Organocatalytic asymmetric Michael/acyl transfer reaction between α-nitroketones and 4-arylidenepyrrolidine-2,3-diones

• Chandrakanta Parida and
• Subhas Chandra Pan

Beilstein J. Org. Chem. 2021, 17, 1447–1452, doi:10.3762/bjoc.17.100

• ; pyrrolidine-2,3-dione; Introduction The Michael reaction is a powerful reaction that has been so far applied for the formation of carbon–carbon and carbon–heteroatom bonds in organic synthesis [1][2]. After the renaissance of organocatalysis in the year 2000, this field has been applied tremendously for the

Fritsch–Buttenberg–Wiechell rearrangement of magnesium alkylidene carbenoids leading to the formation of alkynes

• Tsutomu Kimura,
• Koto Sekiguchi,
• Akane Ando and
• Aki Imafuji

Beilstein J. Org. Chem. 2021, 17, 1352–1359, doi:10.3762/bjoc.17.94

• magnesium alkylidene carbenoids was studied by using 13C-labeled sulfoxides and by using DFT calculations. Keywords: alkyne; 1-chlorovinyl p-tolyl sulfoxide; DFT calculation; Fritsch–Buttenberg–Wiechell rearrangement; magnesium alkylidene carbenoid; Introduction Alkynes are important compounds in organic

• synthesis [1]. Electrophilic additions of alkynes give functionalized compounds, and cycloadditions such as the Huisgen reaction afford cyclic compounds. Weakly acidic terminal alkynes can be deprotonated, and the resulting acetylides are used as carbon nucleophiles. Terminal alkynes are also used for the

Icilio Guareschi and his amazing “1897 reaction”

• Gian Cesare Tron,
• Alberto Minassi,
• Giovanni Sorba,
• Mara Fausone and
• Giovanni Appendino

Beilstein J. Org. Chem. 2021, 17, 1335–1351, doi:10.3762/bjoc.17.93

A comprehensive review of flow chemistry techniques tailored to the flavours and fragrances industries

• Guido Gambacorta,
• James S. Sharley and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2021, 17, 1181–1312, doi:10.3762/bjoc.17.90

• temperatures, fragrance ingredients/intermediates make ideal candidates for continuous-flow manufacturing. This review highlights the potential crossover between a multibillion dollar industry and the flourishing sub-field of flow chemistry evolving within the discipline of organic synthesis. This is

• simplicity and complexity represented by the different scent molecules is impressive (Figure 4). The advantages of a flow approach Flow chemistry as a branch of organic synthesis has been reviewed extensively through several informative and educational articles [14][15][16][17][18][19][20][21] and books [22

• research and manufacturing setting [28][29][30][31][32]. The massive increase in interest towards flow chemistry throughout the field of organic synthesis has been aided in part by the advent and increasing availability of lab-scale flow systems designed by both academic and industrial sectors. The

Heterogeneous photocatalytic cyanomethylarylation of alkenes with acetonitrile: synthesis of diverse nitrogenous heterocyclic compounds

• Guanglong Pan,
• Qian Yang,
• Wentao Wang,
• Yurong Tang and
• Yunfei Cai

Beilstein J. Org. Chem. 2021, 17, 1171–1180, doi:10.3762/bjoc.17.89

• microwave stimulations [18][19][20][21][22][23][24][25][26]. Recently, visible light photoredox catalysis has emerged as a powerful and environment-friendly method in organic synthesis by activating organic molecules under mild reaction conditions [27][28]. In this context, the Li and Cai groups

• given its low cost, recyclability, and high chemical/thermal stability [37][38][39]. Meanwhile, CN-K has a band gap of 2.72 eV with suitable valence band and conduction band potentials, which allows its promising use in organic synthesis for oxidation and reduction of various substrates [40][41][42][43

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

• hand, natural amino acids proline and hydroxyproline are functionalized pyrrolidines that have found great application in organic synthesis as chiral organocatalysts in stereoselective processes [93][94]. Cyclizations involving a position in the starting chiral imine Arylation of chiral sulfinyl imines

Synthetic accesses to biguanide compounds

• Oleksandr Grytsai,
• Cyril Ronco and
• Rachid Benhida

Beilstein J. Org. Chem. 2021, 17, 1001–1040, doi:10.3762/bjoc.17.82

• materials in organic synthesis for the preparation of nitrogen-containing heterocycles. Moreover, biguanides demonstrate a wide range of biological activities and some representatives are worldwide known such as metformin, the first-line treatment against type II diabetes, or chlorhexidine, the gold

