Recent advances on the transition-metal-catalyzed synthesis of imidazopyridines: an updated coverage

• Gagandeep Kour Reen,
• Ashok Kumar and
• Pratibha Sharma

Beilstein J. Org. Chem. 2019, 15, 1612–1704, doi:10.3762/bjoc.15.165

Selective detection of DABCO using a supramolecular interconversion as fluorescence reporter

• Indrajit Paul,
• Debabrata Samanta,
• Sudhakar Gaikwad and
• Michael Schmittel

Beilstein J. Org. Chem. 2019, 15, 1371–1378, doi:10.3762/bjoc.15.137

• -component rectangle [Cu4(1)2(2)2]4+ and the four-component sandwich complex [Cu2(1)(2)(4)]2+ is triggered by inclusion and release of DABCO (4). The fully reversible and clean switching between two multicomponent supramolecular architectures can be monitored by fluorescence changes at the zinc porphyrin

• was demonstrated to be reversible after removing the guest. This compilation of remarkable results already indicates that guest-induced supramolecular transformations are not yet explored to their full potential. Herein, we will present the formation of self-assembled three to four-component

Doebner-type pyrazolopyridine carboxylic acids in an Ugi four-component reaction

• Maryna V. Murlykina,
• Oleksandr V. Kolomiets,
• Maryna M. Kornet,
• Yana I. Sakhno,
• Sergey M. Desenko,
• Victoriya V. Dyakonenko,
• Svetlana V. Shishkina,
• Oleksandr A. Brazhko,
• Vladimir I. Musatov,
• Alexander V. Tsygankov,
• Erik V. Van der Eycken and
• Valentyn A. Chebanov

Beilstein J. Org. Chem. 2019, 15, 1281–1288, doi:10.3762/bjoc.15.126

• -type condensation of aminopyrazoles, aldehydes and pyruvic acid [45][46] with the isocyanide-based four-component Ugi reaction. As we have shown before [47][48] the application of the CBD strategy to multicomponent Doebner-type condensations involving aminoazoles allowed the synthesis of several

• the Ugi four-component reaction to create 3 additional points of diversity. However, due to the low solubility of the pyrazolopyridine acids 4a,b under the literature standard reaction conditions for the Ugi transformation (stirring in methanol at rt and similar procedures) the reaction did not take

Steroid diversification by multicomponent reactions

• Leslie Reguera,
• Cecilia I. Attorresi,
• Javier A. Ramírez and
• Daniel G. Rivera

Beilstein J. Org. Chem. 2019, 15, 1236–1256, doi:10.3762/bjoc.15.121

• intermediate was far away from the chiral steroidal nucleus. A better stereoselectivity was reported by Bruttomesso et al. in their work on the Ugi four-component reaction (Ugi-4CR) with a steroidal aldehyde, in which the carbonyl group was directly linked at the steroidal framework [16]. As shown in Scheme 2

Ugi reaction-derived prolyl peptide catalysts grafted on the renewable polymer polyfurfuryl alcohol for applications in heterogeneous enamine catalysis

• Alexander F. de la Torre,
• Gabriel S. Scatena,
• Oscar Valdés,
• Daniel G. Rivera and
• Márcio W. Paixão

Beilstein J. Org. Chem. 2019, 15, 1210–1216, doi:10.3762/bjoc.15.118

• synthesis of prolyl pseudo-peptides having a furan ring handle, which could be subsequently incorporated into PFA during the polymerization process. Results and Discussion To this end, a solution-phase multicomponent procedure based on the Ugi four-component reaction (Ugi-4CR) [14], was employed to

• system producing γ-nitroaldehyde 5 with PFA-supported catalyst 3 packed in a microreactor. Schematic synthesis of polyfurfulyl alcohol (PFA) incorporating a prolyl peptide catalyst. AA: Amino acid. Utilization of the Ugi four-component reaction (Ugi-4CR) for the synthesis of prolyl pseudo-peptide

Multicomponent reactions (MCRs): a useful access to the synthesis of benzo-fused γ-lactams

• Edorta Martínez de Marigorta,
• Jesús M. de Los Santos,
• Ana M. Ochoa de Retana,
• Javier Vicario and
• Francisco Palacios

Beilstein J. Org. Chem. 2019, 15, 1065–1085, doi:10.3762/bjoc.15.104

• CO (23). Proposed mechanism for the palladium-catalysed synthesis of isoindoloquinazolinones 57. Four-component reaction of 2-vinylbenzoic acids 67, aryldioazonium tetrafluoroborates 68, DABCO·(SO2)2 (69) and nitriles 70. Plausible mechanism for the formation of isoindolinones 71. Three-component

