Pauson–Khand reaction of fluorinated compounds

• Jorge Escorihuela,
• Daniel M. Sedgwick,
• Alberto Llobat,
• Mercedes Medio-Simón,
• Pablo Barrio and
• Santos Fustero

Beilstein J. Org. Chem. 2020, 16, 1662–1682, doi:10.3762/bjoc.16.138

• corresponding mesylate 38b proved sufficient for the synthesis of N-tethered substrates 37 (Z = NTs), through simple nucleophilic substitution (via c). It is noteworthy that under standard PK reaction conditions, fluoroenyne 39 evolves to diene 40. The formation of compound 40 is possible by elimination of HF

The McKenna reaction – avoiding side reactions in phosphonate deprotection

• Katarzyna Justyna,
• Joanna Małolepsza,
• Damian Kusy,
• Waldemar Maniukiewicz and
• Katarzyna M. Błażewska

Beilstein J. Org. Chem. 2020, 16, 1436–1446, doi:10.3762/bjoc.16.119

• best of our knowledge, there were no reports on using BTMS for the nucleophilic substitution of alkyl chlorides. A similar exchange reaction was reported only for 2-chloropyridines [51], and required harsh reaction conditions, such as heating at 90–100 °C for 100 h. In this study we investigated the

Recent synthesis of thietanes

• Jiaxi Xu

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

• intramolecular nucleophilic substitution followed by an intermolecular nucleophilic displacement with the in-situ generated 1-thiabicyclo[1.1.0]butan-1-iums 399 as key intermediates. Following this route, 3-substituted thietanes 400 were prepared from reactions of 2-(1-chloroalkyl)thiiranes 398, especially

• generated thiolate in the zwitterionic intermediates 427 then further underwent an intramolecular nucleophilic substitution to yield the desired thietanes 425 by loss of a molecule of DMSO [22] (Scheme 94). 4.1.3 Synthesis via electrophilic ring expansion of thiiranes: To realize the synthesis of

Synthesis of 3-substituted isoxazolidin-4-ols using hydroboration–oxidation reactions of 4,5-unsubstituted 2,3-dihydroisoxazoles

• Lívia Dikošová,
• Júlia Laceková,
• Ondrej Záborský and
• Róbert Fischer

Beilstein J. Org. Chem. 2020, 16, 1313–1319, doi:10.3762/bjoc.16.112

• -trans relative configuration. The resemblance between 3-hydroxypyrrolidines 1 and 4-hydroxyisoxazolidines 2 (Figure 1) makes the latter valuable structural fragments in drug discovery [13][14][15][16][17][18]. Up to now, this class of compounds was commonly prepared using intramolecular nucleophilic

• substitution reactions of properly substituted hydroxylamines [19][20] and N-hydroxyphthalimides [21][22][23][24] as well as by Tamao oxidations of 4-silylisoxazolidines [25][26]. Very recently, Tomkinson et al. described a simple and effective method for an intramolecular oxyamination of allylic N-tosyl

Oxime radicals: generation, properties and application in organic synthesis

• Igor B. Krylov,
• Stanislav A. Paveliev,
• Alexander S. Budnikov and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2020, 16, 1234–1276, doi:10.3762/bjoc.16.107

• electron-withdrawing substituents decreases it (example 82e, 64%). Non-aromatic oximes of chloro- or bromoacetone are not suitable for this method; product 82f was observed in trace amounts. According to the proposed reaction pathway, the nucleophilic substitution of the halogen atom with the formation of

Synthesis and properties of quinazoline-based versatile exciplex-forming compounds

• Rasa Keruckiene,
• Simona Vekteryte,
• Ervinas Urbonas,
• Matas Guzauskas,
• Eigirdas Skuodis,
• Dmytro Volyniuk and
• Juozas V. Grazulevicius

