (Nps)-iminophosphonates 32 as electrophiles. The chiral phosphoric acid P11 was used as H-bonding catalyst to impart stereoselectivities into

• necessary as it is engaged in the H-bonding interaction with the catalyst P=O moiety whereas the imine nitrogen of 69 accepts an H-bond from the catalyst OH group (see transition state 103). These dual noncovalent interactions were the reason behind a highly face-selective attack by the ortho-carbon of the

Clauson–Kaas pyrrole synthesis using diverse catalysts: a transition from conventional to greener approach

• Dileep Kumar Singh and
• Rajesh Kumar

Beilstein J. Org. Chem. 2023, 19, 928–955, doi:10.3762/bjoc.19.71

• aniline having electron withdrawing and electron donating substituents on the aromatic ring. However, this protocol did not produce a product with aliphatic amines and satirically hindered o-substituted anilines. A plausible mechanism for the formation of N-arylpyrroles is depicted in Scheme 18b. In 2014

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

• the construction of a range of δ-olefin-containing aliphatic nitriles with (E)-configuration selectivity. This new method features wide substrate scope, mild conditions, and direct N–O activation. Keywords: direct N–O activation; E-selectivity; nitrile synthesis; ring-opening cross-coupling; sulfuryl

• ) carbon, which leads to side reactions of the alkyl intermediates [14][19][20]. Besides, most of the C(sp2)–C(sp3) reactions employ organic halides or organometallic reagents [21][22][23], which are not environmentally friendly. Recently, based on the activation effect of O-acyloximes on N–O bonds [24][25

• works, we contemplated that the N–O bond of cyclobutanone oxime derivatives could be activated by SO2F2 in situ to enable cleavage of the C–C bond, which could achieve this transformation without going through inefficient pre-introduction of electrophores. Herein, we describe how this concept has been

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

• -dicarbonyl compounds are treated with (diacetoxyiodo)benzene and tetrabutylammonium iodide, iodination occurs at the α-position of the nitro group, and the subsequent O-attack of the enol moiety leads to 2,3-dihydrofuran. Cyclopropane was successfully synthesized through C-attack as the acyl group became

• the enol form, a C-attack (path a) furnishes cyclopropane 1, and an O-attack (path b) furnishes dihydrofuran 8. When the R1 group becomes bulkier, the hydroxy group may be far from the reaction site because of the steric repulsion in the stable conformation. Another possibility is that the bulky

• addition of the 1,3-dicarbonyl compound 3 to nitrostyrene 2 and the α-iodination of the adduct 4, two cyclization modes became possible owing to the ambident property of enol 12. Dihydrofuran 8 was formed in the case of an O-attack, and nitrocyclopropane 1 was formed in the case of a C-attack. Furthermore

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

• pyridines by C–H addition to olefins under cationic half-sandwich rare-earth catalysis [50]. They carried out the reaction in the presence of dialkyl complexes of scandium (Sc) or yttrium (Y) such as (C5Me5)Ln(CH2C6H4NMe2-o)2 (Ln = Sc, Y) in combination with B(C6F5)3 as an activator. The method demonstrated

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

• lactams 1, 2b, and 3 (i.e., cleavage of Ar–N bond or removal of >C(CH3)2 or >C=O bridge) leads to secondary α-bromo(phenyl)acetamides 4a and 4b. When α-bromoamide 4a was treated with thiobenzamide without any base (entries 1 and 7 in Table 3), 2,5-diphenyl-1,3-thiazol-4-ol (13) was the only product

• ) with activation free energies 47 and 59 kJ·mol−1 than from 4-bromo-1,1-dimethyl-1,4-dihydroisoquinolin-3(2H)-one (2b) and N-phenyl-2-bromo(phenyl)acetamide (4a) with activation free energies 78 and 88 kJ·mol−1. These trends fully correspond to a combination of electronic effects (bridging C=O has an