• on this feature to isolate biguanide as a copper complex. Interestingly, transition metal-biguanide complexes often present vivid colors because of a strong absorption in the visible range. Biguanides have been used in chemistry as versatile starting materials in organic synthesis, catalysts [5

• ], superbases [6], and as ligands for metal complexation [7]. In organic synthesis, biguanides are precursors to several heterocycles [1] such as 1,3,5-triazines, pyrimidines, boron heterocycles, and benzo[f]quinazolines. The application of biguanides as catalysts has been reported mostly for the

Metal-free glycosylation with glycosyl fluorides in liquid SO₂

• Krista Gulbe,
• Jevgeņija Lugiņina,
• Edijs Jansons,
• Artis Kinens and
• Māris Turks

Beilstein J. Org. Chem. 2021, 17, 964–976, doi:10.3762/bjoc.17.78

• Krista Gulbe Jevgenija Luginina Edijs Jansons Artis Kinens Maris Turks Institute of Technology of Organic Chemistry, Faculty of Materials Science and Applied Chemistry, Riga Technical University, P. Valdena str. 3, Riga, LV-1048, Latvia Latvian Institute of Organic Synthesis, Aizkraukles str. 21

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

Microwave-assisted multicomponent reactions in heterocyclic chemistry and mechanistic aspects

• Shivani Gulati,
• Stephy Elza John and
• Nagula Shankaraiah

Beilstein J. Org. Chem. 2021, 17, 819–865, doi:10.3762/bjoc.17.71

• -assisted (MWA) organic synthesis marked its presence on the scientific map in 1986 with two reports of organic syntheses in the kitchen microwave [13][14]. This paved a new direction in synthetic chemistry wherein technology was incorporated to achieve the desired results adroitly. The golden decade of MWA

• organic synthesis (2000–10), witnessed microwaves with optic fibre or IR pyrometers for temperature detection along with specific glass reaction vessels that can withstand pressure and temperature in the reaction generated especially by low boiling solvents. Microwave-assisted heating reduces reaction

• transferred through convection to the participating reactants [15][16][17][18][19]. Over the years, microwave reactors have undergone considerable changes making it adaptable at various levels of organic synthesis. Primarily, there are three types of microwave reactors namely monomode microwave reactors

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

• Electron transfer (ET) is a very common occurrence in the field of natural science, including photochemical, electrochemical, and enzymatic reactions and even major organic synthesis. From 1950 to 1952, Mulliken suggested an electron transfer hypothesis that could more precisely explain electron transfer

• protocol reveals a high functional-group tolerance that permits the transformation into boronic esters of natural alcohol products with high stereocontrol. The construction of C–N bonds The development of efficient methods to construct C–N bonds is an essential scheme in organic synthesis due to its

• them in view of their great significance in organic synthesis. In 2018, Miyake and colleagues [50] found a protocol for the preparation of (Z)-2-iodovinyl phenyl ether 168 by utilizing ethynylbenziodoxol(on)e (EBX) 167 and phenol derivative 166 (Scheme 59). Due to the lack of significant electronic

Synthesis of β-triazolylenones via metal-free desulfonylative alkylation of N-tosyl-1,2,3-triazoles

• Soumyaranjan Pati,
• Renata G. Almeida,
• Eufrânio N. da Silva Júnior and
• Irishi N. N. Namboothiri

Beilstein J. Org. Chem. 2021, 17, 762–770, doi:10.3762/bjoc.17.66

• , cefatrizine, rufinamide and JNJ-54175446 (Scheme 1a) [10]. In addition to their biological activities, triazolic compounds are widely employed in organic synthesis and have outstanding synthetic versatility. In this sense, extensive scientific research has been conducted using triazoles as synthetic

• conditions is highly desirable. From another perspective, compounds containing a 1,3-dicarbonyl moiety are essential building blocks in organic synthesis whose reactivity is well-established in the literature [34][35]. Besides, these are the precursors of β-enamines which are employed for the synthesis of

β-Lactamase inhibition profile of new amidine-substituted diazabicyclooctanes

• Zafar Iqbal,
• Lijuan Zhai,
• Yuanyu Gao,
• Dong Tang,
• Xueqin Ma,
• Jinbo Ji,
• Jian Sun,
• Jingwen Ji,
• Yuanbai Liu,
• Rui Jiang,
• Yangxiu Mu,
• Lili He,
• Haikang Yang and
• Zhixiang Yang

Beilstein J. Org. Chem. 2021, 17, 711–718, doi:10.3762/bjoc.17.60

• Zafar Iqbal Lijuan Zhai Yuanyu Gao Dong Tang Xueqin Ma Jinbo Ji Jian Sun Jingwen Ji Yuanbai Liu Rui Jiang Yangxiu Mu Lili He Haikang Yang Zhixiang Yang Ningxia Centre of Organic Synthesis and Engineering Technology, Ningxia Academy of Agriculture and Forestry Sciences, No. 590, Huanghe East Road