Beilstein J. Org. Chem. 2020, 16, 1142–1153, doi:10.3762/bjoc.16.101

• an electron acceptor in donor–acceptor systems [14]. The target compounds were obtained by nucleophilic substitution reaction of the intermediate quinazoline derivative Q1 with the corresponding donor compounds. The chemical structures were characterized by 1H NMR, 13C NMR, ATRIR spectroscopy and

• compounds 1–3 were synthesized through nucleophilic substitution reactions between quinazoline derivative Q1 and the respective donor compound in the presence of sodium hydride in dry dimethylformamide (DMF). The reaction mixtures were refluxed for 24 h. After completion of the reactions, the reaction

• ): Quinazoline derivative (Q1, 0.25 g, 0.79 mmol), 3,6-di-tert-butylcarbazole (0.48 g, 1.7 mmol) and sodium hydride (0.50 g, 1.6 mmol) in dry dimethylformamide (DMF) were used for the nucleophilic substitution reaction. The title compound was obtained as yellowish crystals in a yield of 0.25 g, 37%; Tm = 181 °C

Copper-based fluorinated reagents for the synthesis of CF₂R-containing molecules (R ≠ F)

• Louise Ruyet and
• Tatiana Besset

Beilstein J. Org. Chem. 2020, 16, 1051–1065, doi:10.3762/bjoc.16.92

• on a Sandmeyer thiocyanation reaction followed by a Langlois-type nucleophilic substitution of the cyano group by the CF2PO(OEt)2 residue [55]. Several (diethylphosphono)difluoromethylthiolated products were obtained and this report further showcased the potential of using a copper-based reagent for

Recent advances in Cu-catalyzed C(sp³)–Si and C(sp³)–B bond formation

• Balaram S. Takale,
• Ruchita R. Thakore,
• Elham Etemadi-Davan and
• Bruce H. Lipshutz

Beilstein J. Org. Chem. 2020, 16, 691–737, doi:10.3762/bjoc.16.67

Regioselectively α- and β-alkynylated BODIPY dyes via gold(I)-catalyzed direct C–H functionalization and their photophysical properties

• Takahide Shimada,
• Shigeki Mori,
• Masatoshi Ishida and
• Hiroyuki Furuta

Beilstein J. Org. Chem. 2020, 16, 587–595, doi:10.3762/bjoc.16.53

• ], and borylation [32]), has been in great demand recently rather than the conventional multistep synthesis with nucleophilic substitution/cross-coupling via halogenation of BODIPYs [33] or from the activated precursors [34] via unstable pyrrolic intermediates. In particular, halogenation (e.g

Regio- and stereoselective synthesis of new ensembles of diversely functionalized 1,3-thiaselenol-2-ylmethyl selenides by a double rearrangement reaction

• Svetlana V. Amosova,
• Andrey A. Filippov,
• Nataliya A. Makhaeva,
• Alexander I. Albanov and
• Vladimir A. Potapov

Beilstein J. Org. Chem. 2020, 16, 515–523, doi:10.3762/bjoc.16.47

• the generation of sodium 1,3-thiaselenol-2-ylmethylselenolate from 1,3-thiaselenol-2-ylmethyl selenocyanate or bis(1,3-thiaselenol-2-ylmethyl) diselenide followed by nucleophilic substitution reactions. Sodium 1,3-thiaselenol-2-ylmethylselenolate underwent nucleophilic addition to alkyl propiolates in

• -thiaselenole; nucleophilic addition; nucleophilic substitution; rearrangement; seleniranium intermediate; Introduction The regio- and stereoselective synthesis of organoselenium compounds based on selenium-centered electrophilic reagents has been one of the most important and effective directions in

• represent a very interesting class of compounds with a wide range of synthetic applications [28][29]. The anchimeric assistance effect, also known as the participation of neighbouring groups, is usually considered mainly as a factor accelerating the rate of nucleophilic substitution reactions. At present

