Effects of the aldehyde-derived ring substituent on the properties of two new bioinspired trimethoxybenzoylhydrazones: methyl vs nitro groups

• Dayanne Martins,
• Roberta Lamosa,
• Talis Uelisson da Silva,
• Carolina B. P. Ligiero,
• Sérgio de Paula Machado,
• Daphne S. Cukierman and
• Nicolás A. Rey

Beilstein J. Org. Chem. 2023, 19, 1713–1727, doi:10.3762/bjoc.19.125

• ]. The study also found that those coordination compounds were selective towards abnormal cells, exhibiting lower toxicity for healthy human hepatocytes. On the other hand, an important development in cancer research is the use of physiological metal ion complexes, which afford more biocompatibility and

Tying a knot between crown ethers and porphyrins

• Maksym Matviyishyn and
• Bartosz Szyszko

Beilstein J. Org. Chem. 2023, 19, 1630–1650, doi:10.3762/bjoc.19.120

• alkali metals. Due to the presence of crown ether moieties, the receptors exhibited selective binding of K+, NH4+, and Ba2+. The pronounced changes in the absorption spectra of free-base ligands 1 and TriCP with adding K+, NH4+, and Ba2+ cations were observed, whereas Na+, Mg2+, and Ca2+ did not produce

• applications [43][44][78]. Fullerene-based crown ether-appended porphyrins developed by Diederich and co-workers were used as polymeric material films [79]. Intriguing supramolecular systems capable of electron transfer were developed by D'Souza, Ito and co-workers, showing selective multitopic receptors

• the dipyrrin part of the macrocycle (Figure 4). The introduction of the BF2 moiety into the free-base macrocycles consequently altered the fluorescent properties of the macrocyclic systems. The appended benzo-18-crown-6 in compounds 3a–c was selective for K+, and the macrocycle fluorescence was

Radical chemistry in polymer science: an overview and recent advances

• Zixiao Wang,
• Feichen Cui,
• Yang Sui and
• Jiajun Yan

Beilstein J. Org. Chem. 2023, 19, 1580–1603, doi:10.3762/bjoc.19.116

• overwhelmingly more common in the latter because there are other more selective and efficient solution chemistry methods for post-polymerization modification, such as nucleophilic substitution [94][96]. In this section, we discuss the radical chemistry used in both processes. 3.1 Post-polymerization modification

• of the chemical versatility of the hydroxy moiety (Scheme 15). Site-selective radical C–H activation has been proven to be a useful tool to functionalize relatively inert polymer backbones and upcycling of polymer waste (cf. section 4) [118][119]. Radical chain-end modification as a highly specific

C–H bond functionalization: recent discoveries and future directions

• Indranil Chatterjee

Beilstein J. Org. Chem. 2023, 19, 1568–1569, doi:10.3762/bjoc.19.114

• its combination with organometallic chemistry for site-selective C−H bond functionalization [3][4]. Recent years have witnessed many viable strategies for the synthesis of complex targets utilizing photoredox catalysis, electroorganic catalysis, Lewis acid catalysis, and transition-metal-free

Morpholine-mediated defluorinative cycloaddition of gem-difluoroalkenes and organic azides

• Tzu-Yu Huang,
• Mario Djugovski,
• Sweta Adhikari,
• Destinee L. Manning and
• Sudeshna Roy

Beilstein J. Org. Chem. 2023, 19, 1545–1554, doi:10.3762/bjoc.19.111

• since the selective introduction of substituents at three different positions on the 1,2,3-triazole ring can augment the features of the molecule. Triazoles are also found in many biologically important molecules and functionalized materials [11][12][13][14][15][16]. 1,4,5-Trisubstituted-1,2,3-triazoles

Synthesis of 5-arylidenerhodanines in L-proline-based deep eutectic solvent

• Stéphanie Hesse

Beilstein J. Org. Chem. 2023, 19, 1537–1544, doi:10.3762/bjoc.19.110

• compounds and allow, for example, the formation of rhodanine-fused spiro[pyrrolidine-2,3′-oxindoles] D having antidiabetic activity [6]. Thiazolidinediones and thiazolidinones were found to be potent moieties of a series of furan-2-ylmethylenethiazolidinediones E that were studied as selective ATP

Synthesis and biological evaluation of Argemone mexicana-inspired antimicrobials

• Jessica Villegas,
• Bryce C. Ball,
• Katelyn M. Shouse,
• Caleb W. VanArragon,
• Ashley N. Wasserman,
• Hannah E. Bhakta,
• Allen G. Oliver,
• Danielle A. Orozco-Nunnelly and
• Jeffrey M. Pruet

