Methodologies for the synthesis of quaternary carbon centers via hydroalkylation of unactivated olefins: twenty years of advances

• Thiago S. Silva and
• Fernando Coelho

Beilstein J. Org. Chem. 2021, 17, 1565–1590, doi:10.3762/bjoc.17.112

• activation. The use of metals in which the protodemetalation step of the σ-alkylmetal complex occurs preferentially to the β-hydride elimination arose as an alternative for the development of new methodologies. During the early 2000s, several synthetic methodologies flourished that employed gold catalysis to

Double-headed nucleosides: Synthesis and applications

• Vineet Verma,
• Jyotirmoy Maity,
• Vipin K. Maikhuri,
• Ritika Sharma,
• Himal K. Ganguly and
• Ashok K. Prasad

Beilstein J. Org. Chem. 2021, 17, 1392–1439, doi:10.3762/bjoc.17.98

• pentofuranosyl sugar moiety. Various synthetic methodologies have been developed for the introduction of the additional nucleobase/heterocyclic system directly or via a linker at the C-2′/C-3′/C-4′/C-5′ position of the pentofuranosyl moieties. We have categorized the double-headed furanosyl-nucleosides depending

• , Bose Institute, P1/12 CIT Scheme VIIM, Kolkata-700 054, India 10.3762/bjoc.17.98 Abstract Double-headed nucleoside monomers have immense applications for studying secondary nucleic acid structures. They are also well-known as antimicrobial agents. This review article accounts for the synthetic

• methodologies and the biological applications of double-headed nucleosides. Keywords: acyclic double-headed nucleosides; bicyclic double-headed nucleosides; furanosyl double-headed nucleosides; modified nucleosides; pyranosyl double-headed nucleosides; Introduction Nucleosides are the constructional subunits

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

• metathesis, Ullmann-type coupling, Clauson–Kaas, and Van Leusen reactions as crucial transformations. Synthetic Strategy Basically, our endeavor toward the synthesis of truxene-based systems has been rooted in the development of new synthetic methodologies to assemble diverse polycyclic as well as

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

• . Asymmetric synthesis of pyrrolidines The pyrrolidine ring is more represented within natural products than the 3- and 4-membered nitrogen-containing heterocycles. This molecular array is also found in drugs and other biologically active molecules. For this reason, there are numerous examples of synthetic

• methodologies for these compounds in the literature. In most cases, the pyrrolidine ring is formed from an amine with a hydrocarbon chain that also carries a functional group at the appropriate distance that allows the cyclization process to take place. In the case of substituted pyrrolidines, the

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

• critical overview of the synthetic accesses to biguanide compounds, as well as their comparative advantages and limitations. It also underlines the need of developing new synthetic methodologies to reach a wider variety of biguanides and to overcome the underrepresentation of these compounds. Keywords

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

• inhibitors of α-glycosidases [11][19]. Recent reviews report on the latest synthetic methodologies for aminocyclitols and related compounds [1][2][3][16]. Many methods have been previously reported for the synthesis of aminocyclitols containing five- and six-membered rings, along with their diverse

A new and efficient methodology for olefin epoxidation catalyzed by supported cobalt nanoparticles

• Lucía Rossi-Fernández,
• Viviana Dorn and
• Gabriel Radivoy

Beilstein J. Org. Chem. 2021, 17, 519–526, doi:10.3762/bjoc.17.46

• heterogeneous catalysts [27] that are wide in substrate scope, active enough and highly selective. As part of our continuing interest in the development of new synthetic methodologies based on the use of catalysis by non-noble transition metal nanoparticles (MNPs) for their application in a wide range of

1,2,3-Triazoles as leaving groups: S_NAr reactions of 2,6-bistriazolylpurines with O- and C-nucleophiles

• Dace Cīrule,
• Irina Novosjolova,
• Ērika Bizdēna and
• Māris Turks

Beilstein J. Org. Chem. 2021, 17, 410–419, doi:10.3762/bjoc.17.37

• ][3][4][5][6]. They are often used as antiviral, anticancer and antibacterial agents. Such intensive medicinal chemistry applications demand for constant development of novel synthetic methodologies. Frequently, the purine structure is modified in SNAr reactions with N- [7][8][9][10][11] and S

A sustainable strategy for the straightforward preparation of 2H-azirines and highly functionalized NH-aziridines from vinyl azides using a single solvent flow-batch approach

• Michael Andresini,
• Leonardo Degannaro and
• Renzo Luisi

Beilstein J. Org. Chem. 2021, 17, 203–209, doi:10.3762/bjoc.17.20

• risks [6]. Recently, a variety of sustainable solvents has been therefore identified, and their use have been combined with those of enabling technologies. In this scenario, the development of continuous flow synthetic methodologies has found its fortune in the past two decades [7][8][9]. Several