KOt-Bu-promoted selective ring-opening N-alkylation of 2-oxazolines to access 2-aminoethyl acetates and N-substituted thiazolidinones

• Qiao Lin,
• Shiling Zhang and
• Bin Li

Beilstein J. Org. Chem. 2020, 16, 492–501, doi:10.3762/bjoc.16.44

• -dihydrothiazole (Scheme 8). These experimental results suggest that the reaction may proceed through a nucleophilic substitution rather than a radical pathway. On the basis of the results collected from the control experiments and previous works in the literature, a plausible mechanism for this KOt-Bu-promoted

• ring-opening N-alkylation is illustrated in Scheme 9. The reaction is proposed to begin with the generation of iminium ether A [27][28], generated from the reaction of 2-metyl-2-oxazoline with benzyl bromide in the presence of KOt-Bu with release KBr. A subsequent second nucleophilic substitution of

Visible-light-induced addition of carboxymethanide to styrene from monochloroacetic acid

• Kaj M. van Vliet,
• Nicole S. van Leeuwen,
• Albert M. Brouwer and
• Bas de Bruin

Beilstein J. Org. Chem. 2020, 16, 398–408, doi:10.3762/bjoc.16.38

• material for the synthesis of relevant groups of compounds, many of these synthetic procedures are based on nucleophilic substitution of the carbon chlorine bond. Oxidative or reductive activation of monochloroacetic acid results in radical intermediates, leading to reactivity different from the

• traditional reactivity of this compound. Here, we investigated the possibility of applying monochloroacetic acid as a substrate for photoredox catalysis with styrene to directly produce γ-phenyl-γ-butyrolactone. Instead of using nucleophilic substitution, we cleaved the carbon chlorine bond by single-electron

• glycine and diethyl malonate, are based on nucleophilic substitution of the chlorine [6][7][8][9][10]. In an attempt to find new synthetic applications of monochloroacetic acid we turned our attention to photoredox catalysis. We were inspired by the rebirth of visible light photoredox catalysis, induced

Architecture and synthesis of P,N-heterocyclic phosphine ligands

• Wisdom A. Munzeiwa,
• Bernard Omondi and
• Vincent O. Nyamori

Beilstein J. Org. Chem. 2020, 16, 362–383, doi:10.3762/bjoc.16.35

• Preparation of N-heterocyclic phosphines via P–C bond formation Nucleophilic substitution of halogens There are different methods that have been reported for the construction of the P–C bonds. Two approaches are possible using halogenated precursors. The first one is the organometal-halogen-phosphine route

• nucleophiles compared to organometallic or metal phosphides generated through metalation processes. Hayashi et al. [66] used tris(trimethylsilyl)phosphine to control the nucleophilic substitution in the preparation of P,N-(phosphino)triazine ligands (Scheme 5). It was shown that the use of other nucleophiles

• and/or alkoxy derivatives 29–31. Selectively varying the molar ratio of the silylphosphine nucleophile and the starting reagent 25 resulted in the corresponding bis- and tris(diphenylphosphine)triazine motifs 27 and 28. A subsequent nucleophilic substitution reaction of 27 gave compounds 32 and 33

[1,3]/[1,4]-Sulfur atom migration in β-hydroxyalkylphosphine sulfides

• Katarzyna Włodarczyk,
• Piotr Borowski and
• Marek Stankevič

Beilstein J. Org. Chem. 2020, 16, 88–105, doi:10.3762/bjoc.16.11

• formed dication V underwent an intramolecular nucleophilic substitution through transition state VI, which proceeded with a small activation barrier, leading to the cyclic intermediate VII and further to the rearranged product 54. The tentative mechanism discussed above does not explain the formation of

A green, economical synthesis of β-ketonitriles and trifunctionalized building blocks from esters and lactones

