Synthesis of new substituted 7,12-dihydro-6,12-methanodibenzo[c,f]azocine-5-carboxylic acids containing a tetracyclic tetrahydroisoquinoline core structure

• Agnieszka Grajewska,
• Maria Chrzanowska and
• Wiktoria Adamska

Beilstein J. Org. Chem. 2021, 17, 2511–2519, doi:10.3762/bjoc.17.168

• ; cyclization; multicomponent reactions; synthetic methods; tetrahydroisoquinoline; Introduction The tetrahydroisoquinoline moiety is the key structure in large number of natural and synthetic biologically important molecules. Among them, isoquinoline alkaloids constitute a large family of natural products

Recent advances in the tandem annulation of 1,3-enynes to functionalized pyridine and pyrrole derivatives

• Yi Liu,
• Puying Luo,
• Yang Fu,
• Tianxin Hao,
• Xuan Liu,
• Qiuping Ding and
• Yiyuan Peng

Beilstein J. Org. Chem. 2021, 17, 2462–2476, doi:10.3762/bjoc.17.163

• or ligand in organic chemistry [6][7][8][9][10]. Therefore, the development of efficient methods for the synthesis of pyridine derivatives has attracted considerable attention [11][12][13][14]. The industrial synthetic methods of pyridines mainly involve: i) extraction from coal tar; ii) condensation

• the synthesis of five- or six-membered cyclic compounds [54]. Various efficient synthetic methods have been developed for the synthesis of halogenated pyrroles, which are widely presented in many pharmacologically active natural products, bioactive molecules, and organic building blocks. Based on the

Synthesis and investigation on optical and electrochemical properties of 2,4-diaryl-9-chloro-5,6,7,8-tetrahydroacridines

• Najeh Tka,
• Mohamed Adnene Hadj Ayed,
• Mourad Ben Braiek,
• Mahjoub Jabli and
• Peter Langer

Beilstein J. Org. Chem. 2021, 17, 2450–2461, doi:10.3762/bjoc.17.162

• their optoelectronic properties, the search for new candidates is of ongoing interest. Recently, considerable attention has been given to acridines in our laboratory and we developed new synthetic methods for dibenzoacridines and acridones based on Pd-catalyzed cross-coupling reactions [55][56]. More

Allylic alcohols and amines by carbenoid eliminative cross-coupling using epoxides or aziridines

• Matthew J. Fleming and
• David M. Hodgson

Beilstein J. Org. Chem. 2021, 17, 2385–2389, doi:10.3762/bjoc.17.155

• alkoxide. Keywords: alkenes; aziridines; epoxides; lithiation; synthetic methods; Introduction Methods for the convergent generation of alkenes can be of significant utility in organic synthesis [1]. A relatively under-examined approach is through the interaction of two carbenoids [2]. Dimerisation of

Catalyzed and uncatalyzed procedures for the syntheses of isomeric covalent multi-indolyl hetero non-metallides: an account

• Ranadeep Talukdar

Beilstein J. Org. Chem. 2021, 17, 2102–2122, doi:10.3762/bjoc.17.137

• in the spotlight of anticancer research recently. In line with this high importance associated with the molecules of current topic, i.e., more than one indole molecule flanked by a central atom, conglomeration of the available synthetic methods will have a high scientific value. This review will give

Recent advances in the syntheses of anthracene derivatives

• Giovanni S. Baviera and
• Paulo M. Donate

Beilstein J. Org. Chem. 2021, 17, 2028–2050, doi:10.3762/bjoc.17.131

• , anthracene derivatives display useful biological activities; for instance, the anthraquinone derivatives 5 and 6 exert antimicrobial and anti-inflammatory activity, respectively (Figure 1) [15][16]. Despite some difficulties and limitations, a number of synthetic methods for preparing anthracene derivatives

• syntheses of anthracene derivatives, the considerable number of methodologies reported in recent years is truly surprising. Due to the wide applicability of anthracene and anthraquinone derivatives in important fields of science, the development of new synthetic methods is likely to increase. We hope that

• sequential modifications [30], photocyclization of divinylterphenyl derivatives [31], tandem radical cyclization of (Z,Z)-1,4-bis(2-iodostyryl)benzene derivatives [32], and ring-closing olefin metathesis of tetravinylterphenyls [33] as the best-known synthetic routes. Herein, we have classified the synthetic

Progress and challenges in the synthesis of sequence controlled polysaccharides

• Giulio Fittolani,
• Theodore Tyrikos-Ergas,
• Denisa Vargová,
• Manishkumar A. Chaube and
• Martina Delbianco

