Design, synthesis and photophysical properties of novel star-shaped truxene-based heterocycles utilizing ring-closing metathesis, Clauson–Kaas, Van Leusen and Ullmann-type reactions as key tools

• Shakeel Alvi and
• Rashid Ali

Beilstein J. Org. Chem. 2021, 17, 1374–1384, doi:10.3762/bjoc.17.96

• -closing metathesis (RCM), Clauson–Kaas and Ullmann-type coupling reactions as key steps. Moreover, we have also assembled some other interesting heterocyclic systems possessing oxazole, imidazole, benzimidazole, and benzoxazole in the framework of truxene. Additionally, the preliminary photophysical

N-tert-Butanesulfinyl imines in the asymmetric synthesis of nitrogen-containing heterocycles

• Joseane A. Mendes,
• Paulo R. R. Costa,
• Miguel Yus,
• Francisco Foubelo and
• Camilla D. Buarque

Beilstein J. Org. Chem. 2021, 17, 1096–1140, doi:10.3762/bjoc.17.86

• )-configuration. Excellent diastereoselectivities were also achieved in the indium-mediated allylation of chiral tert-butanesulfinyl glyoxylate imine derivatives 87 with ethyl 2-bromomethylacrylate (88). Working at room temperature without any additional solvent provided the highest yields in these coupling

• reactions, amino diesters 89 being isolated as single diastereoisomers (Scheme 27). Removal of the sulfinyl group under acidic conditions, and further treatment of the resulting ammonium salts with sodium ethoxide, yielded α-methylene-γ-butyrolactams 90, in a one-pot, two-step process [103]. A six-membered

Synthesis of 10-O-aryl-substituted berberine derivatives by Chan–Evans–Lam coupling and investigation of their DNA-binding properties

• Peter Jonas Wickhorst,
• Mathilda Blachnik,
• Denisa Lagumdzija and
• Heiko Ihmels

Beilstein J. Org. Chem. 2021, 17, 991–1000, doi:10.3762/bjoc.17.81

• -DNA by terminal stacking. Keywords: berberine alkaloids; Cu-mediated coupling reactions; DNA recognition; nucleic acids; quadruplex DNA; Introduction Berberine (1a) is the most prominent member of the protoberberine family, i.e., a group of tetracyclic isoquinolinium alkaloids [1]. Like many members

• substitution [17][18][19][20][21] of berberrubine (1b) have been performed, whereas the direct O-arylation of berberrubine has not been accomplished, yet, most likely because the substrate is not fully compatible with the usual conditions of the corresponding Ullmann or Buchwald–Hartwig coupling reactions

Beyond ribose and phosphate: Selected nucleic acid modifications for structure–function investigations and therapeutic applications

• Christopher Liczner,
• Kieran Duke,
• Gabrielle Juneau,
• Martin Egli and
• Christopher J. Wilds

Beilstein J. Org. Chem. 2021, 17, 908–931, doi:10.3762/bjoc.17.76

• synthetic route being optimized over time [151][152]. The stability of these derivatives is similar to those of LNA [150][151][152], with the added advantage of additional coupling reactions to fluorescent groups [151], or small molecules being possible either during solid-phase synthesis (SPS) [153][154

Manganese/bipyridine-catalyzed non-directed C(sp³)–H bromination using NBS and TMSN₃

• Kumar Sneh,
• Takeru Torigoe and
• Yoichiro Kuninobu

Beilstein J. Org. Chem. 2021, 17, 885–890, doi:10.3762/bjoc.17.74

• variety of functionalities, such as boron-, silicon-, nitrogen-, and oxygen-based functional groups, and in C−C bond forming reactions, such as cross-coupling reactions [1][2][3][4][5][6]. The traditional method used for the preparation of alkyl bromides is the reaction of their corresponding alkyl

Highly regio- and stereoselective phosphinylphosphination of terminal alkynes with tetraphenyldiphosphine monoxide under radical conditions

• Dat Phuc Tran,
• Yuki Sato,
• Yuki Yamamoto,
• Shin-ichi Kawaguchi,
• Shintaro Kodama,
• Akihiro Nomoto and
• Akiya Ogawa

Beilstein J. Org. Chem. 2021, 17, 866–872, doi:10.3762/bjoc.17.72

• as 1,2-bis(diphenylphosphino)ethane (Ph2PCH2CH2PPh2, dppe) are employed as bidentate ligands and are effective in controlling important catalytic reactions such as cross-coupling reactions [9][10][11][12][13][14][15][16][17][18]. 1,2-Bis(diphenylphosphino)ethylene (Ph2PCH=CHPPh2, dppen) is among