Stereoselective syntheses of 3-aminocyclooctanetriols and halocyclooctanetriols

• Emine Salamci and
• Yunus Zozik

Beilstein J. Org. Chem. 2021, 17, 705–710, doi:10.3762/bjoc.17.59

• of the most important conduramines 4 is valienamine (3) [17], which is found as a building block in several aminoglycoside antibiotics [2]. Furthermore, conduramines 4 and their derivatives are used as both inhibitors of glycosidases and useful intermediates in organic synthesis [18]. Halocyclitols

Synthesis, structural characterization, and optical properties of benzo[f]naphtho[2,3-b]phosphoindoles

• Mio Matsumura,
• Takahiro Teramoto,
• Masato Kawakubo,
• Masatoshi Kawahata,
• Yuki Murata,
• Kentaro Yamaguchi,
• Masanobu Uchiyama and
• Shuji Yasuike

Beilstein J. Org. Chem. 2021, 17, 671–677, doi:10.3762/bjoc.17.56

• property; phosphorus; Introduction Phosphole-based heteroacenes are attracting increasing interest in various fields, such as organic synthesis, structural chemistry, and materials science [1][2][3][4]. The phosphorus atom of trivalent phosphorus compounds has a high chemical reactivity. Therefore, this

Mesoionic tetrazolium-5-aminides: Synthesis, molecular and crystal structures, UV–vis spectra, and DFT calculations

• Vladislav A. Budevich,
• Sergei V. Voitekhovich,
• Alexander V. Zuraev,
• Vadim E. Matulis,
• Vitaly E. Matulis,
• Alexander S. Lyakhov,
• Ludmila S. Ivashkevich and
• Oleg A. Ivashkevich

Beilstein J. Org. Chem. 2021, 17, 385–395, doi:10.3762/bjoc.17.34

• -generator and blowing agent [1][2]. Moreover, it is a useful building block in organic synthesis, including various multicomponent reactions opening the way to diverse fused heterocycles [3]. Salts with anionic tetrazole, i.e., aminotetrazolates 2, and cationic ones, i.e., aminotetrazolium salts 3, are

CF₃-substituted carbocations: underexploited intermediates with great potential in modern synthetic chemistry

• Anthony J. Fernandes,
• Armen Panossian,
• Bastien Michelet,
• Agnès Martin-Mingot,
• Frédéric R. Leroux and
• Sébastien Thibaudeau

Beilstein J. Org. Chem. 2021, 17, 343–378, doi:10.3762/bjoc.17.32

• long been investigated. This review highlights recent and past reports focusing on their study and potential in modern synthetic transformations. Keywords: carbocation; organic synthesis; superelectrophile; trifluoromethyl; Introduction Carbocations are pivotal intermediates in organic chemistry, and

• mentioned features, with Δδ19F = +16.7 ppm and ΔνCO ≈ +50 cm−1. Beyond the synthetic challenges associated with the generation of such species, the authors explored their use in organic synthesis. These metal-stabilized α-(trifluoromethyl)propargylium ions 114 could be engaged in useful transformations

• intermediate in these reactions is supposed to be α-(trifluoromethyl)propargylium ion 133↔133’. Heteroatom-substituted α-(trifluoromethyl)carbenium ions The stabilization of carbenium ions through oxygen lone pair back-donation [35] is a common feature in organic synthesis [88][89][90]. In this context, Olah

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

• difluorocarbenes became available. These methods contributed to the synthesis of a wide variety of fluorinated cyclopropanes. In 2003, two reviews by Dolbier [7] and Fedorynski [8] were published on the methods of synthesis and use of difluorocyclopropanes in organic synthesis. They discussed in detail the various

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

• sulfides by the acetamidosulfenylation of alkenes [12], among others [13][14][15]. Sulfur-containing compounds are important intermediates in organic synthesis, being able to act as an electrophile or nucleophile in many organic transformations [16][17][18]. Still, many of them are pharmacologically active

• ) and herbicidal applications (fluthiacet-methyl) [37][38]. In this sense, the development of efficient methodologies for the synthesis of sulfur-containing carbonyl compounds employing cheap, stable, nontoxic, easy-to-prepare, and easy-to-handle starting materials is crucial in contemporary organic