Beilstein J. Org. Chem. 2021, 17, 1981–2025, doi:10.3762/bjoc.17.129

Asymmetric organocatalyzed synthesis of coumarin derivatives

• Natália M. Moreira,
• Lorena S. R. Martelli and
• Arlene G. Corrêa

Beilstein J. Org. Chem. 2021, 17, 1952–1980, doi:10.3762/bjoc.17.128

• and synthetic chemistry. Compounds of this class have shown important activities, such as anticancer and antiparasitic, besides the commercially available drugs. These properties led to the development of efficient and greener synthetic methods to achieve the 2H-chromen-2-one core. In this context

On the application of 3d metals for C–H activation toward bioactive compounds: The key step for the synthesis of silver bullets

• Renato L. Carvalho,
• Amanda S. de Miranda,
• Mateus P. Nunes,
• Roberto S. Gomes,
• Guilherme A. M. Jardim and
• Eufrânio N. da Silva Júnior

Beilstein J. Org. Chem. 2021, 17, 1849–1938, doi:10.3762/bjoc.17.126

• -containing substrates, and its high efficiency makes it an excellent methodology for late-stage modifications (Scheme 20D). Biaryl structures are present in several important drugs currently commercially available (57, 58, and 59, Scheme 21A) [141] and synthetic methods to achieve the aryl–aryl connection

Development of N-F fluorinating agents and their fluorinations: Historical perspective

• Teruo Umemoto,
• Yuhao Yang and
• Gerald B. Hammond

Beilstein J. Org. Chem. 2021, 17, 1752–1813, doi:10.3762/bjoc.17.123

Cerium-photocatalyzed aerobic oxidation of benzylic alcohols to aldehydes and ketones

• Girish Suresh Yedase,
• Sumit Kumar,
• Jessica Stahl,
• Burkhard König and
• Veera Reddy Yatham

Beilstein J. Org. Chem. 2021, 17, 1727–1732, doi:10.3762/bjoc.17.121

• photocatalysis has emerged as an alternative to the classical conventional synthetic methods to construct carbon–carbon and carbon–heteroatom bonds [34][35][36][37]. As a mild, efficient, and environmentally friendly approach it has the potential to unlock unique reactions that are previously inaccessible under

Cascade intramolecular Prins/Friedel–Crafts cyclization for the synthesis of 4-aryltetralin-2-ols and 5-aryltetrahydro-5H-benzo[7]annulen-7-ols

• Jie Zheng,
• Shuyu Meng and
• Quanrui Wang

Beilstein J. Org. Chem. 2021, 17, 1481–1489, doi:10.3762/bjoc.17.104

• therapeutic for psychoses, addiction, and other neuropsychiatric disorders. Although 4-substitituted tetralin-2-ols and derivatives with significant pharmaceutical activities have been identified, only a limited number of synthetic methods is documented in the literature (Scheme 1) [7][8][9]. Moreover, these

• methods generally require multiple steps, proceed in low overall yields, and have a limited ability for structural modifications to prepare analogues with new substitution patterns for enhancing activities. Consequently, it is highly desirable to develop new synthetic methods that provide efficient access

Iodine-catalyzed electrophilic substitution of indoles: Synthesis of (un)symmetrical diindolylmethanes with a quaternary carbon center

• Thanigaimalai Pillaiyar,
• Masoud Sedaghati,
• Andhika B. Mahardhika,
• Lukas L. Wendt and
• Christa E. Müller

Beilstein J. Org. Chem. 2021, 17, 1464–1475, doi:10.3762/bjoc.17.102

• ]. However, synthetic methods for efficient synthesis of unsymmetrical 3,3'-DIMs with a quaternary carbon center, including trifluoromethyl-substituted 3,3'-DIMs, are still rare. Sasaki et al. reported the reaction of trifluoromethyl(indolyl)phenylmethanols with indoles in the presence of trifluoroacetic

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

• activity within the field today (Figure 2). Flow chemistry Batch-based synthetic methods have enabled a wide variety of transformations to be performed at industrial scales, however, the implementation of flow-based protocols often lends itself to the creation of superior synthetic systems. Improved

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

• ligands [52][53][54][55] and as chiral auxiliaries [56]. The most widely used synthetic methods to form the aziridine ring [57][58][59][60][61] include intramolecular cyclizations in amines bearing potential leaving groups. Stereoselective syntheses of aziridines have been successfully carried out by

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

• for their synthesis, work-up, and purification. In this context, the aim of the next part of this review is to propose a generalized and comparative overview of the synthetic methods to access this particular scaffold. We chose to sort the synthetic routes by reaction types, from the most general and

• examples have also been reported for the addition of amines to arylcyanoguanidines (vide infra). Fusion of cyanoguanidine and amine hydrochlorides: The direct fusion of a mixture of cyanoguanidine and amine salts was one of the earliest synthetic methods of biguanides, described for the first time in 1892

Prins cyclization-mediated stereoselective synthesis of tetrahydropyrans and dihydropyrans: an inspection of twenty years

