Multicomponent reactions: A simple and efficient route to heterocyclic phosphonates

• Mohammad Haji

Beilstein J. Org. Chem. 2016, 12, 1269–1301, doi:10.3762/bjoc.12.121

• . Some of these post-MCR transformations are: intramolecular cycloaddition reactions, Knoevenagel condensations, metathesis reactions, aza-Wittig reactions, Mitsunobu reactions, etc. [21]. Up to now, two review articles have been reported on azaheterocyclic phosphonates [22][23], but no overview article

• about the multicomponent synthesis of phosphono-substituted heterocycles has been reported so far. This review focuses on general multicomponent reactions as well as on modified MCR towards heterocyclic phosphonates. It is organized by the reaction types and covers literature published up to September

• irradiation. Thus, the development of novel MCR based on phosphorous reagents would allow the synthesis of macrocyclic and medium or large-sized heterocyclic systems, substances which are currently underrepresented in the literature. Further, the design of new biocompatible scaffolds such as β-lactams and

Multicomponent versus domino reactions: One-pot free-radical synthesis of β-amino-ethers and β-amino-alcohols

• Bianca Rossi,
• Nadia Pastori,
• Simona Prosperini and
• Carlo Punta

Beilstein J. Org. Chem. 2015, 11, 66–73, doi:10.3762/bjoc.11.10

• approach. In fact, our procedure requires neither the preformation of imines nor anhydrous media, due to the coordinating effect of titanium salts, which promote the one-pot synthesis of amino derivatives according to a classical MCR. The basic approach consists of the simple mixing of an aniline, an

Synthesis of antibacterial 1,3-diyne-linked peptoids from an Ugi-4CR/Glaser coupling approach

• Martin C. N. Brauer,
• Ricardo A. W. Neves Filho,
• Bernhard Westermann,
• Ramona Heinke and
• Ludger A. Wessjohann

Beilstein J. Org. Chem. 2015, 11, 25–30, doi:10.3762/bjoc.11.4

• . In addition, HPLC analyses revealed that an adjacent stereocenter (Table 1, entry 8, 7h/8h) does not racemize under the reaction conditions of both the MCR and the Glaser coupling. Due to the high selectivity and high conversions found in the Glaser coupling step, our attention turned toward the

• activity of the active ligand moieties. Conclusion In summary, a reliable sequential U-4CR/Glaser coupling approach towards the synthesis of 1,3-diyne-linked peptoids was developed. The strategy resulted in a library consisting of ten homodimers in good yields. The post-MCR copper-catalysed homocoupling

The Shono-type electroorganic oxidation of unfunctionalised amides. Carbon–carbon bond formation via electrogenerated N-acyliminium ions

• Alan M. Jones and
• Craig E. Banks

Beilstein J. Org. Chem. 2014, 10, 3056–3072, doi:10.3762/bjoc.10.323

• is attached either to the carbamate or amide (Figure 5) [69][70][71] (using a platinum anode and tungsten cathode electrochemical set-up) [69] or the use of Cu-PyBox chiral ligand systems [72]. The cation pool method can be adapted to a multicomponent reaction (MCR) when an N-acyliminium ion is

Facile synthesis of 1H-imidazo[1,2-b]pyrazoles via a sequential one-pot synthetic approach

• András Demjén,
• Márió Gyuris,
• János Wölfling,
• László G. Puskás and
• Iván Kanizsai

Beilstein J. Org. Chem. 2014, 10, 2338–2344, doi:10.3762/bjoc.10.243

• -withdrawing substituents as in 2e–g resulted in decreased yields. α-Methylcinnamaldehyde (2i) as an uncommon isocyanide-based MCR component was successfully subjected to the GBB reaction, leading to the formation of the corresponding bicycles 38–41 in yields of 26–67%. All the reactions except those based on

Synthesis of α-amino amidines through molecular iodine-catalyzed three-component coupling of isocyanides, aldehydes and amines

• Praveen Reddy Adiyala,
• D. Chandrasekhar,
• Jeevak Sopanrao Kapure,
• Chada Narsimha Reddy and
• Ram Awatar Maurya

