Hypervalent organoiodine compounds: from reagents to valuable building blocks in synthesis

• Gwendal Grelier,
• Benjamin Darses and
• Philippe Dauban

Beilstein J. Org. Chem. 2018, 14, 1508–1528, doi:10.3762/bjoc.14.128

• ligands, and tolerates a variety of substituents on both the indole and the iodonium salt. However, the atom-economy of the reaction is limited by the need to use the iodonium salts in slight excess (1.5 equivalents). Another multicomponent reaction has been designed for the preparation of

5-Aminopyrazole as precursor in design and synthesis of fused pyrazoloazines

• Ranjana Aggarwal and
• Suresh Kumar

Beilstein J. Org. Chem. 2018, 14, 203–242, doi:10.3762/bjoc.14.15

• described the construction of spiro[indoline-3,4'-pyrazolo[3,4-b]pyridine] derivatives 57 from the multicomponent reaction of 5-amino-3-hydroxy-1-phenyl-1H-pyrazole (46), ketones 56 and isatin 54 in water/acetic acid (3:1) at 90 °C (Scheme 12). Quiroga et al. [58] reported the synthesis of the pyrazolo[3,4

• first direct conversion of acenaphthenequinone to a naphthoic acid fragment via C–C bond cleavage in a single step. Recently, D. Anand et al. [63] have reported the synthesis of pyrazolo[3,4-b]pyridine derivatives 71 and 72 through the multicomponent reaction of 1-aryl-3-indolyl-5-aminopyrazoles 16

• -aminopyrazole 16, arylaldehyde 47, and 2H-thiopyran-3,5(4H,6H)-dione (79) in glacial acetic acid in presence of ammonium acetate (Scheme 20). The multicomponent reaction of 5-amino-3-hydroxypyrazoles 82, substituted salicylic aldehydes 83 and acetylacetic ester 81 in acetic acid with few drops of piperidine was

Consecutive hydrazino-Ugi-azide reactions: synthesis of acylhydrazines bearing 1,5-disubstituted tetrazoles

• Angélica de Fátima S. Barreto,
• Veronica Alves dos Santos and
• Carlos Kleber Z. Andrade

Beilstein J. Org. Chem. 2017, 13, 2596–2602, doi:10.3762/bjoc.13.256

• tetrazoles are intermolecular cycloaddition reactions and isocyanide-based multicomponent reactions (IMCRs). Indeed, the Ugi-multicomponent reaction using TMSN3 (trimethylsilyl azide) as acid component, originally reported by Ugi in 1961 [10], is one of the best and most general methods for the synthesis of

• and 6 with hydrazine monohydrate, following a known procedure (Scheme 2) [31]. To access the acylhydrazino-tetrazoles, the hydrazides 2a–c were subjected to a multicomponent reaction comprising an aldehyde or ketone 7a–h, trimethylsilyl azide (TMSN3, 8), methyl isocyanoacetate (9) and ZnCl2 (10 mol

One-pot three-component route for the synthesis of S-trifluoromethyl dithiocarbamates using Togni’s reagent

• Azim Ziyaei Halimehjani,
• Martin Dračínský and
• Petr Beier

Beilstein J. Org. Chem. 2017, 13, 2502–2508, doi:10.3762/bjoc.13.247

• reported a novel multicomponent reaction for the synthesis of S-trifluoromethyl dithiocarbamates from secondary amines, CS2 and Togni's reagent in moderate to good yields. Under similar conditions, a primary amine afforded the corresponding isothiocyanate in excellent yield. The presence of dithiocarbamate

Mechanochemical synthesis of small organic molecules

• Tapas Kumar Achar,
• Anima Bose and
• Prasenjit Mal

Beilstein J. Org. Chem. 2017, 13, 1907–1931, doi:10.3762/bjoc.13.186

• [120]. Mechanochemical Hantzsch pyrrole synthesis [121]. Mechanochemical Biginelli reaction by subcomponent synthesis approach [133]. Mechanochemical asymmetric multicomponent reaction[134]. Mechanochemical Paal–Knorr pyrrole synthesis [142]. Mechanochemical synthesis of benzothiazole using ZnO nano

NHC-catalyzed cleavage of vicinal diketones and triketones followed by insertion of enones and ynones