• furnishes an acylpalladium complex 65, which, after elimination of hydrogen bromide and subsequent reductive elimination of palladium from intermediate 66, affords 57 with regeneration of Pd(0). 2-Vinylbenzoic acids 67 are also appropriate substrates for the preparation of isoindolinones 71 through a four

• -component reaction with aryldiazonium tetrafluoroborates 68, DABCO·(SO2)2 (69) and nitriles 70 under Ru(IV) photocatalysis with visible light and in the presence of a Lewis acid (Scheme 21) [101]. Up to 24 isoindolinone derivatives were obtained, bearing a wide variety of aryl moieties at the sulfonyl group

Synthesis of (macro)heterocycles by consecutive/repetitive isocyanide-based multicomponent reactions

• Angélica de Fátima S. Barreto and
• Carlos Kleber Z. Andrade

Beilstein J. Org. Chem. 2019, 15, 906–930, doi:10.3762/bjoc.15.88

• (Scheme 5) [23]. The synthetic strategy was based on a four-component Ugi reaction (U-4CR) followed by a three-component Ugi reaction (U-3CR). The first step involved the reaction of ammonium chloride or tritylamine, with oxo components, isocyanide, and sodium azide or TMS azide followed by acid treatment

• the first example in which the Ugi reactions were used in the construction and cyclization of peptoids in a combined fashion. The methodology was based on two consecutive four-component Ugi reactions for the construction of the acyclic precursors 84 and 89, followed by a final intramolecular Ugi

• of nonsymmetric cryptands by two sequential double Ugi-4CR-based macrocyclizations (Scheme 28). The approach also relies on MiBs strategy [45]. The main focus was on the use of the Ugi four-component reaction (Ugi-4CR) due to the tremendous capability of this process to generate molecular complexity

Synthesis of a novel category of pseudo-peptides using an Ugi three-component reaction of levulinic acid as bifunctional substrate, amines, and amino acid-based isocyanides

• Maryam Khalesi,
• Azim Ziyaei Halimehjani and
• Jürgen Martens

Beilstein J. Org. Chem. 2019, 15, 852–857, doi:10.3762/bjoc.15.82

• prominent and studied MCRs is the Ugi reaction. The Ugi four-component condensation reaction (U-4CC) between an aldehyde, an amine, a carboxylic acid and an isocyanide provides a rapid preparation of α-aminoacyl amide or pseudo-peptide derivatives. These biologically active peptide-like molecules can be

• for Ugi reactions because it has two functional groups in its structure. By the way, using bifunctional chemicals in Ugi four-component condensation reaction (4CC) converts it to an Ugi three-component condensation reaction (3CC) and this is identified as an Ugi-4-centre-3-component reaction (U-4C-3CR

Synthesis of indole–cycloalkyl[b]pyridine hybrids via a four-component six-step tandem process

• Muthumani Muthu,
• Rakkappan Vishnu Priya,
• Abdulrahman I. Almansour,
• Raju Suresh Kumar and
• Raju Ranjith Kumar

Beilstein J. Org. Chem. 2018, 14, 2907–2915, doi:10.3762/bjoc.14.269

• Department of Chemistry, College of Science, King Saud University, Riyadh 11451, Saudi Arabia 10.3762/bjoc.14.269 Abstract The one-pot four-component reaction of 3-(1H-indol-3-yl)-3-oxopropanenitriles, aromatic aldehydes, cycloalkanones and ammonium acetate occurred via a six-step tandem Knoevenagel

• four-component reaction of cyclic/acyclic ketones, malononitrile, aromatic aldehyde and ammonium acetate affording 2-amino-3-cyanopyridine derivatives have been explored extensively [45][46][47][48][49][50][51][52][53][54][55]. However, syntheses of pyridine scaffolds bearing an indole side chain have

• ]. Recently we reported the synthesis of pyridine/benzo-fused cyclododecanes through a four-component tandem reaction [70]. In continuation we herein report the synthesis of novel indole substituted cycloalkyl[b]pyridine-3-carbonitriles from a one-pot six-step tandem protocol involving 3-(1H-indol-3-yl)-3

An overview on recent advances in the synthesis of sulfonated organic materials, sulfonated silica materials, and sulfonated carbon materials and their catalytic applications in chemical processes