Beilstein J. Org. Chem. 2014, 10, 2065–2070, doi:10.3762/bjoc.10.214

• part of our ongoing interest towards the synthesis of new molecular libraries [21][22][23][24], we were interested in developing a one-pot MCR strategy for the synthesis of amidines. Results and Discussion To check the feasibility of the iodine-catalyzed amidine synthesis through the modified Ugi

Synthesis of trifluoromethyl-substituted pyrazolo[4,3-c]pyridines – sequential versus multicomponent reaction approach

• Barbara Palka,
• Angela Di Capua,
• Maurizio Anzini,
• Gyté Vilkauskaité,
• Algirdas Šačkus and
• Wolfgang Holzer

Beilstein J. Org. Chem. 2014, 10, 1759–1764, doi:10.3762/bjoc.10.183

• afforded the corresponding pyrazolo[4,3-c]pyridine 5-oxides 7a–c by a regioselective 6-endo-dig cyclisation [30] in high yields. Moreover, we tested an alternative approach to access compounds 7 through multicomponent reactions (MCR). Attempts to react chloroaldehyde 2 with hydroxylamine hydrochloride and

Multicomponent reactions in nucleoside chemistry

• Mariola Koszytkowska-Stawińska and
• Włodzimierz Buchowicz

Beilstein J. Org. Chem. 2014, 10, 1706–1732, doi:10.3762/bjoc.10.179

• employment of MCRs in the synthesis of nucleoside analogs. The references were selected in accordance with the definition of a MCR given by Ugi et al.: “a multicomponent reaction comprises reactions with more than two starting materials participating in the reaction and, at the same time, the atoms of these

• educts contribute the majority of the novel skeleton of the product” [44]. In this review, we understand educts as compounds that contribute carbon atoms to the MCR product [45]. By the analogy to nucleosides included in the DNA/RNA nucleic acids, this review is limited to MCRs involving furanosyl

• carbon atom. Conclusion In this comprehensive review application of multicomponent reactions (MCRs) in nucleoside chemistry has been presented. In recent years, growing interest in the construction of novel nucleoside scaffolds by MCR has been observed. This conclusion is supported by the fact that 23

Microwave-assisted Cu(I)-catalyzed, three-component synthesis of 2-(4-((1-phenyl-1H-1,2,3-triazol-4-yl)methoxy)phenyl)-1H-benzo[d]imidazoles

• Yogesh Kumar,
• Vijay Bahadur,
• Anil K. Singh,
• Virinder S. Parmar,
• Erik V. Van der Eycken and
• Brajendra K. Singh

Beilstein J. Org. Chem. 2014, 10, 1413–1420, doi:10.3762/bjoc.10.145

• (Scheme 1, path C) as a multicomponent reaction (MCR). The utility and importance of MCRs have been recognized by chemists [20][21][22][23]. Several MCRs are now well-established reactions, such as Ugi [24], Passerini [25], Van Leusen [26], Strecker [27], Hantzsch [28], and Biginelli [29][30][31]. However

• % yield upon stirring at rt and microwave irradiation, respectively (path B). However, in the MCR approach (Scheme 1, path C) the desired product was obtained in a good yield. The reaction proceeded smoothly in the presence of CuSO4.5H2O and D-glucose under microwave irradiation for 15 min and gave the

• desired compound in 80% yield. Surprisingly, under conventional heating with this MCR approach no product formation was observed, even after an extended period of time (24 h) with heating under reflux . In order to optimize the reaction conditions for this protocol, we screened several organic solvents

Isocyanide-based multicomponent reactions towards cyclic constrained peptidomimetics

• Gijs Koopmanschap,
• Eelco Ruijter and
• Romano V.A. Orru

Beilstein J. Org. Chem. 2014, 10, 544–598, doi:10.3762/bjoc.10.50

• cyclic constrained peptidomimetics, the acyclic products have to be cyclized via additional cyclization strategies. This is possible via incorporation of bifunctional substrates into the initial IMCR. Examples of such bifunctional groups are N-protected amino acids, convertible isocyanides or MCR

• . Besides saving time and reagents, another major advantage of these reactions is the ability to combine commercially available or readily accessible starting materials with a variety of functionalities in one-step. Further, MCR-based strategies can cover a broader range of chemical space because a large

