The aminoindanol core as a key scaffold in bifunctional organocatalysts

• Isaac G. Sonsona,
• Eugenia Marqués-López and
• Raquel P. Herrera

Beilstein J. Org. Chem. 2016, 12, 505–523, doi:10.3762/bjoc.12.50

• dichloromethane at 15 °C (Scheme 15) [48]. Although high yields were obtained in all cases, the best enantioselectivity was provided by the bifunctional cis-aminoindanol-based squaramide 43. Under these conditions, several 1,3-dicarbonyl compounds 36 reacted with many different nitrostyrene derivatives 3 with

• very low catalytic charge (1 mol %), affording a broad scope of the enantiomerically enriched β-nitroalkyl products 38. A possible drawback of the method would be the low diastereoselectivity generally achieved for the nonsymmetrical 1,3-dicarbonyl compounds 36. In order to understand the role of the

• the proposed transition state TS12. Addition of 3-oxindoles 39 to 2-amino-1-nitroethenes 40, catalyzed by 41. Michael addition of 1,3-dicarbonyl compounds 36 to the nitroalkenes 3 catalyzed by the squaramide 43. Asymmetric aza-Henry reaction catalyzed by the aminoindanol-derived sulfinyl urea 50

(Thio)urea-mediated synthesis of functionalized six-membered rings with multiple chiral centers

• Giorgos Koutoulogenis,
• Nikolaos Kaplaneris and
• Christoforos G. Kokotos

Beilstein J. Org. Chem. 2016, 12, 462–495, doi:10.3762/bjoc.12.48

• (Scheme 42) [62]. The resulting (R)-3-nitro-2H-chromene was isolated in rather moderate optical purity. In 2010, a domino Michael hemiacetalization reaction was reported between cyclic 1,3-dicarbonyl compounds 134 and β-unsaturated α-ketoesters 87 utilizing a novel tyrosine-derived thiourea 135 (Scheme 43

Facile synthesis of 4H-chromene derivatives via base-mediated annulation of ortho-hydroxychalcones and 2-bromoallyl sulfones

• Srinivas Thadkapally,
• Athira C. Kunjachan and
• Rajeev S. Menon

Beilstein J. Org. Chem. 2016, 12, 16–21, doi:10.3762/bjoc.12.3

• ], multicomponent reactions [8], ring-closing metathesis approaches [9][10], tandem reactions of 1,3-dicarbonyl compounds [11][12] and cyclocondenzation reactions of salicylic aldehydes with α,β-unsaturated carbonyl compounds [13][14][15]. The utility of some of these methods are limited by drawbacks such as

Fe(II)/Et₃N-Relay-catalyzed domino reaction of isoxazoles with imidazolium salts in the synthesis of methyl 4-imidazolylpyrrole-2-carboxylates, its ylide and betaine derivatives

• Ekaterina E. Galenko,
• Olesya A. Tomashenko,
• Alexander F. Khlebnikov,
• Mikhail S. Novikov and
• Taras L. Panikorovskii

Beilstein J. Org. Chem. 2015, 11, 1732–1740, doi:10.3762/bjoc.11.189

• -dicarbonyl compounds under relay catalysis [31]. Taking into account the facts discussed above, we envisioned that the synthesis of 5-alkoxycarbonylpyrrol-3-ylimidazolium salts 1 could be carried out starting from easily available 5-alkoxyisoxazoles 7 [32][33] and 1-alkyl-3-phenacyl-1H-imidazolium bromides 9

• alkyl 2H-azirine-2-carboxylates can be prepared by isomerization of 5-alkoxyisoxazoles under Fe(II)-salt catalysis [30]. Quite recently this isomerization has been used for the preparation of substituted pyrrole-2-carboxylic acid derivatives by the domino reaction of 3-aryl-5-methoxyisoxazoles with 1,3

Development of variously functionalized nitrile oxides

• Haruyasu Asahara,
• Keita Arikiyo and
• Nagatoshi Nishiwaki

Beilstein J. Org. Chem. 2015, 11, 1241–1245, doi:10.3762/bjoc.11.138

• ], nitriles [6], and 1,3-dicarbonyl compounds [7] to afford the corresponding polyfunctionalized heterocyclic compounds, which are not easily obtained by other approaches. Although this protocol is expected to be useful for synthesizing polyfunctionalized compounds, it is limited by the need of a N

Highly selective palladium–benzothiazole carbene-catalyzed allylation of active methylene compounds under neutral conditions

• Antonio Monopoli,
• Pietro Cotugno,
• Carlo G. Zambonin,
• Francesco Ciminale and
• Angelo Nacci

Beilstein J. Org. Chem. 2015, 11, 994–999, doi:10.3762/bjoc.11.111

• by extending the coupling to a series of 1,3-dicarbonyl compounds and allylic carbonates (Table 2). For these reactions, to further simplify the operating procedure of the proposed protocol, we chose to use the palladium–carbene catalyst prepared in situ as reported above (Table 1, entries 20–22

