Hetero-polycyclic aromatic systems: A data-driven investigation of structure–property relationships

• Sabyasachi Chakraborty,
• Eduardo Mayo Yanes and
• Renana Gershoni-Poranne

Beilstein J. Org. Chem. 2024, 20, 1817–1830, doi:10.3762/bjoc.20.160

• , and because some of them contain more than one heteroatom, this resulted in an unequal distribution of the heteroatoms themselves. Thus, due to the design of the dataset construction, the relative prevalence is approximately 6:4:1:1 for B:N:O:S. COMPAS-2 comprises two datasets – COMPAS-2x and COMPAS

• S atoms appear to be more evenly distributed over the property space, however, certain areas can be identified with slightly higher populations of heteroatom-rich PASs. To explore this further, we divided each property into ten evenly spaced sections and binned all the molecules in each respective

• blocks in each bin is equal to 1. The size of each block represents the likelihood of a heteroatom from this bin being a certain type. As we noted in the Data section, the total numbers of heteroatoms are not equal (the ratios of B:N:O:S atoms are approximately 6:4:1:1). Therefore, each block was

Tetrabutylammonium iodide-catalyzed oxidative α-azidation of β-ketocarbonyl compounds using sodium azide

• Christopher Mairhofer,
• David Naderer and
• Mario Waser

Beilstein J. Org. Chem. 2024, 20, 1510–1517, doi:10.3762/bjoc.20.135

• conditions are best-suited. We have recently established the use of dibenzoyl peroxide (DBPO) as a very powerful oxidant for oxidative heterofunctionalization reactions using simple nucleophilic inorganic salts as heteroatom transfer reagents [39][41]. This was successfully demonstrated for the non-catalyzed

Towards an asymmetric β-selective addition of azlactones to allenoates

• Behzad Nasiri,
• Ghaffar Pasdar,
• Paul Zebrowski,
• Katharina Röser,
• David Naderer and
• Mario Waser

Beilstein J. Org. Chem. 2024, 20, 1504–1509, doi:10.3762/bjoc.20.134

• -functionalizations by reacting them with suited C- or heteroatom electrophiles. α-Amino acid-derived azlactones 1 are amongst the most commonly utilized starting materials to access more diverse chiral α,α-disubstituted amino acids (Scheme 1A) [20][21][22]. More specifically, these compounds can be engaged in a

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

• been known as indispensable building blocks in modern organic chemistry. Many isocyanide-based carbon–carbon and carbon–heteroatom bond forming reactions have been developed in fascinating ways over the past decades [4][5][6]. The famous multicomponent reactions such as Passerini reaction, Ugi reaction

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

• and alkyl radicals, has shown great promise in the synthesis and functionalization of various organic molecules [15][16]. These carbon radicals can be generated in several ways. The first and most straightforward method is the homolytic cleavage of labile C–heteroatom bonds, especially alkyl halides

• , C–C, and C–heteroatom bond formations. The best known technique for the creation of alkyl radicals is the homolytic cleavage of the C–X bond of alkyl halides by toxic tin hydride [17]. Later, various efforts have been made to replace toxic tin hydrides with other reagents [33][34][35][36][37][38][39

• , heteroatom-substituted alkenes, and conjugated alkenes. Using alkyl oxalates obtained from readily available alcohols facilitated the construction of intricate alkyl compounds. However, only tertiary alkyl oxalates were applicable to this methodology. In 2019, Studer et al. [49] reported photoinduced C–O

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

• such as heteroatom doping and porous defects for unique properties and functions. For instance, with nitrogen atoms as dopants [1][2][3], a range of applications, such as electrocatalysis [4] and gas storage [5], has been exploited. Although the locations of nitrogen, in addition to the types

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

• -311++G** method for the TS geometry obtained using CI-NEB and Gaussian16 is shown by histograms in Figure 2c. These TBR barriers calculated using both methods are also provided in Table 1. It is clear from Figure 2c that the TBR barrier solely depends on the type of heteroatom unit used to extend the

• an undesired byproduct due to thermal dissociation. Consequently, the type-Id switch does not meet the criteria for reversible photoswitching desired for an ideal MOST system. This leads to the inference that the heteroatom used to extend the unsaturated bridge of the BBD molecules plays a crucial

Three-component N-alkenylation of azoles with alkynes and iodine(III) electrophile: synthesis of multisubstituted N-vinylazoles

• Jun Kikuchi,
• Roi Nakajima and
• Naohiko Yoshikai

Beilstein J. Org. Chem. 2024, 20, 891–897, doi:10.3762/bjoc.20.79

• difunctionalization of alkynes with various heteroatom and carbon nucleophiles [27][28][29][30][31][32][33][34]. Specifically, intermolecular trans-iodo(III)functionalization of alkynes has been achieved using oxygen nucleophiles such as alcohols [28][32], ethers [33], carboxylic acids [31], phosphate esters [31