Beilstein J. Org. Chem. 2023, 19, 1511–1524, doi:10.3762/bjoc.19.108

• markedly less potent towards fungi. Though antifungal properties are desirable, selectivity for prokaryotic over eukaryotic cells would be beneficial for a selective antibacterial treatment. A two-tailed T-test analysis (with significance set at P ≤ 0.05). revealed that these differences in activity for

N-Sulfenylsuccinimide/phthalimide: an alternative sulfenylating reagent in organic transformations

• Fatemeh Doraghi,
• Seyedeh Pegah Aledavoud,
• Mehdi Ghanbarlou,
• Bagher Larijani and
• Mohammad Mahdavi

Beilstein J. Org. Chem. 2023, 19, 1471–1502, doi:10.3762/bjoc.19.106

• thiosulfonates and N-arylthio succinimides.· Suggested mechanism for difunctionalization of alkynyl bromides with thiosulfonates and N-arylthio succinimides. Synthesis of thioesters, acyl disulfides, ketones, and amides by N-thiohydroxy succinimide esters. Proposed mechanism for metal-catalyzed selective

α-(Aminomethyl)acrylates as acceptors in radical–polar crossover 1,4-additions of dialkylzincs: insights into enolate formation and trapping

• Angel Palillero-Cisneros,
• Paola G. Gordillo-Guerra,
• Fernando García-Alvarez,
• Olivier Jackowski,
• Franck Ferreira,
• Fabrice Chemla,
• Joel L. Terán and
• Alejandro Perez-Luna

Beilstein J. Org. Chem. 2023, 19, 1443–1451, doi:10.3762/bjoc.19.103

• 5 and 8a in 77–88% yields, albeit as poorly selective mixtures of diastereoisomers. This lack of stereocontrol is not surprising, given the well-known difficulty to control the relative configuration between the two adjacent stereocenters created during aldol condensations with zinc enolates

Application of N-heterocyclic carbene–Cu(I) complexes as catalysts in organic synthesis: a review

• Nosheen Beig,
• Varsha Goyal and
• Raj K. Bansal

Beilstein J. Org. Chem. 2023, 19, 1408–1442, doi:10.3762/bjoc.19.102

• heteroleptic Cu(I) complexes combining the malonic acid-derived anionic NHC and a neutral imidazol-2-ylidene were also obtained in a very selective manner (Scheme 12). As discussed later, many of these complexes were employed as catalysts. In 2015, Collins et al. [27] compared the stability and reactivity of

• selective method for the synthesis of a wide range of organic compounds [55][56]. Organometallic reagents, such as organolithium, organomagnesium, and organozinc reagents are commonly used in conjugate addition reactions. 2.2.1 Reaction with Grignard reagents: Organomagnesium reagents, such as Grignard

• site-selective NHC–Cu-catalyzed hydroboration of enantiomerically enriched allenes and conversion to the corresponding β-vinyl ketones demonstrates the importance of the strategy. An example is shown below (Scheme 44). 2.2.4 Reaction with organozinc reagents: Organozinc reagents, such as diethylzinc

Functional characterisation of twelve terpene synthases from actinobacteria

• Anuj K. Chhalodia,
• Houchao Xu,
• Georges B. Tabekoueng,
• Binbin Gu,
• Kizerbo A. Taizoumbe,
• Lukas Lauterbach and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2023, 19, 1386–1398, doi:10.3762/bjoc.19.100

• synthase from Allokutzneria albata. The availability of a selective enzyme for allokutznerene is particularly interesting, because the separation of phomopsene and allokutznerene is reportedly very difficult [50]. Last but not least, a sesterterpene synthase for sesterviolene was discovered from

Visible-light-induced nickel-catalyzed α-hydroxytrifluoroethylation of alkyl carboxylic acids: Access to trifluoromethyl alkyl acyloins

• Feng Chen,
• Xiu-Hua Xu,
• Zeng-Hao Chen,
• Yue Chen and
• Feng-Ling Qing

Beilstein J. Org. Chem. 2023, 19, 1372–1378, doi:10.3762/bjoc.19.98

• acyloins (Scheme 1a). Anand’s group [25] demonstrated that a NHC-catalyzed selective acyloin condensation between aromatic aldehydes and trifluoroacetaldehyde ethyl hemiacetal afforded the analogous products (Scheme 1b). In comparison, the synthesis of trifluoromethyl aliphatic acyloins is still

Synthesis of ether lipids: natural compounds and analogues

• Marco Antônio G. B. Gomes,
• Alicia Bauduin,
• Chloé Le Roux,
• Romain Fouinneteau,
• Wilfried Berthe,
• Mathieu Berchel,
• Hélène Couthon and
• Paul-Alain Jaffrès