• . the incorporation of bifunctional substrates or by activation of functionalized substrates in the initial MCR [19]. The Passerini reaction The first isocyanide-based MCR was described by Mario Passerini in 1921 and named after him. The Passerini reaction is a three-component reaction (3-CR) and

Silver and gold-catalyzed multicomponent reactions

• Giorgio Abbiati and
• Elisabetta Rossi

Beilstein J. Org. Chem. 2014, 10, 481–513, doi:10.3762/bjoc.10.46

• recently, silver–NHC complexes were found to be valuable catalysts for this MCR. Their first application was reported by Wang and co-workers in 2008 [12], who developed a polystyrene-supported NHC–Ag(I) complex as an efficient catalyst for the A3-coupling under solvent-free conditions, at room temperature

• without a significant loss of its catalytic activity. Similar PS–NHC–silver complexes were recently prepared via click-chemistry, and their aptitude to catalyze A3-coupling was verified [13]. The suitability of NHC–Ag(I) complexes as catalysts for A3-coupling MCR was confirmed, and independently developed

• an effective KA2-MCR, that is, the substitution of aldehyde partners with less reactive ketones. This issue was partially solved by Ji and co-workers, who found with AuBr3 (4 mol %), no-solvent and 60 °C the best conditions to react alkyl ketones, secondary amines and aryl/alkylacetylenes to give the

Diversity-oriented synthesis of dihydrobenzoxazepinones by coupling the Ugi multicomponent reaction with a Mitsunobu cyclization

• Lisa Moni,
• Luca Banfi,
• Andrea Basso,
• Alice Brambilla and
• Renata Riva

Beilstein J. Org. Chem. 2014, 10, 209–212, doi:10.3762/bjoc.10.16

• reactions [2], especially the intramolecular Mitsunobu reaction of alcohols with phenols or sulfonamides. By exploiting a single post-MCR transformation (the Mitsunobu reaction) it is possible to obtain several diverse heterocyclic scaffolds by installing the two additional groups in any of the four

Multicomponent reactions II

• Thomas J. J. Müller

Beilstein J. Org. Chem. 2014, 10, 115–116, doi:10.3762/bjoc.10.7

• Thomas J. J. Muller Heinrich-Heine-Universität Düsseldorf, Institut für Makromolekulare Chemie und Organische Chemie, Lehrstuhl für Organische Chemie, Universitätsstr. 1, 40225 Düsseldorf, Germany 10.3762/bjoc.10.7 Keywords: multicomponent; The concept of multicomponent reactions (MCR) [1] has

• addition, a lot of syntheses of heterocycles from the early days are MCR, and these reaction sequences paved the way to a multitude of applications. Moreover, Ugi's groundbreaking developments in isonitrile-based chemistry and his conclusions demonstrated that MCR are not only highly practicable in the

• light of approaching the ideal synthesis [3][4] as one-pot methodologies, but rely on a reactivity based concept [5]. The perpetual generation of reactive functionalities and reactivity is the underlying general principle. Therefore, MCR are intriguing for industrial applications. But they are also

Studies on the interaction of isocyanides with imines: reaction scope and mechanistic variations

• Ouldouz Ghashghaei,
• Consiglia Annamaria Manna,
• Esther Vicente-García,
• Marc Revés and
• Rodolfo Lavilla

Beilstein J. Org. Chem. 2014, 10, 12–17, doi:10.3762/bjoc.10.3

• imines with isocyanides is mainly focused on to the well-known Ugi multicomponent reaction (MCR) [1]. This fundamental process features the participation of a carboxylic acid group which attacks the intermediate nitrilium ion thus leading, after the Mumm rearrangement, to α-amidoamides. However, the

• . Compounds 4 and 5 could not be detected (Scheme 2). When the process was run as a true MCR (mixing the amine, the aldehyde and two equivalents of isocyanide 2a), the adduct 3a was produced in trace amounts and the main product was the α-amino-amidine 4, in good agreement with previous reports [5][6][7][8

An overview of the synthetic routes to the best selling drugs containing 6-membered heterocycles

• Marcus Baumann and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2013, 9, 2265–2319, doi:10.3762/bjoc.9.265

Dipyrazolo[1,5-a:4',3'-c]pyridines – a new heterocyclic system accessed via multicomponent reaction