• other heteroatom nucleophiles is currently underway. Synthesis of N-vinylazoles. Scope of three-component N-alkenylation of azoles. Competition experiments and plausible reaction pathway. Preparative-scale reaction and product transformations. Reaction conditions: (a) Pd(PPh3)4, 4-MeOC6H4B(OH)2, Cs2CO3

Green and sustainable approaches for the Friedel–Crafts reaction between aldehydes and indoles

• Periklis X. Kolagkis,
• Eirini M. Galathri and
• Christoforos G. Kokotos

Beilstein J. Org. Chem. 2024, 20, 379–426, doi:10.3762/bjoc.20.36

• . The difference between the two mechanistic pathways is the nature of activation of the carbonyl group. Protic acids induce the protonation of the carbonyl group of the aldehyde or ketone, enhancing its electrophilic character. Whereas, Lewis acid catalysts bind to the heteroatom of the carbonyl group

Mechanisms for radical reactions initiating from N-hydroxyphthalimide esters

• Carlos R. Azpilcueta-Nicolas and
• Jean-Philip Lumb

Beilstein J. Org. Chem. 2024, 20, 346–378, doi:10.3762/bjoc.20.35

• absorption spectra of PTH1 was observed, suggesting the formation of a charge transfer complex of the type 88 [68] (Scheme 17A). tert-Butyl radical (64), along with additional 2° and 3° alkyl radicals, resulting from these EDA complexes were harnessed in C(sp3)-heteroatom bond forming reactions [69], and in

• the three-component alkylacylation of olefins [108]. Alternatively, NHC catalysts can mediate the generation of radical intermediates from NHPI esters via the stabilization of a photoactive EDA complex. In 2020, Wang and Chen reported a photochemical C(sp3)-heteroatom coupling reaction of NHPI esters

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

• heteroatom-based counterparts, have attracted the attention of the scientific community for two centuries already. Initially, major interest resulted from their structural, optical and electronic properties at the molecular level, but the last decades witnessed the rise of molecular materials and π

• , this class of compounds is prone to valence isomerization via 6π-electrocyclization leading to the formation of heteroatom-containing norcaradiene, and oxepine has been shown to exist in equilibrium with its valence isomer benzene oxide [37]. In contrast with the parent oxepine, which is isolable at

• the synthesis of a series of HBC precursors incorporating a group-16 heteroatom embedded in a seven-membered ring. In the case of oxygen, the fully cyclized HBC 26a containing an oxepine ring and exhibiting a saddle-shape tridimensional structure was successfully prepared (Scheme 8, top). Conversely

Facile access to pyridinium-based bent aromatic amphiphiles: nonionic surface modification of nanocarbons in water

• Lorenzo Catti,
• Shinji Aoyama and
• Michito Yoshizawa

Beilstein J. Org. Chem. 2024, 20, 32–40, doi:10.3762/bjoc.20.5

• PA-OCH3 to solubilize not only conventional nanocarbons but also heteroatom-containing ones. To obtain direct structural information of the encircled (g-C3N4)m, dry-state AFM measurements (on mica) were conducted using an aqueous solution of (PA-OCH3)n·(g-C3N4)m. The obtained AFM images showed large

Recent advancements in iodide/phosphine-mediated photoredox radical reactions

• Tinglan Liu,
• Yu Zhou,
• Junhong Tang and
• Chengming Wang

Beilstein J. Org. Chem. 2023, 19, 1785–1803, doi:10.3762/bjoc.19.131

• emphasized their significance in facilitating the synthesis of diverse compounds and paving the way for further advancements in the field of photocatalysis. The highly efficient construction of carbon–heteroatom (C–X) bonds is of significant importance in the fields of natural products, pharmaceuticals, and

• facilitated by the process of photoexcited radical decarboxylation. On the other hand, the copper catalytic cycle involved the capture of alkyl radicals by the copper complex B, the activation of heteroatom-containing substrates 30 by a base-mediated proton transfer, and the subsequent reductive elimination

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

• azlactone 146 skeletons. The presence of two heteroatom-bearing tetrasubstituted chiral carbon centers in a one-step fashion, avoiding the use of the heavy metal catalysts, and the performance of the reaction at ambient temperature are the prominent features of the protocol. Sahoo and co-workers found that

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

• atom(s) or another heteroatom into the vacant p-orbital (LUMO) at the carbene carbon atom (Figure 2). In fact, the donation of lone pair electrons to the carbenic center leads to an ylidic structure which induces a “push–pull” effect thereby enhancing the stability of the NHC. The cyclic structure of

• ), bear only a single flanking heteroatom and exist as a zwitterionic structure with no neutral canonical resonance form (Figure 3). In this case, binding takes place via the C4 or C5 position. These NHCs have been found to be stronger electron-donors due to the reduced σ-withdrawal from the carbene carbon