• Ken Takaki,
• Makoto Hino,
• Akira Ohno,
• Kimihiro Komeyama,
• Hiroto Yoshida and
• Hiroshi Fukuoka

Beilstein J. Org. Chem. 2017, 13, 1816–1822, doi:10.3762/bjoc.13.176

• study on the multicomponent reaction of thiazolium carbenes, benzils and water to yield 1,4-thiazin-3-ones [22]. Although the initial process producing the salt 12 was similar, the total mode of the two reactions was quite different, that is, stoichiometric vs catalytic reaction with respect to the

A practical and efficient approach to imidazo[1,2-a]pyridine-fused isoquinolines through the post-GBB transformation strategy

• Taofeng Shao,
• Zhiming Gong,
• Tianyi Su,
• Wei Hao and
• Chao Che

Beilstein J. Org. Chem. 2017, 13, 817–824, doi:10.3762/bjoc.13.82

• conditions and a broad substrate scope, allowing for the rapid construction of structurally complex and diverse heterocycles in moderate to good yields. Keywords: Groebke–Blackburn–Bienaymé reaction; imidazo[1,2-a]pyridines; isoquinolines; multicomponent reaction; Ugi reaction; Introduction Imidazo[1,2-a

• discovery [22][23][24][25][26][27]. The Ugi reaction [28], an elegant pioneer of a multicomponent reaction, represents a powerful synthetic tool to assemble versatile peptide-like compounds. It has found many applications in the facile synthesis of natural products and biologically interesting molecules [29

• good yields through the GBB multicomponent reaction/Au-catalyzed cyclization strategy. The described method provides a new tool for a rapid compound library generation from readily accessible starting materials. Further, the protocol tolerates a broad substrate scope, which will make it attractive for

Brønsted acid-mediated cyclization–dehydrosulfonylation/reduction sequences: An easy access to pyrazinoisoquinolines and pyridopyrazines

• Ramana Sreenivasa Rao and
• Chinnasamy Ramaraj Ramanathan

Beilstein J. Org. Chem. 2017, 13, 428–440, doi:10.3762/bjoc.13.46

• for the synthesis of many alkaloids (Figure 1) [16]. To synthesize pyrazinoisoquinoline and its derivatives, various approaches such as the Ugi multicomponent reaction [17] amidoalkylation [18][19], N-acyliminium ion cyclization [20] and a radical cyclization [21] have been reported. To this end

NMR reaction monitoring in flow synthesis

• M. Victoria Gomez and
• Antonio de la Hoz

Beilstein J. Org. Chem. 2017, 13, 285–300, doi:10.3762/bjoc.13.31

• , (iii) reaction conditions can be examined very easily by real-time monitoring and (iv) integration of small amounts of products and intermediates would be possible [45]. Harbou et al. [46] performed a kinetic study on the multicomponent reaction of acetaldehyde and water to produce poly

Regiochemistry of cyclocondensation reactions in the synthesis of polyazaheterocycles

• Patrick T. Campos,
• Leticia V. Rodrigues,
• Andrei L. Belladona,
• Caroline R. Bender,
• Juliana S. Bitencurt,
• Fernanda A. Rosa,
• Davi F. Back,
• Helio G. Bonacorso,
• Nilo Zanatta,
• Clarissa P. Frizzo and
• Marcos A. P. Martins

Beilstein J. Org. Chem. 2017, 13, 257–266, doi:10.3762/bjoc.13.29

• multicomponent reaction between an α-ketoacid, a diamine such as 8d, an aldehyde, and an isonitrile Nixey et al. [32] observed an amide intermediate prior to the formation of the heterocyclic quinoxalinone. An intermediate amide was also observed by Sherman et al. [33] in the reaction between an α-ketoacid

Multicomponent synthesis of spiropyrrolidine analogues derived from vinylindole/indazole by a 1,3-dipolar cycloaddition reaction

• Manjunatha Narayanarao,
• Lokesh Koodlur,
• Vijayakumar G. Revanasiddappa,
• Subramanya Gopal and
• Susmita Kamila

Beilstein J. Org. Chem. 2016, 12, 2893–2897, doi:10.3762/bjoc.12.288

• in the construction of functionalized spiro compounds. We report herein the facile synthesis of novel spiropyrrolidine compounds through a one-pot three-component reaction involving N-substituted vinylindole/indazole, ninhydrin and sarcosine/L-proline. The present multicomponent reaction (MCR) leads