Progress in the total synthesis of inthomycins

• Bidyut Kumar Senapati

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

• present review provides a systematic summary of synthetic strategies for the synthesis of inthomycins and their analogues over the period of 1999 to present. Rewiew Synthesis Undoubtedly, the unique skeleton of inthomycins has acted as an inspiration for the development of new synthetic methodologies

Recent progress in the synthesis of homotropane alkaloids adaline, euphococcinine and N-methyleuphococcinine

• Dimas J. P. Lima,
• Antonio E. G. Santana,
• Michael A. Birkett and
• Ricardo S. Porto

Beilstein J. Org. Chem. 2021, 17, 28–41, doi:10.3762/bjoc.17.4

• provide enantiomerically pure alkaloids. Therefore, homotropane-based compounds continue to attract the attention of researchers involved in the progress for new synthetic methodologies to reproduce these natural products and synthesize their analogs, improving existing methods. Homotropane

An atom-economical addition of methyl azaarenes with aromatic aldehydes via benzylic C(sp³)–H bond functionalization under solvent- and catalyst-free conditions

• Divya Rohini Yennamaneni,
• Vasu Amrutham,
• Krishna Sai Gajula,
• Rammurthy Banothu,
• Murali Boosa and
• Narender Nama

Beilstein J. Org. Chem. 2020, 16, 3093–3103, doi:10.3762/bjoc.16.259

• reevaluated. Therefore, alternatives with environmentally benign reagents are much in focus. Correspondingly, considering the exemplar shift from conventional synthetic methodologies towards green chemistry, there have been some alternatives or replacements of toxic catalysts and hazardous solvents in

Synthesis of imidazo[1,5-a]pyridines via cyclocondensation of 2-(aminomethyl)pyridines with electrophilically activated nitroalkanes

• Dmitrii A. Aksenov,
• Nikolai A. Arutiunov,
• Vladimir V. Maliuga,
• Alexander V. Aksenov and
• Michael Rubin

Beilstein J. Org. Chem. 2020, 16, 2903–2910, doi:10.3762/bjoc.16.239

• Within the last few years, we have developed and implemented a number of novel synthetic methodologies in our laboratories, involving acid-mediated cascade transformations of nitroalkenes and nitroalkanes, which target materials science and medicinal chemistry applications. It was demonstrated that upon

Synthesis of novel fluorinated building blocks via halofluorination and related reactions

• Attila Márió Remete,
• Tamás T. Novák,
• Melinda Nonn,
• Matti Haukka,
• Ferenc Fülöp and
• Loránd Kiss

Beilstein J. Org. Chem. 2020, 16, 2562–2575, doi:10.3762/bjoc.16.208

• cyclic olefins, such as diesters, imides, and lactams with varied functionalization patterns and different structural architectures is described. The synthetic methodologies were based on electrophilic activation through halonium ions of the ring olefin bonds, followed by nucleophilic fluorination with

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

• most profound influence [10][11][12]. Regarding the development of new synthetic methodologies for the preparation of such molecules, these can be divided in two main categories: fluorination reactions [13][14][15][16] and the use of fluorinated building blocks [17]. The difference between them is that

Azidophosphonium salt-directed chemoselective synthesis of (E)/(Z)-cinnamyl-1H-triazoles and regiospecific access to bromomethylcoumarins from Morita–Baylis–Hillman adducts

• Soundararajan Karthikeyan,
• Radha Krishnan Shobana,
• Kamarajapurathu Raju Subimol,
• J. Helen Ratna Monica and
• Ayyanoth Karthik Krishna Kumar

Beilstein J. Org. Chem. 2020, 16, 1579–1587, doi:10.3762/bjoc.16.130

• for the synthesis of 3-(bromomethyl)coumarins. Literature-reported cycloaddition reactions of MBH acetates involving azides and alkynes [24][25][26][27][28]. Synthetic methodologies for triazolations of MBH adducts. a) Literature-reported indirect triazolation of MBH adducts [32][33]. b) This work

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

• molecules using copper-based fluorinated reagents will be given. Keywords: copper; difluoromethylation; fluorinated reagents; fluorine chemistry; synthetic methodologies; Introduction In a society in which fluorinated molecules are playing a pivotal role in pharmaceutical and agrochemical industries as

Recent applications of porphyrins as photocatalysts in organic synthesis: batch and continuous flow approaches

• Rodrigo Costa e Silva,
• Luely Oliveira da Silva,
• Aloisio de Andrade Bartolomeu,
• Timothy John Brocksom and
• Kleber Thiago de Oliveira