• Hashem Sharghi,
• Pezhman Shiri and
• Mahdi Aberi

Beilstein J. Org. Chem. 2018, 14, 2745–2770, doi:10.3762/bjoc.14.253

• synthesis of tetrahydrobenzo[a]xanthenone derivatives 48a and the four component synthesis of tetrahydrobenzo[a]acridinone derivatives 48b were performed with good to excellent yields under solvent-free conditions at 75–85 °C within short reaction times using the higher acidic/stable ILs containing

Gold-catalyzed post-Ugi alkyne hydroarylation for the synthesis of 2-quinolones

• Xiaochen Du,
• Jianjun Huang,
• Anton A. Nechaev,
• Ruwei Yao,
• Jing Gong,
• Erik V. Van der Eycken,
• Olga P. Pereshivko and
• Vsevolod A. Peshkov

Beilstein J. Org. Chem. 2018, 14, 2572–2579, doi:10.3762/bjoc.14.234

• address this issue by employing propargylamides 7 obtained by a four-component Ugi reaction of propiolic acids 3, aldehydes 4, isocyanides 5 and 3,5-dimethoxyaniline (6a) (Scheme 2). We anticipated that the resulting adducts 7 would readily produce 2-quinolones 8 bearing a branched substituent on the

• -oriented approach towards 2-quinolones bearing a branched substituent on the nitrogen atom. The strategy relies on the application of a four-component Ugi reaction followed by a gold-catalyzed intramolecular alkyne hydroarylation. The developed process has a broad scope and simple reaction settings

Cobalt- and rhodium-catalyzed carboxylation using carbon dioxide as the C1 source

• Tetsuaki Fujihara and
• Yasushi Tsuji

Beilstein J. Org. Chem. 2018, 14, 2435–2460, doi:10.3762/bjoc.14.221

• reductant, carboxyzincation and the four-component coupling reaction between alkyne, acrylates, CO2, and zinc occur efficiently. Rh complexes also catalyze the carboxylation of arylboronic esters, C(sp2)–H carboxylation of aromatic compounds, and hydrocarboxylation of styrene derivatives. The Rh-catalyzed

• carboxylation of allylarenes when a suitable ligand is used. In the presence of zinc powder, the Co-catalyzed carboxyzincation of alkynes and the four-component coupling reaction between alkyne, acrylates, CO2, and zinc proceed in an efficient manner. Visible-light-driven hydrocarboxylation reactions are shown

• , thereby giving the carboxyzincated product and regenerating Co(I) species A (step c). We also achieved the four-component coupling of alkynes 16, acrylates 18, CO2, and Zn metal, as depicted in Scheme 18 [40]. As a model reaction, the reaction using diphenylacetylene (16h), butyl acrylate (18a), CO2, and

Methyl isocyanide as a convertible functional group for the synthesis of spirocyclic oxindole γ-lactams via post-Ugi-4CR/transamidation/cyclization in a one-pot, three-step sequence

• Amarendar Reddy Maddirala and
• Peter R. Andreana

Beilstein J. Org. Chem. 2018, 14, 875–883, doi:10.3762/bjoc.14.74

• economical, simple and generate ample molecular diversity with the ease of using readily available starting materials. Developing new, post-modified Ugi-four-component reaction (Ugi-4CR) transformations in domino cyclization [12][13][14][15] sequences are very important for achieving unprecedented chemical

• spirocyclic oxindole γ-lactams). There have been other groups in the past, including our own research group, who have reported on post-modified Ugi-four-component synthetic strategies (Scheme 1) towards the synthesis of 2-oxindoles and spiro[indoline-3,2'-pyrrole]-2,5'(1'H)-diones and spiro[indoline-3,2

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

• -isomer in slightly higher amounts than the trans-isomer. A four-component reaction having ethyl acetoacetate (81) as fourth component resulted in the formation of the same pyrazolo[3,4-b]pyridine derivative 95 showing no involvement of any additional fourth component (Scheme 27). Dandia et al. [76] also

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

• bearing 1,5-disubstituted tetrazoles. Our strategy was accomplished in only three steps: first, a one-pot hydrazino-Ugi-azide four-component reaction; second a hydrazinolysis and finally an additional hydrazino-Ugi-azide reaction. This sequence provides the title compounds in moderate to excellent yields

One-pot syntheses of blue-luminescent 4-aryl-1H-benzo[f]isoindole-1,3(2H)-diones by T3P^® activation of 3-arylpropiolic acids

• Melanie Denißen,
• Alexander Kraus,
• Guido J. Reiss and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2017, 13, 2340–2351, doi:10.3762/bjoc.13.231

