Nucleophile-induced ring contraction in pyrrolo[2,1-c][1,4]benzothiazines: access to pyrrolo[2,1-b][1,3]benzothiazoles

• Ekaterina A. Lystsova,
• Maksim V. Dmitriev,
• Andrey N. Maslivets and
• Ekaterina E. Khramtsova

Beilstein J. Org. Chem. 2023, 19, 646–657, doi:10.3762/bjoc.19.46

• -aminothiophenol with donor–acceptor cyclopropanes (Scheme 2, entry 10) [27], condensations of o-aminothiophenol with 4-oxo acids or their derivatives (Scheme 2, entry 11) [2][28][29][30][31] and cascade reactions of o-aminothiophenol, furfural and anhydrides of 2,3-unsaturated carboxylic acids (Scheme 2, entry 12

C3-Alkylation of furfural derivatives by continuous flow homogeneous catalysis

• Grédy Kiala Kinkutu,
• Catherine Louis,
• Myriam Roy,
• Juliette Blanchard and
• Julie Oble

Beilstein J. Org. Chem. 2023, 19, 582–592, doi:10.3762/bjoc.19.43

• .19.43 Abstract The C3-functionalization of furfural using homogeneous ruthenium catalysts requires the preinstallation of an ortho-directing imine group, as well as high temperatures, which did not allow scaling up, at least under batch conditions. In order to design a safer process, we set out to

• develop a continuous flow process specifically for the C3-alkylation of furfural (Murai reaction). The transposition of a batch process to a continuous flow process is often costly in terms of time and reagents. Therefore, we chose to proceed in two steps: the reaction conditions were first optimized

• formation of the imine directing group and the C3-functionalization with some vinylsilanes and norbonene. Keywords: biomass; C–H activation; flow; furfural; homogeneous catalysis; Introduction The conversion of biomass derivatives into value-added products is one of the key branches of green chemistry and

Oxa-Michael-initiated cascade reactions of levoglucosenone

• Julian Klepp,
• Thomas Bousfield,
• Hugh Cummins,
• Sarah V. A.-M. Legendre,
• Jason E. Camp and
• Ben W. Greatrex

Beilstein J. Org. Chem. 2022, 18, 1457–1462, doi:10.3762/bjoc.18.151

• chemistry; levoglucosenone; oxa-Michael reaction; Introduction (−)-Levoglucosenone (1) is formed from the acid-catalyzed pyrolysis of cellulose along with minor amounts of furfural and 5-methylfurfural [1][2][3]. It has emerged as a promising starting material for enantioselective synthesis from materials

• processes in 1, such as the Baylis–Hillman reaction [14], and the Rauhut–Currier reaction which gives dimers such as 2 as well as higher oligomers [10][15]. An oxa-Michael-initiated three-component intermolecular reaction of 1 with furfural and water has been reported to result in enone 3 (Figure 1) [16

• ]. The reaction is interesting as both furfural and 1 are present along with water in crude biomass pyrolysates, and so the reaction could affect yields of 1 [3][17][18]. Samet and co-workers have reported a similar condensation of 1 with salicylaldehyde resulting in chiral chromene derivative 4 [19][20

Modular synthesis of 2-furyl carbinols from 3-benzyldimethylsilylfurfural platforms relying on oxygen-assisted C–Si bond functionalization

• Sebastien Curpanen,
• Per Reichert,
• Gabriele Lupidi,
• Giovanni Poli,
• Julie Oble and
• Alejandro Perez-Luna

Beilstein J. Org. Chem. 2022, 18, 1256–1263, doi:10.3762/bjoc.18.131

• biomass-derived furfural and 5-methylfurfural, are converted into 3-silylated 2-furyl carbinols upon condensation with organomagnesium or organolithium reagents. The hydroxy unit of the carbinol adducts can be exploited to promote C3(sp2)–Si bond functionalization through intramolecular activation. Two

• ][3]. As part of this effort, exploitation of furfural and corresponding derivatives attracts continuous attention [4][5][6][7]. In this area, we have actively investigated catalytic C–H activation reactions [8][9][10][11][12][13][14], and as part of this work, we have recently developed an iridium