A chromatography-free and aqueous waste-free process for thioamide preparation with Lawesson’s reagent

• Ke Wu,
• Yichen Ling,
• An Ding,
• Liqun Jin,
• Nan Sun,
• Baoxiang Hu,
• Zhenlu Shen and
• Xinquan Hu

Beilstein J. Org. Chem. 2021, 17, 805–812, doi:10.3762/bjoc.17.69

• -coupling reactions [28][29][30][31][32][33][34][35]. The thio-substitution of amides with LR is an efficient and straightforward method, because the amide substrates and LR are readily available and the reactions are easily operated [8][9][36][37][38][39][40]. With thio-substitution of amides as a model

Synthetic reactions driven by electron-donor–acceptor (EDA) complexes

• Zhonglie Yang,
• Yutong Liu,
• Kun Cao,
• Xiaobin Zhang,
• Hezhong Jiang and
• Jiahong Li

Beilstein J. Org. Chem. 2021, 17, 771–799, doi:10.3762/bjoc.17.67

• -metal catalysts, such as in the Suzuki–Miyaura and Heck coupling reactions. Methodologies for forming different C–C bonds have recently been developed in the field of single-electron chemistry [63][64][65]. Considering that EDA-complex-initiated free-radical reactions are carried out under mild

The preparation and properties of 1,1-difluorocyclopropane derivatives

• Kymbat S. Adekenova,
• Peter B. Wyatt and
• Sergazy M. Adekenov

Beilstein J. Org. Chem. 2021, 17, 245–272, doi:10.3762/bjoc.17.25

Selective synthesis of α-organylthio esters and α-organylthio ketones from β-keto esters and sodium S-organyl sulfurothioates under basic conditions

• Jean C. Kazmierczak,
• Roberta Cargnelutti,
• Thiago Barcellos,
• Claudio C. Silveira and
• Ricardo F. Schumacher

Beilstein J. Org. Chem. 2021, 17, 234–244, doi:10.3762/bjoc.17.24

• -rich N-heterocycles [2][3][4], decarboxylative cross-coupling reactions with propiolic acid derivatives [5], Michael addition reaction [6], cross-couplings catalyzed by Pd [7] and Cu salts [8][9], the preparation of symmetrical and nonsymmetrical disulfides [10][11], and the synthesis of β-acetamido

Progress in the total synthesis of inthomycins

• Bidyut Kumar Senapati

Beilstein J. Org. Chem. 2021, 17, 58–82, doi:10.3762/bjoc.17.7

• synthetic efforts toward neooxazolomycin (4), oxazolomycin A (5a), and related antibiotics [17]. The recent review of Lee has mainly focused on the application of copper(I) salt and fluoride-promoted Stille coupling reactions in the synthesis of bioactive molecules including inthomycins A–C (1–3) [18]. The

• functional groups and isomerizable double bonds in the conjugated triene moiety. Various stereoselective cross-coupling reactions such as Stille, Suzuki, or Sonogashira or Suzuki–Miyaura have been utilized to construct the geometrically distinctive polyene systems of inthomycins A–C (1–3). The elegant work

Metal-free synthesis of biarenes via photoextrusion in di(tri)aryl phosphates

• Hisham Qrareya,
• Lorenzo Meazza,
• Stefano Protti and
• Maurizio Fagnoni

Beilstein J. Org. Chem. 2020, 16, 3008–3014, doi:10.3762/bjoc.16.250

• challenge [11][12][13]. Common methods, such as the Ullmann and Gomberg synthesis [14][15][16] have been nowadays supplanted by the much more versatile metal-catalyzed cross-coupling reactions [17][18][19][20][21][22][23]. This excellent approach still encounters some limitation in the scope and in the

• results and of the reported literature [58][61], to the singlet monomeric excited state and to the exciplex, respectively. While aryl phosphates have been only sparsely used as substrates in thermal cross-coupling reactions [65][66][67], their photochemical behavior has been the subject of various

Changed reactivity of secondary hydroxy groups in C8-modified adenosine – lessons learned from silylation

• Jennifer Frommer and
• Sabine Müller

Beilstein J. Org. Chem. 2020, 16, 2854–2861, doi:10.3762/bjoc.16.234

• is desired, in order to introduce two or even more functionalities in a specific manner. For example, in earlier work we have used amine-NHS coupling reactions in combination with CuAAC to prepare double labeled RNA molecules for FRET analysis [19]. The conjugation of, sometimes rather large