• or carbon–heteroatom double bond, resulting in the formation of a new carbon–silicon (C–Si) or heteroatom–Si (X–Si) bond (Scheme 34). This reaction is widely used in the synthesis of organosilicon compounds and in the modification of surfaces with silicon-containing molecules. NHC–Cu complexes have

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

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

• ) process, the carbocation intermediate B is generated, which is attacked by a nucleophile to afford the target product. Further, C–H bonds in the ortho-position of a heteroatom are activated through a SET pathway generating a radical cation C, which is easily deprotonated by an oxidant to generate a

• source played a key role, with lower yields or no product obtained when the reaction was performed without water or under other light source conditions such as 19 W CFL or irradiation with blue or green LEDs. This method is applicable to various heteroatom-containing compounds such as quinolines

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

• paradigm by Groves and Kochi, many groups have adopted and characterized new ways of using RLT to form valuable carbon–heteroatom bonds from a diverse pool of simple starting materials. RLT has been especially present in modern catalysis, where complexes of earth abundant iron and manganese have been

• simplified manganese salen complex I, allowing for the identity of the carbon–heteroatom bond to be controlled based on added nucleophile and enabling C–Cl, C–N, and C–S bonds to be formed directly while completely suppressing traditional ATRA products [9]. In mechanistic studies, rearrangement products

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

• lone pair of electrons of the imine nitrogen to a suitable vacant orbital of the metal center, thus enhancing the electrophilicity of the imine carbon atom by imparting a positive character on the adjacent heteroatom [22][23]. With the advent of different types of organocatalysts, the aza-Friedel

Intermediates and shunt products of massiliachelin biosynthesis in Massilia sp. NR 4-1

• Till Steinmetz,
• Blaise Kimbadi Lombe and
• Markus Nett

Beilstein J. Org. Chem. 2023, 19, 909–917, doi:10.3762/bjoc.19.69

• formula of 1 was assigned to be C15H19NO3S by high-resolution (HR) ESIMS (m/z 294.1180 [M + H]+; calcd. 294.1169 for C15H20NO3S), which indicated the presence of seven double bond equivalents (DBEs). Upon analyzing the 13C NMR spectrum, the DBEs were assigned to two ring structures, two carbon–heteroatom

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

• . Review C–H Alkylation of pyridine The C–H bond is the backbone of an organic molecule and the conversion of a C–H bond to a C–X bond (X = carbon or heteroatom) forms the basis in organic synthesis. The functionalization of C–H bonds is challenging due to a large kinetic barrier for C–H bond cleavage and

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

• ], and nanoribbons [19]. Meanwhile, to modulate the properties of synthetic hydrocarbon NGs, a variety of heteroatom-doped NGs have been constructed [8]. Chirality is a fundamental phenomenon in nature and plays an important role in science, especially in living systems. The chirality in chemistry refers

• exploit three-dimensional aesthetic structures. The continuously developed novel structures contented our interests and curiosity. To further tune the optoelectronic or photophysical properties of nanographenes for real applications, heteroatom doping was found to be an effective strategy. 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

• 10,11-dihydrodibenzo[b,f]heteropines (2). The following section will briefly touch on functionalisation of the scaffold. While some reports are limited to the introduction of a single heteroatom, e.g., nitrogen in the case of azepines 1a or oxygen in the case of oxepines 1b, some approaches allow for

• from 2-bromostyrene (116) via halogen–lithium exchange and quenching with the appropriate heteroatom source (SiR2Cl2, SnMe2Cl2, GeR2Cl2, BBr3). P-Tethered dienes were synthesised via quenching of a 2-vinylphenyl Grignard reagent with phenylphosphonic dichloride (PhPOCl2). O-Tethered dienes were

• etherification entails the palladium or copper-catalysed formation of a carbon–heteroatom bond. Despite significant successes and facile access to the core tricyclic motif, access to dibenzo[b,f]heteropines with disparately substituted aromatic rings fused to the heterocyclic ring and varied substitution

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

• dramatically depends on the nature of the heteroatom X in FPDs I, II, 1 [33][34]. It should be noted that the reactions of 5-aza- and 5-oxa-FPDs I and II with nucleophiles are studied rather well [33][34], and their reactivity did not give us any insights for the development of new approaches to PBTAs. However

Direct C2–H alkylation of indoles driven by the photochemical activity of halogen-bonded complexes

• Martina Mamone,
• Giuseppe Gentile,
• Jacopo Dosso,
• Maurizio Prato and
• Giacomo Filippini

Beilstein J. Org. Chem. 2023, 19, 575–581, doi:10.3762/bjoc.19.42

• ) and carbon–heteroatom (C–X) bonds has been and still is a central topic in organic synthesis [1][2]. Historically, organic chemists have extensively relied on the use of noble-metal-based catalysts (e.g., Pd, Rh, Ir, among others) to achieve such type of functionalization [3][4][5]. However, reliance