• varying the reaction conditions the potential of the sequence can be extended. An increase of the T3P® concentration to 2.0 equiv leads to the regioselective formation of (E)-2,9-diphenyl-3-(phenylimino)-2,3-dihydro-1H-benzo[f]isoindol-1-one (5) in 15% yield in the sense of a pseudo four-component

• )-diones 4. Modified sequence for the synthesis of acceptor-substituted 4-aryl-1H-benzo[f]isoindole-1,3(2H)-diones 4. Pseudo four-component synthesis of (E)-2,9-diphenyl-3-(phenylimino)-2,3-dihydro-1H-benzo[f]isoindol-1-one (5). Synthesis of 6-phenyl-12H-benzo[f]benzo[4,5]imidazo[2,1-a]isoindol-12-one (6

Preactivation-based chemoselective glycosylations: A powerful strategy for oligosaccharide assembly

• Weizhun Yang,
• Bo Yang,
• Sherif Ramadan and
• Xuefei Huang

Beilstein J. Org. Chem. 2017, 13, 2094–2114, doi:10.3762/bjoc.13.207

• oligosaccharides including those containing both 1,2-cis and 1,2-trans linkages, branching sequences and sulfate esters. For example, a four component preactivation-based one-pot synthesis was designed to synthesize Globo-H, an important tumor-associated carbohydrate antigen (Scheme 18) [60]. Globo-H

New tricks of well-known aminoazoles in isocyanide-based multicomponent reactions and antibacterial activity of the compounds synthesized

• Maryna V. Murlykina,
• Maryna N. Kornet,
• Sergey M. Desenko,
• Svetlana V. Shishkina,
• Oleg V. Shishkin,
• Aleksander A. Brazhko,
• Vladimir I. Musatov,
• Erik V. Van der Eycken and
• Valentin A. Chebanov

Beilstein J. Org. Chem. 2017, 13, 1050–1063, doi:10.3762/bjoc.13.104

• amine component in Ugi and Groebke–Blackburn–Bienaymé multicomponent reactions. The first example of an application of aminoazoles in an Ugi four-component reaction was discovered and novel features of a Groebke–Blackburn–Bienaymé cyclocondensation are established and discussed. The heterocycles

• -based MCRs as the Ugi four-component reaction (Ugi-4CR) and the Groebke–Blackburn–Bienaymé reaction (GBB-3CR) in combination with post-cyclizations are powerful tools to access diversity as well as complexity in a one-pot procedure; in this way they largely cover the available chemical space [9][10][11

• -diaryl-1H-imidazo[1,2-b]pyrazole-7-carboxamides (Groebke–Blackburn–Bienaymé reaction). In contrast, 3-amino-5-methylisoxazole acted as a primary amine in Ugi four-component reaction with aromatic aldehydes, phenylpropiolic acid and tert-butylisocyanide giving N-(1-arylethyl-2-(tert-butylamino)-2-oxo)-N

Synthesis of structurally diverse 3,4-dihydropyrimidin-2(1H)-ones via sequential Biginelli and Passerini reactions

• Andreas C. Boukis,
• Baptiste Monney and
• Michael A. R. Meier

Beilstein J. Org. Chem. 2017, 13, 54–62, doi:10.3762/bjoc.13.7

• dihydropyridine synthesis (1882), the Biginelli dihydropyrimidone synthesis (1891), the Mannich reaction (1912), the Passerini three-component reaction (1921) and the Ugi four-component reaction (1959) [9]. In this work, we used Biginelli and Passerini reactions to synthesize highly functionalized compounds

Synthesis of acylhydrazino-peptomers, a new class of peptidomimetics, by consecutive Ugi and hydrazino-Ugi reactions

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

Beilstein J. Org. Chem. 2016, 12, 2865–2872, doi:10.3762/bjoc.12.285

• for the synthesis of acylhydrazino-peptomers, a new class of peptidomimetics. The key idea in this approach is based on a simple route using a one-pot hydrazino-Ugi four-component reaction followed by a hydrazinolysis or hydrolysis reaction and subsequent hydrazino-Ugi reaction or classical Ugi

• difficult sequences [48]. It is therefore important to have alternative methods for the fast and easy construction of such important compounds. In this sense, the Ugi four-component reaction (U-4CR) has proven to be a robust and versatile method for the synthesis of peptoids and peptide-peptoid hybrids