Palladium nanoparticles supported on chitin-based nanomaterials as heterogeneous catalysts for the Heck coupling reaction

• Tony Jin,
• Malickah Hicks,
• Davis Kurdyla,
• Sabahudin Hrapovic,
• Edmond Lam and
• Audrey Moores

Beilstein J. Org. Chem. 2020, 16, 2477–2483, doi:10.3762/bjoc.16.201

• benign conditions, outcompeting the use of other catalysts supported on biomass-based nanomaterials, including cellulose nanocrystals. These initial results show the potential for using chitinous nanomaterials as effective catalyst supports in cross-coupling reactions. Keywords: chitin; chitosan; Heck

• and aldehyde–amine–alkyne (A3) coupling reactions [16]. Off this discovery, in this letter, we further expand the scope of using both ChNCs and ChsNCs as a catalyst support for Pd NPs to allow access towards other highly relevant C–C bond-forming reactions. A one-pot fabrication method is used to

• to PdNP@ChNC, PdNP@ChsNC showed little product yield in the model reaction (Table 1, entry 6), which was surprising as our previous works showed that ChsNC was the superior catalyst support for Au-catalyzed A3 coupling reactions [16]. The XPS analysis of PdNP@ChsNC suggests that Pd is complexed to

Recent developments in enantioselective photocatalysis

• Callum Prentice,
• James Morrisson,
• Andrew D. Smith and
• Eli Zysman-Colman

Beilstein J. Org. Chem. 2020, 16, 2363–2441, doi:10.3762/bjoc.16.197

•  18b) [65]. Jiang et al. also reported a series of radical coupling reactions using different CPAs 135a–g and DPZ, with the first examples using α-bromoketones 136 and α-amino acids 137 as radical precursors (Scheme 19a) [66]. The proposed mechanism proceeds through a reductive quenching cycle to

Synthesis of 1,4-benzothiazinones from acylpyruvic acids or furan-2,3-diones and o-aminothiophenol

• Ekaterina E. Stepanova,
• Maksim V. Dmitriev and
• Andrey N. Maslivets

Beilstein J. Org. Chem. 2020, 16, 2322–2331, doi:10.3762/bjoc.16.193

• additives for carbodiimide coupling reactions, DMAP [30] and HOBt [31]. The utilization of HOBt (Table 1, entries 25 and 26) in acetonitrile as an additive did not significantly influence the yield of BTA 3a. But since the solubility of HOBt in acetonitrile is poor [32], we examined the reaction in DMF and

Chan–Evans–Lam N1-(het)arylation and N1-alkеnylation of 4-fluoroalkylpyrimidin-2(1H)-ones

• Viktor M. Tkachuk,
• Oleh O. Lukianov,
• Mykhailo V. Vovk,
• Isabelle Gillaizeau and
• Volodymyr A. Sukach

Beilstein J. Org. Chem. 2020, 16, 2304–2313, doi:10.3762/bjoc.16.191

• uniquely advantageous means to perform C–N cross-coupling reactions [15][16][17]. The corresponding Ullmann-type reaction currently known as Chan–Evans–Lam (CEL) coupling is characterized by the combination of two nucleophilic reactants which implies that oxidative processes with atmospheric oxygen play a

The biomimetic synthesis of balsaminone A and ellagic acid via oxidative dimerization

• Sharna-kay Daley and
• Nadale Downer-Riley

Beilstein J. Org. Chem. 2020, 16, 2026–2031, doi:10.3762/bjoc.16.169

• establish high-yielding and selective oxidative coupling reactions, has afforded new and greener synthetic protocols for biaryls [5][6][7]. Several oxidants, such as the salts of Ag(I&II) [8], Ti(III&IV) [9], Mn(III) [10], Ce(IV) [11], Sn(IV) [12] and Fe(III) [13], as well as the hypervalent iodine reagents

Synergy between supported ionic liquid-like phases and immobilized palladium N-heterocyclic carbene–phosphine complexes for the Negishi reaction under flow conditions

• Edgar Peris,
• Raúl Porcar,
• María Macia,
• Jesús Alcázar,
• Eduardo García-Verdugo and
• Santiago V. Luis