Facile access to 3-sulfonylquinolines via Knoevenagel condensation/aza-Wittig reaction cascade involving ortho-azidobenzaldehydes and β-ketosulfonamides and sulfones

• Ksenia Malkova,
• Andrey Bubyrev,
• Stanislav Kalinin and
• Dmitry Dar’in

Beilstein J. Org. Chem. 2023, 19, 800–807, doi:10.3762/bjoc.19.60

• have developed a new convenient protocol for the synthesis of 3-sulfonyl-substituted quinolines (sulfonamides and sulfones). The approach is based on a Knoevenagel condensation/aza-Wittig reaction cascade involving o-azidobenzaldehydes and ketosulfonamides or ketosulfones as key building blocks. The

• . While the ortho-amino carbonyl reagents are not always easily accessible and sometimes unstable (e.g., aminoaldehydes), both o-azidoaldehydes [58][59][60][61][62][63][64][65] and o-azidoketones [66][67][68][69] have been proved to be appropriate substrates for quinoline derivatives synthesis. Recently

• , the method for the synthesis of 3-acyl-substituted quinolines from o-azidobenzaldehydes and 1,3-dicarbonyl compounds was reported [70][71] (Figure 2a). A combination of Knoevenagel condensation and aza-Wittig reaction allowed to build up target products in high yields. In case of [70], the procedure

Non-peptide compounds from Kronopolites svenhedini (Verhoeff) and their antitumor and iNOS inhibitory activities

• Yuan-Nan Yuan,
• Jin-Qiang Li,
• Hong-Bin Fang,
• Shao-Jun Xing,
• Yong-Ming Yan and
• Yong-Xian Cheng

Beilstein J. Org. Chem. 2023, 19, 789–799, doi:10.3762/bjoc.19.59

• (1), kronopoiols A (2) and B (3), 5-O-methyldaphnegiralin C1 (4), and kronoponoids A (7) and B (8). Biological activity experiments were conducted with the isolated compounds, revealing that compounds 3–5 exhibited the expression of iNOS in a dose-dependent manner. Results and Discussion Structural

• attributable to two methyl groups, two methoxy carbons, one methylene, three methines (one sp2 and one of them oxygenated), one ketone, and five sp2 carbons (two of them oxygenated). Some of these signals resemble those of 8-O-methylteratosphaerone B [17], suggesting compound 1 being an analogue, but with an

• that the second benzene ring shares the same structure. By comparing the 1H and 13C chemical shifts with similar compounds [19][20][21][22], the NMR data implied the presence of C-8a–C-9–C-9a and C-4a–O–C-10a bonds in the structure of 2. Consequently, the structure of compound 2 was identified and

Sulfate radical anion-induced benzylic oxidation of N-(arylsulfonyl)benzylamines to N-arylsulfonylimines

• Joydev K. Laha,
• Pankaj Gupta and
• Amitava Hazra

Beilstein J. Org. Chem. 2023, 19, 771–777, doi:10.3762/bjoc.19.57

• of the intermediate product 2c and 2-aminobenzamide gave 2-(p-tolyl)quinazolin-4(3H)-one (4b) in 85% yield. Furthermore, when various other ortho-substituted aniline derivatives such as 2-aminobenzylamine, 2-aminothiophenol, and o-phenylenediamine are reacted with imine 2a in a similar manner, the

Palladium-catalyzed enantioselective three-component synthesis of α-arylglycine derivatives from glyoxylic acid, sulfonamides and aryltrifluoroborates

• Bastian Jakob,
• Nico Schneider,
• Luca Gengenbach and
• Georg Manolikakes

Beilstein J. Org. Chem. 2023, 19, 719–726, doi:10.3762/bjoc.19.52

• structural motif in vancomycin, teicoplanin, feglymycin, and amoxicillin. Therefore, the OBn-protected aryltrifluoroborate was subjected to our standard reaction conditions, affording the desired N,O-protected (S)-arylglycine derivative 10k in 38% yield and an enantiomeric ratio of 88:12. By employing the