• Asha Budakoti,
• Pradip Kumar Mondal,
• Prachi Verma and
• Jagadish Khamrai

Beilstein J. Org. Chem. 2021, 17, 932–963, doi:10.3762/bjoc.17.77

• , and pharmaceutical agents. These structural motifs are frequently used as synthons and as key intermediates for natural product synthesis. Therefore, the development of stereoselective synthetic methods for the substituted THP subunit has long been the area of fundamental research in organic chemistry

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

• derivatives having various substituents on the ethylene moiety. In particular, synthetic methods that do not use metal catalysts and reagents are expected to be very effective in manufacturing precision materials and pharmaceuticals [32][33][34][35][36][37]. To develop metal-free methods for the synthesis of

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

• biological activities [1][2][3][16][17][18][19][20][21][22][23][24][25][26]. However, only a limited number of synthetic methods are available for the synthesis of seven- [27][28], eight- [29][30][31][32][33][34][35][36][37][38], and nine- [35] membered aminocyclitols. Therefore, we were inspired to work on

[2 + 1] Cycloaddition reactions of fullerene C₆₀ based on diazo compounds

• Yuliya N. Biglova

Beilstein J. Org. Chem. 2021, 17, 630–670, doi:10.3762/bjoc.17.55

• processes, among which reactions leading to methanofullerenes are widely used. Two main synthetic methods for the production of methanofullerenes can be distinguished (Scheme 1): nucleophilic cyclopropanation with stabilized carbanions that occurs by the addition–cleavage mechanism – the Bingel reaction (I

Designed whole-cell-catalysis-assisted synthesis of 9,11-secosterols

• Marek Kõllo,
• Marje Kasari,
• Villu Kasari,
• Tõnis Pehk,
• Ivar Järving,
• Margus Lopp,
• Arvi Jõers and
• Tõnis Kanger

Beilstein J. Org. Chem. 2021, 17, 581–588, doi:10.3762/bjoc.17.52

• toxic oxidants. Keywords: chemoenzymatic synthesis; cortisol; hydroxylation; secosterol; whole-cell catalysis; Introduction Developments in the chemistry of steroids have stimulated extensive research interest in the exploration of new synthetic methods since the 1960s. Advances in synthetic biology

• synthetic methods for secosteroids is wide. However, usually these are multistep sequences exploiting toxic oxidants. Marine invertebrates are a rich source of oxidated and highly functionalized steroidal metabolites, including secosteroids. Since the first isolation of 9,11-secosterol from

Breakdown of 3-(allylsulfonio)propanoates in bacteria from the Roseobacter group yields garlic oil constituents

• Anuj Kumar Chhalodia and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2021, 17, 569–580, doi:10.3762/bjoc.17.51

• °C min−1 to 320 °C and operated in the splitless mode (60 s valve time); carrier gas (He): 1.2 mL min−1. The retention indices were determined from n-alkane standards (C8–C32) [42]. General synthetic methods All chemicals were purchased from TCI (Deutschland) or Sigma-Aldrich Chemie (Germany), and

Amino- and polyaminophthalazin-1(2H)-ones: synthesis, coordination properties, and biological activity

• Zbigniew Malinowski,
• Emilia Fornal,
• Agata Sumara,
• Renata Kontek,
• Karol Bukowski,
• Beata Pasternak,
• Dariusz Sroczyński,
• Joachim Kusz,
• Magdalena Małecka and
• Monika Nowak

Beilstein J. Org. Chem. 2021, 17, 558–568, doi:10.3762/bjoc.17.50

• phthalazinone derivatives 5 and 6 (Scheme 1, route B). In the literature, the number of reported synthetic methods for 4-aminophthalazin-1(2H)-ones is limited to a few examples and they usually involve two main approaches: 1) the application of multicomponent reactions starting from, e.g., the available o

Synthetic strategies of phosphonodepsipeptides

• Jiaxi Xu

Beilstein J. Org. Chem. 2021, 17, 461–484, doi:10.3762/bjoc.17.41

• the phosphinylation of hydroxy esters 2 with N-protected aminoalkylphosphonochloridites 9 followed by oxidation (method V) (Figure 2). This review focuses on the synthetic methods of phosphonodepsipeptides and phosphonodepsipeptides with C-1-hydroxyalkylphosphonic acids, excluding peptides with side

• , haptens for the production of antibodies, biological agents, and prodrugs. Various synthetic methods of phosphonodepsipeptides have been developed, including the phosphonylation of hydroxy esters with phosphonochloridates or with phosphonic monoesters in the presence of coupling reagents, the alkylation

• synthetic methods, the multicomponent Mannich-type condensation strategy shows a high efficiency, convergent feature, and product diversity. It can be expected that the convergent multicomponent condensation synthetic strategy will show wide applications in the preparation of biologically active

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

• material sciences [14][15][16][17]. In this context, deciphering the impact that can be exerted by the trifluoromethyl group on a cation and the associated consequences when facing the challenge of developing innovative synthetic methods are the subjects of this review. Review Quantitative parameters