Beilstein J. Org. Chem. 2020, 16, 1924–1935, doi:10.3762/bjoc.16.159

• modulated through systematic variations of the steric and electronic design vectors of the NHC ligand [2]. These complexes have been used as highly efficient catalysts for a wide variety of C–C and C–X cross-coupling reactions [3]. Among others, different NHC–Pd complexes have been designed as efficient

• complexes enabling a simpler recovery and reuse of the catalysts by filtration [5]. Furthermore, the immobilized NHC-complexes can be easily adapted to flow processes using a fix-bed reactor set-up increasing simultaneously the sustainability and the efficiency of the C–C coupling reactions [6][7]. In the

• pursuit of NHC immobilized metal complexes many different materials of organic and inorganic nature have been used as supports [5]. Several reports describe the synthesis of supported palladium–NHC complexes (Pd–NHC) and their application in cross-coupling reactions [8][9][10]. The main flaw of this type

Regiodivergent synthesis of functionalized pyrimidines and imidazoles through phenacyl azides in deep eutectic solvents

• Paola Vitale,
• Luciana Cicco,
• Ilaria Cellamare,
• Filippo M. Perna,
• Antonio Salomone and
• Vito Capriati

Beilstein J. Org. Chem. 2020, 16, 1915–1923, doi:10.3762/bjoc.16.158

• ], (c) carbon–sulfur bond-forming reactions [9], (d) directed ortho-metalation and nucleophilic acyl substitution strategies [10], (e) Pd-catalyzed aminocarbonylation of aryl iodides, Suzuki–Miyaura and Sonogashira cross-coupling reactions [11][12][13], (f) Cu-catalyzed C–N coupling reactions [14], and

• cross-coupling reactions. A 4-fluoro-substituted phenacyl chloride as well as a bromomethyl 2-naphthyl ketone proved to be competent substrates as well, thus furnishing the corresponding imidazoles 3i/3i' and 3j in 67–87% yield. Conversely, a phenacyl halide decorated with an additional phenyl group at

When metal-catalyzed C–H functionalization meets visible-light photocatalysis

• Lucas Guillemard and
• Joanna Wencel-Delord

Beilstein J. Org. Chem. 2020, 16, 1754–1804, doi:10.3762/bjoc.16.147

• , thus rendering this methodology well suitable for the synthesis of a variety of indole derivatives. Subsequently, the panel of oxidative Heck coupling reactions via a photoredox catalytic system combined with C–H activation using Rh [74] or Ru [75] was extended by Rueping’s group. In 2014, Rueping

Tuneable access to indole, indolone, and cinnoline derivatives from a common 1,4-diketone Michael acceptor

• Dalel El-Marrouki,
• Sabrina Touchet,
• Abderrahmen Abdelli,
• Hédi M’Rabet,
• Mohamed Lotfi Efrit and
• Philippe C. Gros

Beilstein J. Org. Chem. 2020, 16, 1722–1731, doi:10.3762/bjoc.16.144

• ][38][39] or triketones [10][13] and enaminones [40][41][42][43] as starting materials. For the synthesis of cinnoline derivatives, aryldiazenes and aryltriazenes are substrates of choice for transition-metal-catalyzed (Rh, Pd, Cu) cross-coupling reactions, followed by intramolecular cyclizations [44

In silico rationalisation of selectivity and reactivity in Pd-catalysed C–H activation reactions

• Liwei Cao,
• Mikhail Kabeshov,
• Steven V. Ley and
• Alexei A. Lapkin

Beilstein J. Org. Chem. 2020, 16, 1465–1475, doi:10.3762/bjoc.16.122

• synthetic strategies. Such examples in recent years include olefin metathesis [1] as well as C–C and C–N coupling reactions [2], among the most obvious examples. While these reactions undoubtedly had very significant impacts on the development of much cleaner and efficient chemical synthesis strategies, the

One-pot synthesis of 1,3,5-triazine-2,4-dithione derivatives via three-component reactions

• Gui-Feng Kang and
• Gang Zhang

Beilstein J. Org. Chem. 2020, 16, 1447–1455, doi:10.3762/bjoc.16.120

• with the reaction conditions and yielded the corresponding products (6oa–va, 48–92%), allowing for further functionalization through subsequent transition-metal-catalyzed coupling reactions. Intriguingly, it was found that compounds with bicycloaryl and heteroaryl ring systems were also viable

Recent synthesis of thietanes

• Jiaxi Xu

Beilstein J. Org. Chem. 2020, 16, 1357–1410, doi:10.3762/bjoc.16.116