• -based protocol for the catalytic C3–H silylation of furfurylimines [15]. This method allows to install a C–Si bond poised for further functionalization on the furfural unit, and thereby leads to synthetic platforms useful to access elaborated furans. This prospect was demonstrated with platforms relying

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

• of ammonia, formaldehyde, and acetaldehyde; and iii) preparation from furfural and ammonia. In addition, Hantzsch pyridine synthesis from ethyl acetoacetate, formaldehyde, and ammonia is a commonly used laboratory synthetic method. Recently, extensive and efficient methods for the construction of

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

• , 2-alkyl-3-furfural derivatives 9 and diphenylprolinol trimethylsilyl ether 11 as catalyst, and it was possible to obtain 3,4-dihydrocoumarin derivatives with excellent yields, ee and dr (Scheme 3). Using a completely different strategy from the above discussed, in which the coumarin core was the

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

• . Other examples of the use of column reactors for the catalysis of aldol reactions include: The use of immobilised aldolase enzymes for the synthesis of carbohydrates [114] and the use of a calcinated hydrolactite-packed column for the condensation of furfural with acetone [115], however, this still

Identification of volatiles from six marine Celeribacter strains

• Anuj Kumar Chhalodia,
• Jan Rinkel,
• Dorota Konvalinkova,
• Jörn Petersen and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2021, 17, 420–430, doi:10.3762/bjoc.17.38

• (20), in addition to 3-methylbutan-4-olide (21) and 4-methylhex-5-en-4-olide (22), was detected in strain-specific patterns, with almost all of these compounds present in C. marinus; only C. halophilus did not emit lactones. Furans included furan-2-ylmethanol (23), furfural (24), and 2-acetylfuran (25

Metal-free mechanochemical oxidations in Ertalyte^® jars

• Andrea Porcheddu,
• Francesco Delogu,
• Lidia De Luca,
• Claudia Fattuoni and
• Evelina Colacino

Beilstein J. Org. Chem. 2019, 15, 1786–1794, doi:10.3762/bjoc.15.172

• furfural (10b), but in low and irreproducible yields together with significant amounts of byproducts. As expected, the reaction with conjugated alcohols (cinnamic alcohol, propargyl alcohol, etc.) was less successful due to the competing chlorination of the multiple bonds. Prompted by these findings, we

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

• a well-established industry of furfural production from corncobs and sugarcane pentoses, making polymers derived from this material among the most versatile and promising due to their renewable character and easy exploitation of such biomasses [12][13]. As depicted in Scheme 1, we envisioned the

Synthesis of unnatural α-amino esters using ethyl nitroacetate and condensation or cycloaddition reactions

• Glwadys Gagnot,
• Vincent Hervin,
• Eloi P. Coutant,
• Sarah Desmons,
• Racha Baatallah,
• Victor Monnot and
• Yves L. Janin

Beilstein J. Org. Chem. 2018, 14, 2846–2852, doi:10.3762/bjoc.14.263

• improvements were observed with these conditions. Other series of trials were made to improve the overall yields of the furan-bearing α-nitro esters 6n–r. We first tried to avoid the preparation of the acetals 5n or 5o and used the previously reported direct condensation between furfural (3n) and ethyl

• yield of 6n was achieved. Moreover, without using an inert atmosphere for the initial condensation between furfural (3n) and ethyl nitroacetate (4) the overall yield of 6n dropped to 37% even when using sodium cyanoborohydride. The optimized conditions were then applied to aldehyde 3r and afforded a

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

• triglycerides with methanol, the etherification of isopentene with methanol, the esterification of palm fatty acid distillate with methanol, the dehydration of D-xylose into furfural, the production of ethyl acetate from ethanol and acetic acid, and the transesterification of palm oil with methanol into biodiesel

• arylaldehydes including 2,4-dichloro, 2,4-dimethoxy, 3,4-dimethoxy, and 3,4,5-trimethoxy. The catalyst was used up to four cycles under the optimized conditions [70]. A new strategy was proposed for the synthesis of a novel sulfonated carbon catalyst 127 using the reaction of 5-(hydroxymethyl)furfural (123

• ) with 4-hydroxybenzenesulfonic acid (p-HBSA, 124). As a simple and brief explanation of the sulfonated carbon synthesis, 5-(hydroxymethyl)furfural (123) and p-HBSA (124) were dissolved in deionized water to produce a clear brownish red solution. In continuation, the solution was heated at 358 K and