• Wolfgang Holzer,
• Gytė Vilkauskaitė,
• Eglė Arbačiauskienė and
• Algirdas Šačkus

Beilstein J. Org. Chem. 2012, 8, 2223–2229, doi:10.3762/bjoc.8.251

• to the latter was achieved by a multicomponent reaction (MCR) starting from 5-alkynylpyrazole-4-carbaldehydes. Such MCRs, although being present since the early days of organic chemistry, nowadays attract an increasing interest because of their unmatched synthetic efficiency, which permits the

Features of the behavior of 4-amino-5-carboxamido-1,2,3-triazole in multicomponent heterocyclizations with carbonyl compounds

• Eugene S. Gladkov,
• Katerina A. Gura,
• Svetlana M. Sirko,
• Sergey M. Desenko,
• Ulrich Groth and
• Valentin A. Chebanov

Beilstein J. Org. Chem. 2012, 8, 2100–2105, doi:10.3762/bjoc.8.236

• control of the MCR direction and the elaboration of synthetic methods allowing tuning of their selectivity are the current objectives that have attracted our attention and efforts over the past few years [5][6][7][8]. In some of our recent publications it was demonstrated that the direction of MCRs

• ] and derivatives of carboxylic acids [25][26]. The only MCR involving this type of aminoazole was described in our previous publication [27]. In the case of 4-amino-5-carboxamido-1,2,3-triazole, heterocyclizations can proceed in two main ways: “classical” for α-aminoazole direction with participation

• and two equivalents of cycloalkanones 2a,b (n = 1–2) in boiling dry ethanol for 3 h (Method A) proceeded as ABB’-type [28] MCR with chemodifferentiation of cyclic ketone and yielded spiroheterocycles 4a,b (31–37%, Scheme 1, Table 1) as the sole reaction products. However, better yields and purity of

The multicomponent approach to N-methyl peptides: total synthesis of antibacterial (–)-viridic acid and analogues

• Ricardo A. W. Neves Filho,
• Sebastian Stark,
• Bernhard Westermann and
• Ludger A. Wessjohann

Beilstein J. Org. Chem. 2012, 8, 2085–2090, doi:10.3762/bjoc.8.234

• a bidirectional sequence from the least- to the most-reactive amine (NMe-Val < H-Ant-OBn < H-Gly) to yield the protected tetrapeptide 2 (Scheme 1a). Alternatively, a multicomponent (MCR) approach based on a Ugi four-component reaction (Ugi-4CR) of dipeptide 3, isobutyraldehyde, methylamine and

• isonitrile 4 as the key transformation was envisioned to yield racemic viridic acid (±)-1 (Scheme 1b) [12]. Besides furnishing the desired natural product in only four steps, the MCR approach allows a ready access to analogues endowed with a proteolysis-resistant peptoid moiety [13]. Recently, we

• demonstrated that chemically more stable peptoid analogues of tubulysins, named tubugis, present cytotoxicity against cancer cell lines comparable to the native natural product [14]. Thus, it was hoped that some viridic acid analogues readily accessible by MCR may also display enhanced biological activity or

Polysiloxane ionic liquids as good solvents for β-cyclodextrin-polydimethylsiloxane polyrotaxane structures

• Narcisa Marangoci,
• Rodinel Ardeleanu,
• Laura Ursu,
• Constanta Ibanescu,
• Maricel Danu,
• Mariana Pinteala and
• Bogdan C. Simionescu

Beilstein J. Org. Chem. 2012, 8, 1610–1618, doi:10.3762/bjoc.8.184

• sample contrast. Rheological measurements The rheological measurements were performed on a Physica MCR 501 rheometer (Anton Paar, Austria) with a Peltier device for temperature control, equipped with an electronically commutated synchronous motor, allowing rheological measurements in controlled-stress

Regioselectivity in the multicomponent reaction of 5-aminopyrazoles, cyclic 1,3-diketones and dimethylformamide dimethylacetal under controlled microwave heating

• Kamal Usef Sadek,
• Ramadan Ahmed Mekheimer,
• Tahany Mahmoud Mohamed,
• Moustafa Sherief Moustafa and
• Mohamed Hilmy Elnagdi