On the strong difference in reactivity of acyclic and cyclic diazodiketones with thioketones: experimental results and quantum-chemical interpretation

• Andrey S. Mereshchenko,
• Alexey V. Ivanov,
• Viktor I. Baranovskii,
• Grzegorz Mloston,
• Ludmila L. Rodina and
• Valerij A. Nikolaev

Beilstein J. Org. Chem. 2015, 11, 504–513, doi:10.3762/bjoc.11.57

• , Poland 10.3762/bjoc.11.57 Abstract The 1,3-dipolar cycloaddition of acyclic 2-diazo-1,3-dicarbonyl compounds (DDC) and thioketones preferably occurs with Z,E-conformers and leads to the formation of transient thiocarbonyl ylides in two stages. The thermodynamically favorable further transformation of C

• of a wide variety of nitrogen containing heterocyclic compounds [1][2][3][4][5]. These reactions are generally known for diazoalkanes and 2-diazocarbonyl compounds, whereas similar processes with 2-diazo-1,3-dicarbonyl compounds (DDC) are far less common [6][7][8][9][10], and reported literature data

• performed a detailed experimental study of reactions of a series of 2-diazo-1,3-dicarbonyl compounds 1 with aromatic and aliphatic thioketones 2, and it was established that they occurred in a varied manner: acyclic diazodicarbonyl compounds 1 readily reacted with thioketones 2, whereas carbocyclic

The reactions of 2-ethoxymethylidene-3-oxo esters and their analogues with 5-aminotetrazole as a way to novel azaheterocycles

• Marina V. Goryaeva,
• Yanina V. Burgart,
• Marina A. Ezhikova,
• Mikhail I. Kodess and
• Viktor I. Saloutin

Beilstein J. Org. Chem. 2015, 11, 385–391, doi:10.3762/bjoc.11.44

• ; diethyl 2-ethoxymethylidenemalonate; 2-ethoxymethylidene-3-oxo esters; ethyl 2-ethoxymethylidenecyanoacetate; Introduction 2-Ethoxymethylidene-1,3-dicarbonyl compounds are widely recognized as valuable building blocks in designing various open-chain and heterocyclic compounds, including those used in

• ], antiviral [14], antimicrobial and antioxidant activity [15] have been found among them. The known tetrazolo[1,5-a]pyrimidines were synthesized by cyclocondensation of 5-AT with 1,3-dicarbonyl compounds or their derivatives [16]. Moreover, a convenient method for obtaining this heterocyclic skeleton is the

Cross-dehydrogenative coupling for the intermolecular C–O bond formation

• Igor B. Krylov,
• Vera A. Vil’ and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2015, 11, 92–146, doi:10.3762/bjoc.11.13

• works, the oxidative coupling of alcohols, aldehydes, or formamides with 1,3-dicarbonyl compounds or phenols was accomplished in the presence of tert-butyl hydroperoxide and copper salts (Table 5). In most cases, the range of phenols applicable to the coupling is limited to 2-acylphenols. However, 2

• salts, were used for the oxidative functionalization at the α-position of carbonyl compounds. N-Hydroxyimides and N-hydroxyamides 204 are involved in the oxidative C–O coupling with 1,3-dicarbonyl compounds and their hetero analogues, such as 2-substituted malononitriles and cyanoacetic esters, 205 in

• radicals 207 from N-hydroxyimides or N-hydroxyamides 204 and the one-electron oxidation of 1,3-dicarbonyl compounds via the formation of complex 208. Apparently, the oxidative coupling of 1,3-dicarbonyl compounds 209 with oximes 210 occurs via a similar mechanism [198]. The reaction takes place in the

Three-component synthesis of C₂F₅-substituted pyrazoles from C₂F₅CH₂NH₂·HCl, NaNO₂ and electron-deficient alkynes

• Pavel K. Mykhailiuk

Beilstein J. Org. Chem. 2015, 11, 16–24, doi:10.3762/bjoc.11.3

• -dicarbonyl compounds (or their synthons) with hydrazines [39][40][41][42][43][44]. In this context, novel practical methods to C2F5-pyrazoles are needed. Last year, Ma and colleagues synthesized CF3-pyrazoles by [3 + 2] cycloaddition between in situ generated CF3CHN2 and alkynes [45]. This method, however

• including several drugs contain a C2F5 group (Figure 2) [34][35][36]. The conceptually attractive C2F5-pyrazoles [37], however, still remain somewhat in the shadow [38], probably because of the lack of the corresponding chemical approaches. Predominantly, C2F5-pyrazoles are synthesized by a reaction of 1,3

Recent advances in the electrochemical construction of heterocycles

• Robert Francke

Beilstein J. Org. Chem. 2014, 10, 2858–2873, doi:10.3762/bjoc.10.303

• generated 1,2-benzoquinones via sequential Michael addition/ring closure An electrochemical method for the synthesis of benzofuran and indol derivatives is based on the oxidation of catechol in presence of 1,3-dicarbonyl compounds or analogous C,H-acidic compounds 62 (Scheme 24) [69][70][71][72]. The