Recent developments in the asymmetric Reformatsky-type reaction

• Hélène Pellissier

Beilstein J. Org. Chem. 2018, 14, 325–344, doi:10.3762/bjoc.14.21

• cyano substituents all afforded the corresponding chiral products 32b–h in good yields (68–85%) and good to high diastereoselectivities (82–90% de). Imines derived from 4-biphenylcarbaldehyde or furfural also reacted smoothly, giving chiral products 32i,j with excellent diastereoselectivities (≥90% de

Dialkyl dicyanofumarates and dicyanomaleates as versatile building blocks for synthetic organic chemistry and mechanistic studies

• Grzegorz Mlostoń and
• Heinz Heimgartner

Beilstein J. Org. Chem. 2017, 13, 2235–2251, doi:10.3762/bjoc.13.221

• onto the terminal cyano group in 85 results in the formation of the minor product 83. Another example of a heterocyclization, which occurs with participation of an N- and a C-nucleophile was reported for the reaction of E-1a and thiosemicarbazone 86, derived from furfural. This reaction, performed in

Mechanically induced oxidation of alcohols to aldehydes and ketones in ambient air: Revisiting TEMPO-assisted oxidations

• Andrea Porcheddu,
• Evelina Colacino,
• Giancarlo Cravotto,
• Francesco Delogu and
• Lidia De Luca

Beilstein J. Org. Chem. 2017, 13, 2049–2055, doi:10.3762/bjoc.13.202

• alcohol under mechanical activation conditions provided the salicylaldehyde in nearly quantitative yield (compound 2k in Scheme 3). The reaction was also successfully expanded to heteroaromatic alcohol 1l (Scheme 3, 2-furylmethanol), giving furfural in a very good yield (90%). The mechanically induced

Fluorescent carbon dots from mono- and polysaccharides: synthesis, properties and applications

• Stephen Hill and
• M. Carmen Galan

Beilstein J. Org. Chem. 2017, 13, 675–693, doi:10.3762/bjoc.13.67

• to fructose, leads to HMF formation following three dehydration steps. Indeed, HMF formation has been identified as a dehydration product in reactions with glucose, fructose and sucrose under acidic conditions [48]. Furthermore, the team was able to show that instead of polymeric furfural structures

• nanoparticle properties. These results provide evidence that aggregation of furfural intermediates or other heteroaromatic species could be responsible for the PL and physicochemical properties observed. Fluorescent carbon dots synthesised from polysaccharides Polysaccharides are essentially polymeric sugar

Revaluation of biomass-derived furfuryl alcohol derivatives for the synthesis of carbocyclic nucleoside phosphonate analogues

• Bemba Sidi Mohamed,
• Christian Périgaud and
• Christophe Mathé

Beilstein J. Org. Chem. 2017, 13, 251–256, doi:10.3762/bjoc.13.28

• catalytic hydrogenation of furfural; the latter is obtained from the dehydration of xylose, a 5-carbon sugar derived from vegetal biomass. Furfuryl alcohol finds widespread application in the chemical industries and for example is employed for the production of synthetic fibers, fine chemicals, etc. In fine

Diels–Alder reactions in confined spaces: the influence of catalyst structure and the nature of active sites for the retro-Diels–Alder reaction

• Ángel Cantín,
• M. Victoria Gomez and
• Antonio de la Hoz

Beilstein J. Org. Chem. 2016, 12, 2181–2188, doi:10.3762/bjoc.12.208

• selectivity and atom economy. Moreover, Diels–Alder cycloadditions in combination with heterogeneous catalysts (i.e. doped-microporous materials) represent an interesting approach for the conversion of biomass feedstock into stable chemicals such as furfural derivatives, platform molecules which can be

Superelectrophilic activation of 5-hydroxymethylfurfural and 2,5-diformylfuran: organic synthesis based on biomass-derived products

• Dmitry S. Ryabukhin,
• Dmitry N. Zakusilo,
• Mikhail O. Kompanets,
• Anton A.Tarakanov,
• Irina A. Boyarskaya,
• Tatiana O. Artamonova,
• Mikhail A. Khohodorkovskiy,
• Iosyp O. Opeida and
• Aleksander V. Vasilyev