Beilstein J. Org. Chem. 2023, 19, 1299–1369, doi:10.3762/bjoc.19.96

• whereas heating it in 75% acetic acid solution produced the deprotected compound but migration of the acyl group from the sn-2 to the sn-3 position lead to an inseparable mixture of regioisomers. A selective desilylation of 12.5 was finally achieved with BF3·Et2O producing 12.6 without migration of the

• was selectively alkylated on the primary alcohol to produce 20.2 via the use of dibutyltin oxide as selective reagent for the alkylation of diols [109]. For this reaction, CsF was added to increase the reactivity of the alkyl bromide, likely by a combined effect that includes the interaction of the

Non-noble metal-catalyzed cross-dehydrogenation coupling (CDC) involving ether α-C(sp³)–H to construct C–C bonds

• Hui Yu and
• Feng Xu

Beilstein J. Org. Chem. 2023, 19, 1259–1288, doi:10.3762/bjoc.19.94

• interest in developing novel methodologies in this field of organic chemistry. Keywords: alkylation; cross-dehydrogenation coupling; ether; non-noble metals; Introduction Since the 1970s, organic chemists have developed many selective cross-coupling methods for the construction of C–C bonds, such as the

• indoles with 1,4-dioxane C(sp3)–H bonds via Ni(II) catalysis (Scheme 35) [100]. The selectivity of the reaction is determined by the catalyst used, which provides an efficient strategy for the selective construction of cyclic ethers containing heteroaromatic structures. Huang et al. reported a highly

Selective construction of dispiro[indoline-3,2'-quinoline-3',3''-indoline] and dispiro[indoline-3,2'-pyrrole-3',3''-indoline] via three-component reaction

• Ziying Xiao,
• Fengshun Xu,
• Jing Sun and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2023, 19, 1234–1242, doi:10.3762/bjoc.19.91

• . This reaction provided efficient synthetic protocols for the synthesis of dispiro[indoline-3,2'-quinoline-3',3''-indoline] and dispiro[indoline-3,2'-pyrrole-3',3''-indoline] derivatives. A plausible reaction mechanism was proposed to explain the selective formation of the different polycyclic compounds

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

• ; photocatalysis; radicals; Introduction The behavior of alkyl radicals has been studied rigorously for decades, though only recently have these come to be widely viewed as selective and useful synthetic intermediates [1][2][3][4]. This sea change has been driven by innovations in both the generation and

• behavior of P450 oxygenases encouraged early work on site-selective C–H functionalization [20]. Throughout their studies, it was found that manganese could perform the same HAT and RLT steps as iron at heme active sites. Groves developed the manganese tetramesitylporphine catalyst V (Scheme 2), which was

• adventitious discovery of nitrate functioning as a mild and selective oxidant in RLT catalytic systems presents many opportunities for future method development and are avidly pursuing this area of research. Outlook After scant exploration following its elucidation in early mechanistic studies of bioinorganic

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

• was first reported in 2010 [133], the subsequent collection of works by Vasdev and Liang led to an improved methodology appropriate for the time and temperature requirements of radiofluorination reactions, and led to a mechanistic proposal dependent on σ-hole selective halogen bonding [134]. Vasdev

Selective and scalable oxygenation of heteroatoms using the elements of nature: air, water, and light

• Damiano Diprima,
• Hannes Gemoets,
• Stefano Bonciolini and
• Koen Van Aken

Beilstein J. Org. Chem. 2023, 19, 1146–1154, doi:10.3762/bjoc.19.82

• of heteroatoms, making them a promising alternative to traditional oxidants in the chemical industry [9]. Our interest in sustainable oxidation methodologies led us to study the selective oxidation of various heteroatoms to their corresponding oxides, including sulfides to sulfoxides, phosphine to

• emerged [26], but they suffer from low selectivity or long reaction times [27][28], making them unsuitable for large-scale industrial production. In this study (Scheme 1C), we introduce a photochemical, catalyst-free oxidation method for heteroatoms that is highly selective and suitable for industrial

• negligible depending on the concentration of water. Conclusion A catalyst-free methodology for the selective oxygenation of heteroatoms (S, P, Se) has been developed using only air, water, and light. The protocol allows high conversion and excellent selectivity for a wide scope of substrates, with relative

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

• (PEC). Herein, we review the most recent contributions to these fields in both oxidative and reductive activations of organic functional groups. New opportunities for organic chemists are captured, such as selective reactions employing super-oxidants and super-reductants to engage unactivated chemical

• photoredox catalysts and ii) energy that parallels the energy of UV-driven transformations, but under cheaper, safer conditions and in a more selective manner by indirect substrate activation via a catalyst. These are: a) multi-photon processes that accumulate visible light photon energies for electron