• Daniel P. Pienaar,
• Kamogelo R. Butsi,
• Amanda L. Rousseau and
• Dean Brady

Beilstein J. Org. Chem. 2019, 15, 2930–2935, doi:10.3762/bjoc.15.287

• solvent is effectively lowered by adding a small amount of polar, protic IPA and this facilitates acetonitrile deprotonation. Alternatively, the addition of a crown ether is also known to enhance nucleophilic substitution reaction rates, but in this case through the suppression of ion-pairing [16]. We

A review of asymmetric synthetic organic electrochemistry and electrocatalysis: concepts, applications, recent developments and future directions

• Munmun Ghosh,
• Valmik S. Shinde and
• Magnus Rueping

Beilstein J. Org. Chem. 2019, 15, 2710–2746, doi:10.3762/bjoc.15.264

• . Further nucleophilic substitution of 174 with allyltrimethylsilane in the presence of a Lewis acid afforded α-alkylated products 175. The highest de was obtained in the case of 175d. The deprotection of 175 with LAH enabled access to α-alkylated pyrrolidines 176 with the release of 177 (Scheme 56). In

Safe and highly efficient adaptation of potentially explosive azide chemistry involved in the synthesis of Tamiflu using continuous-flow technology

• Cloudius R. Sagandira and
• Paul Watts

Beilstein J. Org. Chem. 2019, 15, 2577–2589, doi:10.3762/bjoc.15.251

• suitable azidating agent undergoes a highly regio- and stereoselective nucleophilic substitution of allylic O-mesylate at the C-3 position affording azide compound 5 (Scheme 3). Nie and co-workers [19] reported the treatment of mesyl shikimate 4 with NaN3 (4 equiv) in aqueous acetone (Me2CO/H2O 5:1) at 0

Synthesis of novel sulfide-based cyclic peptidomimetic analogues to solonamides

• José Brango-Vanegas,
• Luan A. Martinho,
• Lucinda J. Bessa,
• Andreanne G. Vasconcelos,
• Alexandra Plácido,
• Alex L. Pereira,
• José R. S. A. Leite and
• Angelo H. L. Machado

Beilstein J. Org. Chem. 2019, 15, 2544–2551, doi:10.3762/bjoc.15.247

• structurally related to these natural peptidomimetics has been used as a promising strategy for the attenuation of bacterial virulence in strains of S. aureus [12][13][14][15]. Herein, we report the synthesis of new sulfide-based cyclic peptidomimetics through the allylic nucleophilic substitution (SN2’) of

A toolbox of molecular photoswitches to modulate the CXCR3 chemokine receptor with light

• Xavier Gómez-Santacana,
• Sabrina M. de Munnik,
• Tamara A. M. Mocking,
• Niels J. Hauwert,
• Shanliang Sun,
• Prashanna Vijayachandran,
• Iwan J. P. de Esch,
• Henry F. Vischer,
• Maikel Wijtmans and
• Rob Leurs

Beilstein J. Org. Chem. 2019, 15, 2509–2523, doi:10.3762/bjoc.15.244

• advanced intermediate 28b (Scheme 3), which was subjected to an aromatic nucleophilic substitution with potassium phthalimide prepared in situ from 29 and K2CO3. Presumably due to the alkaline medium, the phthalimide ring was partially opened as detected by HPLC–MS. Upon attempted re-closing under reflux

Synthesis of a dihalogenated pyridinyl silicon rhodamine for mitochondrial imaging by a halogen dance rearrangement

• Jessica Matthias,
• Thines Kanagasundaram,
• Klaus Kopka and
• Carsten S. Kramer

Beilstein J. Org. Chem. 2019, 15, 2333–2343, doi:10.3762/bjoc.15.226

• at the bromine via a nucleophilic substitution, we explored also if the ester analogue tert-butyl 5-bromo-6-chloronicotinate could undergo a HD reaction with subsequent xanthone addition. The reaction did not lead to any product, neither with n-BuLi nor with t-BuLi. However, it is noteworthy that no