Beilstein J. Org. Chem. 2016, 12, 2125–2135, doi:10.3762/bjoc.12.202

• -(chloromethyl)furfural (1b) and 5-(bromomethyl)furfural (1c), both of which are also promising biomass-derived products [58][59], were reacted with benzene under the action of various acids (Table 3). In all cases 5-(phenylmethyl)furfural (3a) as Friedel–Crafts reaction product was obtained. Thus, only the

Scope and mechanism of the highly stereoselective metal-mediated domino aldol reactions of enolates with aldehydes

• M. Emin Cinar,
• Bernward Engelen,
• Martin Panthöfer,
• Hans-Jörg Deiseroth,
• Jens Schlirf and
• Michael Schmittel

Beilstein J. Org. Chem. 2016, 12, 813–824, doi:10.3762/bjoc.12.80

• incorporation of the two enantiomers of 7h and they are held together by hydrogen bonds (intramolecular: 1.90 Å, intermolecular: 1.93 Å) (Figure 2). Various aldehydes were also probed in the domino aldol reaction with the indium enolate of butyrophenone (1f, Scheme 4). Reactions involving 2-furfural

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

• amines in the presence of phenylacetylene, gave the corresponding coupling products in very good to excellent yields, apart from the reactions with furfural, which obtained low yields. An intriguing catalytic system composed of zinc oxide supported Au NP, activated by LED irradiation (plasmon mediated

Recent applications of the divinylcyclopropane–cycloheptadiene rearrangement in organic synthesis

• Sebastian Krüger and
• Tanja Gaich

Beilstein J. Org. Chem. 2014, 10, 163–193, doi:10.3762/bjoc.10.14

• , reduction of the remaining double bond and subsequent Krapcho decarboxylation [132] resulted in less functionalized ketone 150. Aldol condensation with furfural followed by O-allylation and Claisen rearrangement furnished enone 151. Standard functional group interconversiones were used to access TIPS

Efficient synthesis of dihydropyrimidinones via a three-component Biginelli-type reaction of urea, alkylaldehyde and arylaldehyde

• Haijun Qu,
• Xuejian Li,
• Fan Mo and
• Xufeng Lin

Beilstein J. Org. Chem. 2013, 9, 2846–2851, doi:10.3762/bjoc.9.320

• reaction was then investigated, and the results were presented in Table 2. First, we examined the scope of the aromatic aldehydes 3. Various aromatic aldehydes 3a–3l and furfural (3m) were suitable substrates, and the expected products were obtained in moderate isolated yields (39–70%) (Table 2, entries 1

Microflow photochemistry: UVC-induced [2 + 2]-photoadditions to furanone in a microcapillary reactor

• Sylvestre Bachollet,
• Kimitada Terao,
• Shin Aida,
• Yasuhiro Nishiyama,
• Kiyomi Kakiuchi and
• Michael Oelgemöller

Beilstein J. Org. Chem. 2013, 9, 2015–2021, doi:10.3762/bjoc.9.237

• Sigma-Aldrich or Alfa-Aesar and were used without further purification. Furanone 1 was synthesized from furfural following literature procedures [49]. NMR spectra were recorded on an Oxford 300 (1H 300 MHz and 13C 75 MHz) with the Varian Software VnmrJ Revision D. The residual solvent signal as used as

Preparation and ring-opening reactions of N-diphenylphosphinyl vinyl aziridines

• Ashley N. Jarvis,
• Andrew B. McLaren,
• Helen M. I. Osborn and
• Joseph Sweeney

Beilstein J. Org. Chem. 2013, 9, 852–859, doi:10.3762/bjoc.9.98

• reported direct synthesis of a vinyl aziridine bearing a phosphorus group on nitrogen [40]. Encouraged by this promising result, we next examined the scope of the reaction by using the same anion and N-Dpp imines derived from 4-bromo- and 4-fluorobenzaldehyde, furfural and 2,2-dimethylpropionaldehyde

• similar to that of the initial reaction. In particular, the imine derived from furfural yielded only (E)-vinyl aziridine 4. In the case of the vinyl aziridination of 2,2-dimethylpropionaldehyde, an inversion in stereoselectivity was observed, with Z–5 being the dominant partner of the mixture (d.r. = 5:1