• multicomponent reactions (Scheme 1): the hydrazino-Ugi four-component reaction (HU-4CR) and the classical Ugi reaction (U-4CR). The strategy was based on the formation of an acylhydrazino-peptomer via an initial hydrazino-Ugi reaction followed by a hydrazinolysis reaction (or ester hydrolysis) and a subsequent

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

• found in natural and pharmaceutical products. Results and Discussion Multicomponent motifs to build single rings In this section we consider the partitioning of 3- to 12-membered monocyclic rings according to two-, three-, and four-component couplings since these ring sizes and partitions have immediate

• circle, its algebraic representation is indistinguishable from its ring dissection map representation. where r is the ring size (4, 6, 8, …). where r is the ring size (3, 5, 7, …). (iii) four-component couplings Equation 4 and Equation 5 give the relationships for the number of unique four-partitions of

• heterocyclic ring that contains only one nitrogen atom instead of two. Scheme 12 shows a novel [2 + 2 + 1 + 1] four-component strategy by Orru [193][194]. Since the Biginelli adduct is an even-membered ring with alternating nucleophilic and electrophilic centres, all but two of the cited examples do not

Application of heterocyclic aldehydes as components in Ugi–Smiles couplings

• Katelynn M. Mason,
• Michael S. Meyers,
• Abbie M. Fox and
• Sarah B. Luesse

Beilstein J. Org. Chem. 2016, 12, 2032–2037, doi:10.3762/bjoc.12.191

• and have inspired the development of new multicomponent coupling reactions. Isocyanide-based multicomponent couplings [1], led by the foundational Ugi four-component coupling [2][3], have been used extensively for the synthesis of natural products and the preparation of diverse heterocyclic scaffolds

• reactants for the four-component Ugi–Smiles coupling [21]. A notable exception is one reported example of 2-furaldehyde participating in a Ti(O-iPr)4-catalyzed modified Ugi–Smiles reaction that used an isocyanide as an amine equivalent [22]. We recently reported a successful tandem Ugi–Smiles intramolecular

• , initial studies evaluated only amines that included an available alkene for participation in a tandem US-IMDA reaction. However, these amine components provided access to uncyclized Ugi–Smiles adducts, demonstrating the first successful four-component Ugi–Smiles reactions with a furyl-substituted aldehyde

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

• phosphite. When butanediones 128 with a larger substituent than Me were used, only monophosphonates 129 were obtained. The second method comprises a one-pot four-component reaction of diamines 130, ketones 131 and phosphites 132 in the presence of FeCl3 as a catalyst to give benzodiazepinylphosphonates 133

• four-component reaction through a methyleneaziridine ring-opening process has been developed for the synthesis of α-aminophosphonates [76]. Thus, the one-pot reaction between methyleneaziridines 173, Grignard reagents 174, alkyl halides 175 and dialkyl phosphonates in the presence of CuI afforded

• )phosphonates. Synthesis of phosphonodihydropyrans via a domino Knoevenagel/hetero-Diels–Alder process. Multicomponent synthesis of phosphonodihydrothiopyrans via a domino Knoevenagel/hetero-Diels–Alder process. One-pot four-component synthesis of 1,2-dihydroisoquinolin-1-ylphosphonates under multicatalytic

Modular synthesis of the pyrimidine core of the manzacidins by divergent Tsuji–Trost coupling

• Sebastian Bretzke,
• Stephan Scheeff,
• Felicitas Vollmeyer,
• Friederike Eberhagen,
• Frank Rominger and
• Dirk Menche

Beilstein J. Org. Chem. 2016, 12, 1111–1121, doi:10.3762/bjoc.12.107

• such procedures were evaluated within the preliminary study. The first protocol that we analyzed was reported by the group of Tian. It involves a four-component coupling of aldehyde 10 with CbzCl for activation of the nitrogen source, HMDS and allyltrimethylsilane (11) in the presence of catalytic

Muraymycin nucleoside-peptide antibiotics: uridine-derived natural products as lead structures for the development of novel antibacterial agents

• Daniel Wiegmann,
• Stefan Koppermann,
• Marius Wirth,
• Giuliana Niro,
• Kristin Leyerer and
• Christian Ducho

Beilstein J. Org. Chem. 2016, 12, 769–795, doi:10.3762/bjoc.12.77

• urea dipeptide 27 [96][97]. Starting from the uridine derivative 28 used in the synthesis of (+)-caprazol, Ichikawa and Matsuda built up muraymycin D2 and its epimer (Scheme 4). They used an Ugi four-component reaction with an isonitrile derivative 29 obtained from the uridine-derived core structure 28