Beilstein J. Org. Chem. 2012, 8, 18–24, doi:10.3762/bjoc.8.3

• a wide range of biological activities [3][4]. Multicomponent reactions (MCR) occupy an interesting position in organic synthesis because of their atom economy, simple procedures and convergent character [5][6][7]. An unresolved issue in multicomponent reactions is whether their selectivity is chemo

Amines as key building blocks in Pd-assisted multicomponent processes

• Didier Bouyssi,
• Nuno Monteiro and
• Geneviève Balme

Beilstein J. Org. Chem. 2011, 7, 1387–1406, doi:10.3762/bjoc.7.163

• lead to spiroacetal 22. One major drawback of this MCR is the formation of an equimolar amount of two diastereomers, which can be circumvented by further treatment of the crude mixture with 5 equivalents of MgClO4 and 1.6 equivalents of HClO4 in CH2Cl2/MeCN at room temperature. Under these acidic

A straightforward approach towards combined α-amino and α-hydroxy acids based on Passerini reactions

• Ameer F. Zahoor,
• Sarah Thies and
• Uli Kazmaier

Beilstein J. Org. Chem. 2011, 7, 1299–1303, doi:10.3762/bjoc.7.151

• : amino acids; chelated enolates; epoxides; Passerini reactions; Ugi reactions; Introduction Multicomponent reactions (MCR) are a very popular and powerful tool in modern organic synthesis [1][2][3][4]. Besides a wide range of heterocycle syntheses [5] and catalytic cross coupling reactions [6], the

Multicomponent synthesis of artificial nucleases and their RNase and DNase activity

• Anton V. Gulevich,
• Lyudmila S. Koroleva,
• Olga V. Morozova,
• Valentina N. Bakhvalova,
• Vladimir N. Silnikov and
• Valentine G. Nenajdenko

Beilstein J. Org. Chem. 2011, 7, 1135–1140, doi:10.3762/bjoc.7.131

• especially important because multicomponent reactions (MCR) could be adapted to a high throughput synthesis of libraries of compounds. It is known that isocyanide-based MCR are very efficient for synthesis of peptides and peptide molecules [19][20][21][22][23][24]. We proposed that the desired compounds 5

Multicomponent reaction access to complex quinolines via oxidation of the Povarov adducts

• Esther Vicente-García,
• Rosario Ramón,
• Sara Preciado and
• Rodolfo Lavilla

Beilstein J. Org. Chem. 2011, 7, 980–987, doi:10.3762/bjoc.7.110

• through the Povarov MCR (the interaction of anilines, aldehydes and activated olefin inputs under acid catalysis) [4][5][6][7][8]. Interestingly, this process allows cyclic enol ethers and enamines to be used as electron-rich alkenes, leading to heterocycle-fused tetrahydroquinolines, usually as a mixture

• reaction for library preparation, as one reaction affords several products, when ideally it should give only one. However, these adducts can be subjected to oxidation, which will lead to the corresponding quinolines, preserving the substituents and functionalization already introduced in the preceding MCR

• the Povarov MCR without oxidative interference [18]. The same trend (oxidation–fragmentation) can be observed using nitrobenzene [21] as the oxidant. Analogously, elemental sulfur and palladium, although requiring drastic conditions, also lead to the fragmented quinolines when the substrates bear O

Multicomponent reactions

• Thomas J. J. Müller

Beilstein J. Org. Chem. 2011, 7, 960–961, doi:10.3762/bjoc.7.107

• highly diverse. Additionally, the criterion of selectivity has to be matched with increasing significance economical and ecological aspects. In particular multicomponent reactions (MCR) [3] are masterpieces of synthetic efficiency and reaction design. These one-pot processes consist of concatenations of

• Passerini reaction and the conclusions he drew from this. Now the major conceptual challenge comprises the engineering of novel types of MCR. Most advantageously and practically, MCR can often be extended into combinatorial, solid phase or flow syntheses promising manifold opportunities for developing novel

• lead structures of active agents, catalysts and even novel molecule-based materials. This Thematic Series on multicomponent reactions represents a snapshot of a highly dynamic field and spans a broad range, from recent advances in isonitrile-based MCR to transition metal catalysis in MCR; from peptidic