Fluorescent phosphorus dendrimers excited by two photons: synthesis, two-photon absorption properties and biological uses

• Anne-Marie Caminade,
• Artem Zibarov,
• Eduardo Cueto Diaz,
• Aurélien Hameau,
• Maxime Klausen,
• Kathleen Moineau-Chane Ching,
• Jean-Pierre Majoral,
• Jean-Baptiste Verlhac,
• Olivier Mongin and
• Mireille Blanchard-Desce

Beilstein J. Org. Chem. 2019, 15, 2287–2303, doi:10.3762/bjoc.15.221

• N3P3Cl6 [33], the first step is the nucleophilic substitution with 4-hydroxybenzaldehyde in basic conditions. The second step comprises the condensation reaction of the aldehyde terminal functions with the phosphorhydrazide H2NNMeP(S)Cl2. This reaction affords the first generation (G1) dendrimer, having

1,2,3-Triazolium macrocycles in supramolecular chemistry

• Mastaneh Safarnejad Shad,
• Pulikkal Veettil Santhini and
• Wim Dehaen

Beilstein J. Org. Chem. 2019, 15, 2142–2155, doi:10.3762/bjoc.15.211

• -position of the triazoles (triazolium), and nucleophilic substitution of halogen can be used to introduce chalcogens (Se, Te). Thus, the corresponding triazolium macrocycles can take advantage respectively of halogen and chalcogen bonding as part of the molecular recognition (vide infra). In this review

Synthesis and properties of sulfur-functionalized triarylmethylium, acridinium and triangulenium dyes

• Marco Santella,
• Eduardo Della Pia,
• Jakob Kryger Sørensen and
• Bo W. Laursen

Beilstein J. Org. Chem. 2019, 15, 2133–2141, doi:10.3762/bjoc.15.210

• functionalities were synthesized and their optical properties were studied. The sulfur functionalities were introduced by aromatic nucleophilic substitution of methoxy groups in triarylmethylium cations with ethanethiol followed by partial or full ring closure of the ortho positions with nitrogen or oxygen

• of the ethylthiol substituents. For the triangulenium derivatives significant fluorescence was observed (Φf = 0.1 to Φf = 0.3). Keywords: acridinium dyes; aromatic nucleophilic substitution; fluorescent dyes; sulfur-functionalized dyes; triangulenium dyes; triarylmethylium; Introduction The design

• -substituted triarylmethylium salts as simple precursors allowing both introduction of dialkylamino donor groups and formation of the heterocyclic triangulenium ring systems. These characteristic types of aromatic nucleophilic substitution (SNAr) reactions are exemplified by the synthesis of A3-ADOTA+ (Figure

Recent advances on the transition-metal-catalyzed synthesis of imidazopyridines: an updated coverage

• Gagandeep Kour Reen,
• Ashok Kumar and
• Pratibha Sharma

Beilstein J. Org. Chem. 2019, 15, 1612–1704, doi:10.3762/bjoc.15.165

• ) [119]. In this reaction, iodine promoted the formation of iodo-intermediate 98 with a carbonyl compound that underwent nucleophilic substitution with 2-AP 3. CuO played multiple roles in this reaction. Firstly it acts as an oxidizing agent to convert molecular iodine to the reactive iodonium ion (I

Synthesis of 9-O-arylated berberines via copper-catalyzed C_Ar–O coupling reactions

• Qiaoqiao Teng,
• Xinhui Zhu,
• Qianqian Guo,
• Weihua Jiang,
• Jiang Liu and
• Qi Meng

Beilstein J. Org. Chem. 2019, 15, 1575–1580, doi:10.3762/bjoc.15.161

• temperature, during which 9-O-methyl cleavage occurs. The resulting berberrubine (BBRB) then acts as a good precursor to 9-O-substituted derivatives through nucleophilic substitution reactions with alkyl halides (Scheme 1). By this route, not only long-chain alkyl substituents were installed, but also more