• . Conclusion In conclusion, the present work explores the use of 1,3-dipolar cycloaddition reactions for the regio- and stereospecific synthesis of functionalized spiropyrrolidines through a one-pot multicomponent reaction. This new route involving a vinyl framework gives rise to a wide array of novel

A new paradigm for designing ring construction strategies for green organic synthesis: implications for the discovery of multicomponent reactions to build molecules containing a single ring

• John Andraos

Beilstein J. Org. Chem. 2016, 12, 2420–2442, doi:10.3762/bjoc.12.236

• strategies. Biginelli adduct The Biginelli reaction [163][164][165] is by far the most studied multicomponent reaction since its discovery in 1891 with nearly 2000 citations in the literature. The 3,4-dihydro-1H-pyrimidin-2-one adduct has been made essentially by one [3 + 2 + 1] strategy via condensation of

One-pot synthesis of tetracyclic fused imidazo[1,2-a]pyridines via a three-component reaction

• Bo Yang,
• Chuanye Tao,
• Taofeng Shao,
• Jianxian Gong and
• Chao Che

Beilstein J. Org. Chem. 2016, 12, 1487–1492, doi:10.3762/bjoc.12.145

• scaffolds can be constructed in great diversity by a multicomponent reaction of amidines, aldehydes and isocyanides. This MCR, a variant of the Ugi reaction [24][25], was discovered independently by three groups and is known as the Groebke–Blackburn–Bienaymé (GBB) reaction [26][27][28][29]. The reaction

• conclusion we have developed a GBB-based multicomponent reaction of isatins, 2-animopyridines and isocyanides, which provides a direct and rapid access to diverse tetracylic fused imidazo[1,2-a]pyridines with moderate yields. To the best of our knowledge, the described chemistry represents the first example

• high efficiency and simple operation will make it have potential applications in the compound library synthesis. Experimental Typical procedure for multicomponent reaction. To a solution of isatin (3, 1.0 mmol), 2-aminopyridine (2, 1.35 mmol) and isocyanide (4, 1.35 mmol) in 4 mL of n-butyl alcohol was

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

• ) [39]. 2.2.3 Isoindolinylphosphonates: A one-pot diastereoselective multicomponent reaction towards (isoindolin-1-one-3-yl)phosphonates has been developed by Ordóñez et al. (Scheme 14) [40]. The reaction of 2-formylbenzoic acid (55) with (S)- or (R)-amines 56 and dimethyl phosphonate under solvent and

• . Multicomponent reaction of alkanedials, acetamide and acetyl chloride in the presence of PCl3 and acetic acid. An oxidative domino three-component synthesis of polyfunctionalized pyridines. A sequential one-pot three-component synthesis of polysubstituted pyrroles. Three-component decarboxylative coupling of

Diastereoselective Ugi reaction of chiral 1,3-aminoalcohols derived from an organocatalytic Mannich reaction

• Samantha Caputo,
• Andrea Basso,
• Lisa Moni,
• Renata Riva,
• Valeria Rocca and
• Luca Banfi

Beilstein J. Org. Chem. 2016, 12, 139–143, doi:10.3762/bjoc.12.15

• subjected to an Ugi multicomponent reaction under classical or Lewis acid-promoted conditions with diastereoselectivities ranging from moderate to good. This approach represents a step-economical path to enantiomerically pure, polyfunctionalized peptidomimetics endowed with three stereogenic centers

• point of view of atom- and step-economy, the use of chiral amines that are retained in the final products will be more valuable [27]. In this case they are not "chiral auxiliaries" and are not removed after the multicomponent reaction, and they contribute to the diversity of the final products. However

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

• : aminoalcohols; free-radical addition; imine; multicomponent reaction; titanium salts; Introduction Multicomponent reactions (MCRs) represent a green approach towards the synthesis of polyfunctionalized molecules by promoting multiple bond-forming mechanisms in a one-pot synthesis [1][2][3][4][5][6][7

• amino derivatives, under mild conditions without requiring isolation and purification of intermediates, according to a classical multicomponent reaction. Experimental All materials were purchased from commercial suppliers and used without further purification. All reactions were performed at room