Strategies in the synthesis of dibenzo[b,f]heteropines

• David I. H. Maier,
• Barend C. B. Bezuidenhoudt and
• Charlene Marais

Beilstein J. Org. Chem. 2023, 19, 700–718, doi:10.3762/bjoc.19.51

• heteroatoms (e.g., O, N, S, P, B and Si) in the heterocyclic ring result in analogues of dibenzo[b,f]azepines and -oxepines. This group of compounds will thus be broadly referred to as dibenzo[b,f]heteropines (1). The first section of this review will cover the synthesis of dibenzo[b,f]heteropines (1) and

• the incorporation of a diverse scope of heteroatoms (e.g., O, N, S, P, B and Si) and may give access to a range of dibenzo[b,f]heteropines 1 using common intermediates [30][31]. Therefore, this section will be broadly organised by reaction type responsible for ring closure. Review 1 Industrial route

• of o-nitrotoluene (22) Reduction to 2,2'-diaminobibenzyl (20) Ring-closing via amine condensation Catalytic dehydrogenation 1.1 Oxidative coupling of o-nitrotoluene (22) and reduction to 2,2'-diaminobibenzyl (20) The preparation of dinitrobibenzyl (21) can be achieved by the oxidative coupling of

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

• of C–C, C–O, P–C, and P–O bonds in the rings, while annulations are composed of [5 + 2], [6 + 1], and [7 + 1] fashions for the formation of the rings (Figure 2). This review includes the synthesis of seven to fourteen-membered phostam, phostone, and phostine derivatives. Aboundant methods have been

• developed for the synthesis of seven-membered phostone and phostine derivatives. Review 1 Synthesis via cyclizations Cyclizations are major strategies for the construction of medium and large phostams, phostones, and phostines via C–C, C–O, P–C, and P–O bond formations, respectively. These strategies can be

Photocatalytic sequential C–H functionalization expediting acetoxymalonylation of imidazo heterocycles

• Deepak Singh,
• Shyamal Pramanik and
• Soumitra Maity

Beilstein J. Org. Chem. 2023, 19, 666–673, doi:10.3762/bjoc.19.48

• the aryl ring – as electron-releasing groups (Me, OMe) showed little more reactivity than electron-withdrawing groups (CN) at the same position (4b, 4f, and 4g). Halogen-substituted IPs also followed the general reactivity trend of the respective halogens (4c–e). Excellent reactivity was found for o-F

Nucleophile-induced ring contraction in pyrrolo[2,1-c][1,4]benzothiazines: access to pyrrolo[2,1-b][1,3]benzothiazoles

• Ekaterina A. Lystsova,
• Maksim V. Dmitriev,
• Andrey N. Maslivets and
• Ekaterina E. Khramtsova

Beilstein J. Org. Chem. 2023, 19, 646–657, doi:10.3762/bjoc.19.46

• ] and reactions of 3-acyl-2,3-dihydro-1,3-benzothiazole-2-carbonitriles with acetylenedicarboxylate (Scheme 1, entry 9) [4]. The second group of approaches to the PBTA scaffold is an annulation of o-aminothiophenol with a pyrrolothiazole moiety (Scheme 2). It includes catalytic cascade reactions of o

• -aminothiophenol with donor–acceptor cyclopropanes (Scheme 2, entry 10) [27], condensations of o-aminothiophenol with 4-oxo acids or their derivatives (Scheme 2, entry 11) [2][28][29][30][31] and cascade reactions of o-aminothiophenol, furfural and anhydrides of 2,3-unsaturated carboxylic acids (Scheme 2, entry 12

• irradiation [49]. Secondly, the presence of a highly reactive thioester group C4=O [50] in FPDs 1 made us to expect the position C4 (Figure 2) to be the most reactive electrophilic center in these molecules, which would also contribute to the development of a new synthetic approach to PBTAs. We started our