Beilstein J. Org. Chem. 2020, 16, 917–955, doi:10.3762/bjoc.16.83

• such as tetrakis(pentafluorophenyl)porphyrin (TPFPP) is more efficient in an oxidative quenching compared to an electron-rich (e.g., TPP) remained to be elucidated. In this regard, our research group has contributed in the last 10 years with new porphyrin/chlorin synthetic methodologies, and

Efficient method for propargylation of aldehydes promoted by allenylboron compounds under microwave irradiation

• Jucleiton J. R. Freitas,
• Queila P. S. B. Freitas,
• Silvia R. C. P. Andrade,
• Juliano C. R. Freitas,
• Roberta A. Oliveira and
• Paulo H. Menezes

Beilstein J. Org. Chem. 2020, 16, 168–174, doi:10.3762/bjoc.16.19

• great care on a case-by-case basis. Even so, the search for safer alternatives to current synthetic methodologies avoiding the use of moisture/air-sensitive organometallics and, more important, the development of solvent-free protocols are in accordance with the concept of environmental impact factor (E

Mechanochemistry of supramolecules

• Anima Bose and
• Prasenjit Mal

Beilstein J. Org. Chem. 2019, 15, 881–900, doi:10.3762/bjoc.15.86

• conditions through covalent approaches. By using common synthetic methodologies chemists are able to proficiently synthesize a variety of both natural and unnatural molecular scaffolds [4][5][6]. The era of supramolecular chemistry began with the introduction of coordination theory by Alfred Werner in 1893

Synthesis of nonracemic hydroxyglutamic acids

• Dorota G. Piotrowska,
• Iwona E. Głowacka,
• Andrzej E. Wróblewski and
• Liwia Lubowiecka

Beilstein J. Org. Chem. 2019, 15, 236–255, doi:10.3762/bjoc.15.22

• ) also appeared attractive providing two or three predefined stereogenic centers. In more sophisticated approaches application of chiral auxiliaries allowed to generate vicinal or 1,3-aminoalcohol units of the required stereochemistries. Currently available synthetic methodologies towards hydroxyglutamic

• discussed which allow, for example, to differentiate between α and ω carboxy groups. Although syntheses of particular enantiomers of hydroxyglutamic acids look to be optimal, e.g., (2S,4S)-3 or (2S,4R)-3 via hydroxylation of the protected glutamic or pyroglutamic acids, synthetic methodologies to the other

Calixazulenes: azulene-based calixarene analogues – an overview and recent supramolecular complexation studies

• Paris E. Georghiou,
• Shofiur Rahman,
• Abdullah Alodhayb,
• Hidetaka Nishimura,
• Jaehyun Lee,
• Atsushi Wakamiya and
• Lawrence T. Scott

Beilstein J. Org. Chem. 2018, 14, 2488–2494, doi:10.3762/bjoc.14.225

• result of Gutsche’s synthetic methodologies many researchers have been able to employ these calix[n]arenes and modified derivatives thereof in a great variety of ingenious applications. These applications have included a myriad of synthetic modifications to both, or either, of their upper and lower rims

Applications of organocatalysed visible-light photoredox reactions for medicinal chemistry

• Michael K. Bogdos,
• Emmanuel Pinard and
• John A. Murphy

Beilstein J. Org. Chem. 2018, 14, 2035–2064, doi:10.3762/bjoc.14.179

• much milder route to these heterocycles than traditional synthetic methodologies, which typically use harsh conditions. Semicarbazones are readily synthesised from the corresponding aldehydes, so these starting materials are easily accessible. The yields are very good to excellent (86–96%), while the

Recent advances in synthetic approaches for medicinal chemistry of C-nucleosides

• Kartik Temburnikar and
• Katherine L. Seley-Radtke

Beilstein J. Org. Chem. 2018, 14, 772–785, doi:10.3762/bjoc.14.65

• ]. Pseudouridine is a naturally occurring C-nucleoside that was first discovered in the 1950s [45][46][47][50]. Subsequently, many more C-nucleosides were discovered and their medicinal properties evaluated (Figure 4) [18][29][37][45][46][47][48][49][50][60][61][62]. Due to advances in synthetic methodologies over

Synthesis of fluoro-functionalized diaryl-λ³-iodonium salts and their cytotoxicity against human lymphoma U937 cells

• Prajwalita Das,
• Etsuko Tokunaga,
• Hidehiko Akiyama,
• Hiroki Doi,
• Norimichi Saito and
• Norio Shibata

Beilstein J. Org. Chem. 2018, 14, 364–372, doi:10.3762/bjoc.14.24

• structures of various pharmaceuticals, agrochemicals and coatings contain fluorine or fluorinated functional groups [4][5][6][7][8][9]. Therefore, the development of efficient synthetic methodologies for organofluorine compounds has gained much attention [10][11][12][13][14][15]. Our research group has been