• synthesis and medicinal chemistry. In the last years, different methods have been developed to prepare these classes of molecules, which includes the reaction of alkynes [39][40][41][42][43] as well as α-halogenated [44][45] and α-diazo carbonyl compounds [46][47][48][49] with thiols, diorganyl disulfides

1,2,3-Triazoles as leaving groups in S_NAr–Arbuzov reactions: synthesis of C6-phosphonated purine derivatives

• Kārlis-Ēriks Kriķis,
• Irina Novosjolova,
• Anatoly Mishnev and
• Māris Turks

Beilstein J. Org. Chem. 2021, 17, 193–202, doi:10.3762/bjoc.17.19

• Karlis-Eriks Krikis Irina Novosjolova Anatoly Mishnev Maris Turks Faculty of Materials Science and Applied Chemistry, Riga Technical University, P. Valdena Str. 3, LV-1048 Riga, Latvia Latvian Institute of Organic Synthesis, Aizkraukles Str. 21, LV-1006, Riga, Latvia 10.3762/bjoc.17.19 Abstract A

Synthesis, crystal structures and properties of carbazole-based [6]helicenes fused with an azine ring

• Daria I. Tonkoglazova,
• Anna V. Gulevskaya,
• Konstantin A. Chistyakov and
• Olga I. Askalepova

Beilstein J. Org. Chem. 2021, 17, 11–21, doi:10.3762/bjoc.17.2

• Daria I. Tonkoglazova Anna V. Gulevskaya Konstantin A. Chistyakov Olga I. Askalepova Department of Chemistry, Southern Federal University, Zorge str., 7, Rostov-on-Don 344090, Russian Federation I. Ya. Postovsky Institute of Organic Synthesis, Ural Branch of the Russian Academy of Sciences, S

Deoxyfluorination of acyl fluorides to trifluoromethyl compounds by FLUOLEAD^®/Olah’s reagent under solvent-free conditions

• Yumeng Liang,
• Akihito Taya,
• Zhengyu Zhao,
• Norimichi Saito and
• Norio Shibata

Beilstein J. Org. Chem. 2020, 16, 3052–3058, doi:10.3762/bjoc.16.254

• afforded the desired products smoothly in good to high yield in solvent-free conditions. An extension of this deoxyfluorination strategy to drug-like molecules was demonstrated to show the usefulness of this transformation. The present protocol also expands the utility of FLUOLEAD® in organic synthesis

Regioselective synthesis of heterocyclic N-sulfonyl amidines from heteroaromatic thioamides and sulfonyl azides

• Vladimir Ilkin,
• Vera Berseneva,
• Tetyana Beryozkina,
• Tatiana Glukhareva,
• Lidia Dianova,
• Wim Dehaen,
• Eugenia Seliverstova and
• Vasiliy Bakulev

Beilstein J. Org. Chem. 2020, 16, 2937–2947, doi:10.3762/bjoc.16.243

• interesting building blocks in organic synthesis [17][18][19][20] (Figure 1). An N-sulfonyl amidine was recently found to be a key group in acid–base-induced rearrangements of 1,2,3-triazoles and thiadiazoles [22]. A variety of methods have been developed for the synthesis of N-sulfonyl amidines. The most

• amidines of azolyl and pyridine carboxylic acids. The most promising aspect for organic synthesis and green chemistry is a solvent-free process which was successfully applied to prepare sulfonyl amidines containing pyridine and isoxazolyl rings and 1-alkyl-1,2,3-triazole-4-N-sulfonylamidino-1,2,3-triazoles

A novel and robust heterogeneous Cu catalyst using modified lignosulfonate as support for the synthesis of nitrogen-containing heterocycles

• Bingbing Lai,
• Meng Ye,
• Ping Liu,
• Minghao Li,
• Rongxian Bai and
• Yanlong Gu

Beilstein J. Org. Chem. 2020, 16, 2888–2902, doi:10.3762/bjoc.16.238

• ; heterogeneous catalyst; immobilized copper catalyst; lignosulfonate; nitrogen-containing heterocycles; solid acid; Introduction Heterogeneous metal catalysts have been continuously receiving considerable attention in the field of organic synthesis owing to the advantages of easy separation and recycling [1][2

Easy access to a carbohydrate-based template for stimuli-responsive surfactants

• Thomas Holmstrøm,
• Daniel Raydan and
• Christian Marcus Pedersen

Beilstein J. Org. Chem. 2020, 16, 2788–2794, doi:10.3762/bjoc.16.229

• reactions in water, thereby giving rise to a greener approach to organic synthesis [2][3]. Furthermore, the micelles act as a mini-reactor in which the reagents exist in a very high concentration, giving cleaner and faster reactions [1]. The larger aggregates, liposomes, have shown great potential as drug