• -Tribromopyrimidine (6a), whose core pyrimidine structure can be found in many biologically active compounds, could be sequentially substituted with 1,3,5-trimethoxybenzene and N-methylpyrrole to give 8a. The protocol also enabled the selective reductive dehalogenation at the benzylic position of 9a with green light

Synthesis of imidazo[4,5-e][1,3]thiazino[2,3-c][1,2,4]triazines via a base-induced rearrangement of functionalized imidazo[4,5-e]thiazolo[2,3-c][1,2,4]triazines

• Dmitry B. Vinogradov,
• Alexei N. Izmest’ev,
• Angelina N. Kravchenko,
• Yuri A. Strelenko and
• Galina A. Gazieva

Beilstein J. Org. Chem. 2023, 19, 1047–1054, doi:10.3762/bjoc.19.80

• varied. Increasing the amount of KOH and reaction time led to an increase in the yield of the potassium salts 3a,b even at room temperature. It was found that stirring esters 1a–i in methanol in the presence of 2.5 equivalents of an aqueous solution of KOH provided selective formation of imidazo[4,5-e

• ). Conclusion In summary, routes for the selective formation of various derivatives of the new heterocyclic system, imidazo[4,5-e][1,3]thiazino[2,3-c][1,2,4]triazine, were found during the cascade processes of alkaline hydrolysis of the ester group in functionalized derivatives of imidazo[4,5-e]thiazolo[3,2-b

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

• (BBs) [1][2]. Iterative cycles of glycosylation, capping, and selective deprotection afford the support-bound glycan with a programmable sequence (Figure 1A). The protected glycan is then cleaved from the solid support and subjected to post-AGA deprotection steps to reveal the target glycan. AGA is

Synthesis of tetrahydrofuro[3,2-c]pyridines via Pictet–Spengler reaction

• Elena Y. Mendogralo and
• Maxim G. Uchuskin

Beilstein J. Org. Chem. 2023, 19, 991–997, doi:10.3762/bjoc.19.74

• relatively selective α2-adrenoceptor antagonist [5]. Despite the simplicity of the tetrahydrofuro[3,2-c]pyridine core, only limited approaches for the synthesis of this subclass of heterocycles using furan derivatives as starting compounds have been described [6][7][8]. The first group of methods is based on

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

• -bonding interactions to facilitate a highly face-selective nucleophilic attack by π-nucleophile to the cyclic imine (see transition state 22’ in Scheme 7a). The BINOL-derived chiral phosphoric acid P8 was employed as the asymmetric organocatalyst for this transformation to construct the heterodimerized

• presence of an electron-donating functional group is crucial in the ring to activate it for aromatic electrophilic substitution processes. In 2019, Zhang and co-workers succeeded in the C6-selective aminoalkylation of 2,3-disubstituted indoles 4 without the presence of a directing group in the benzene ring

• congested reactants (Scheme 15b) [41]. Very recently, Akiyama and co-workers demonstrated a C2-selective aza-Friedel–Crafts reaction of unmodified pyrroles 9 with (alkynyl)(trifluoromethyl)imines 57 catalyzed by the chiral phosphoric acid P17. This reaction produced an aza-quaternary stereocenter bearing 2

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

• 2.5 mol % HPA/SiO2 as catalyst, solventless under MW irradiation. The main advantages of this protocol is its greener, eco-friendly, stable and reusable heterogeneous catalyst, smooth and selective reaction under solvent-free conditions, excellent yields of products, easy work-up and simple handling

Photoredox catalysis enabling decarboxylative radical cyclization of γ,γ-dimethylallyltryptophan (DMAT) derivatives: formal synthesis of 6,7-secoagroclavine

• Alessio Regni,
• Francesca Bartoccini and
• Giovanni Piersanti

Beilstein J. Org. Chem. 2023, 19, 918–927, doi:10.3762/bjoc.19.70

• selectively targeted by photoredox catalysis to enable unprecedented modification of the amino acid. In this context, it is worth mentioning that the single-electron oxidation of the indole moiety in tryptophan provides the radical cation, which enables selective C-radical generation at the weaker benzylic

• )PF6 (E1/2*III/II = +1.21 V, E1/2III/II = −1.37; E1/2IV/*III = −0.89, E1/2 IV/III = +1.69 V) [74] would permit efficient radical generation and C(sp3)–C(sp3) bond formation either by challenging selective radical–radical cross-coupling or by radical addition to a π-bond, enabling a rare example of

• diene [90][91]. In addition, these results support the hypothesis that the decarboxylative cyclization can occur through subsequent selective 6-exo-trig radical addition. It also has been reported that it is difficult to detect which intermediate is really involved, since they are easily