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

• ]. Electrooxidation to prepare a chiral oxidation mediator and application to the kinetic resolution of sec-alcohols [58]. Electrooxidation reactions on 4-membered ring systems [68]. An electrochemical multicomponent reaction where a carbon felt anode and platinum cathode were utilised and carried out at −78 °C [22

The unexpected influence of aryl substituents in N-aryl-3-oxobutanamides on the behavior of their multicomponent reactions with 5-amino-3-methylisoxazole and salicylaldehyde

• Volodymyr V. Tkachenko,
• Elena A. Muravyova,
• Sergey M. Desenko,
• Oleg V. Shishkin,
• Svetlana V. Shishkina,
• Dmytro O. Sysoiev,
• Thomas J. J. Müller and
• Valentin A. Chebanov

Beilstein J. Org. Chem. 2014, 10, 3019–3030, doi:10.3762/bjoc.10.320

• ; catalysis; chemoselectivity; heterocycle; multicomponent reaction; ultrasonication; salicylaldehyde; Introduction Generally, considerable interest in heterocyclic compounds is due to their key role in biological processes in nature and biological activity. In particular, condensed heterocycles bearing a

• alia, ultrasonic activation was applied to promote this multicomponent reaction. It was established that the three-component cyclocondensation of the starting compounds under ultrasonication at room temperature for 4 h led to the selective formation of the substituted chroman-3-carboxamide 4a in 58

One-pot four-component reaction for convenient synthesis of functionalized 1-benzamidospiro[indoline-3,4'-pyridines]

• Chao Wang,
• Yan-Hong Jiang and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2014, 10, 2671–2676, doi:10.3762/bjoc.10.281

• ; multicomponent reaction; one-pot reaction; spiro[indoline-3,4'-pyridine]; Introduction The spirooxindole system is the core structure of many natural products and pharmaceutically important structures with notable structural complexity and biological activities of great interest [1][2][3][4]. Accordingly, many

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

• -imidazo[1,2-b]pyrazole; isocyanide; multicomponent reaction; N-heterocycles; Introduction For the relatively rapid design and construction of a diverse, large pharmacophore library, the basic concepts of diversity-oriented synthesis and isocyanide-based multicomponent reactions, such as the Ugi four

Photochemical approach to functionalized benzobicyclo[3.2.1]octene structures via fused oxazoline derivatives from 4- and 5-(o-vinylstyryl)oxazoles

• Ivana Šagud,
• Simona Božić,
• Željko Marinić and
• Marija Šindler-Kulyk

Beilstein J. Org. Chem. 2014, 10, 2222–2229, doi:10.3762/bjoc.10.230

• multicomponent reaction is slightly modified, compared to the described method [33], in order to optimize the yields. The yield of 4-oxazole derivative 1 was 50% whereas the best result found for the 5-oxazole derivative 2 was 22%. The required oxazole-4/5-carbaldehydes (3, 4) [34][35][36] were prepared from

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

• economy, wide substrate scope and high yields. Keywords: α-amino amidines; iodine; isocyanide; multicomponent reaction; Ugi reaction; Introduction Amidines are a class of organic compounds exhibiting a variety of biological activity that makes them potential candidates for drug development and discovery

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

• assistance [17]. In view of the fact, that the two-step conversion 2→4a,b→5a,b was characterized by only moderate overall yields (59%, resp. 43%) it was considered to merge these two steps into a one-pot multicomponent reaction. The latter type of reaction attracts increasing attention in organic chemistry

• multicomponent reaction following the path 2→9→7. Azine N-oxides of type 7 are estimated to be of particular interest due to the possibility of further functionalization adjacent to the nitrogen atom (position 4), for instance by palladium-catalyzed direct arylation reactions [31]. NMR spectroscopic

• ). In the case of the former (5) the described multicomponent reaction approach is superior compared to the sequential one, whereas the step-by-step synthesis of N-oxides 7 is still characterized by higher overall yields. In addition, in-depth NMR studies with all synthesized compounds were performed

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

• . Biochemical properties of the novel nucleoside analogs are also presented (if provided by the authors). Keywords: multicomponent reaction; nucleoside analog; nucleoside antibiotics; nucleoside construction; nucleoside modification; Introduction Chemical modifications of natural ribose or 2'-deoxyribose

• 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

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