• indole derivatives. Anodic anellation of catechol derivatives 66 with different 1,3-dicarbonyl compounds. Electrosynthesis of 1,2-fused indoles from catechol and ketene N,O-acetals. Reaction of N-acyliminium pools with olefins having a nucleophilic substituent. Synthesis of thiochromans using the cation

(CF₃CO)₂O/CF₃SO₃H-mediated synthesis of 1,3-diketones from carboxylic acids and aromatic ketones

• JungKeun Kim,
• Elvira Shokova,
• Victor Tafeenko and
• Vladimir Kovalev

Beilstein J. Org. Chem. 2014, 10, 2270–2278, doi:10.3762/bjoc.10.236

• syntheses of 1,3-diketones and pyrazoles directly from acids and ketones. Moreover, 1,3-diketones and pyrazoles can be obtained from unmodified β-phenylpropionic acids. Given the importance of 1,3-dicarbonyl compounds in general, we expect that this reaction has a wide application in the realm of synthetic

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

• system (Scheme 27) [98][99]. Attempts to replace the aldehyde 73a with its 3,4,6-hydroxylated counterpart failed to give the expected product [99]. Dwivedi et al. showed that the isopropylidene-protected sugars 75 reacted efficiently with urea (or thiourea) and 1,3-dicarbonyl compounds in diethylene

• The classical Hantzsch reaction provides 1,4-dihydropyrimidines (1,4-DHPs) from 1,3-dicarbonyl compounds, aldehydes and ammonia (Scheme 32) [19]. The reaction has attracted a considerable attention because of the therapeutic usefulness of drugs featuring the 1,4-DHP scaffold, i.e., nifedipine and

Less reactive dipoles of diazodicarbonyl compounds in reaction with cycloaliphatic thioketones – First evidence for the 1,3-oxathiole–thiocarbonyl ylide interconversion

• Valerij A. Nikolaev,
• Alexey V. Ivanov,
• Ludmila L. Rodina and
• Grzegorz Mlostoń

Beilstein J. Org. Chem. 2013, 9, 2751–2761, doi:10.3762/bjoc.9.309

• agreement with the other data reported for the analogous 1,3-oxathioles bearing the spiroadamantane skeleton [5][14]. Hence, the main products of the reactions of thioketones 1a,b with deactivated dipoles of the acyclic 2-diazo-1,3-dicarbonyl compounds 2a–g were 1,3-oxathioles 3 and 7. The mechanisms of the

• prepared from the corresponding 1,3-dicarbonyl compounds and arenesulfonyl azides by diazo-transfer reactions [18]. Thioketones 1a,b were prepared from the corresponding ketones by known procedures [15][16]. General procedure for the reaction of diazodicarbonyl compounds with thioketone 1a: A mixture of

• diazoalkanes, diazoesters and diazoketones [1][2][3][4]. Due to their high dipolarophilic reactivity thioketones were given the name ‘superdipolarophiles’ [3][4]. It might be expected that these highly reactive dipolarophiles could also easily react with the deactivated 1,3-dipoles of 2-diazo-1,3-dicarbonyl

Mechanistic studies on the CAN-mediated intramolecular cyclization of δ-aryl-β-dicarbonyl compounds

• Brian M. Casey,
• Dhandapani V. Sadasivam and
• Robert A. Flowers II

Beilstein J. Org. Chem. 2013, 9, 1472–1479, doi:10.3762/bjoc.9.167

• -tetralone product 2a (Scheme 1) [15]. Using this method, a variety of 1,3-dicarbonyl compounds can be mildly converted to carboxylic acids in moderate to excellent yields. In follow up studies, we found that 2-tetralone 2a could be obtained as the major product when 1a was oxidized by CAN in MeOH [16]. In

• carbonyl groups anti to each other. For TS1a’ the dihedral angle between atoms abcd = 6.4°. *The energy values for 1a’, 1g’, 1h’ and 1j’ are shown. 1g”, 1f’ and 1j” were not included for clarity. Possible products from the ortho cyclization of 1g and 1j. Oxidative conversion of 1,3-dicarbonyl compounds to

Tandem dinucleophilic cyclization of cyclohexane-1,3-diones with pyridinium salts

• Mostafa Kiamehr,
• Firouz Matloubi Moghaddam,
• Satenik Mkrtchyan,
• Volodymyr Semeniuchenko,
• Linda Supe,
• Alexander Villinger,
• Peter Langer and
• Viktor O. Iaroshenko

Beilstein J. Org. Chem. 2013, 9, 1119–1126, doi:10.3762/bjoc.9.124

• dielectrophiles has been a major research subject in both our laboratories. For example, we have studied reactions of quinolinium [36][37], isoquinolinium [38][39][40], quinazolinium [41][42] and quinoxalinium [43] salts with 1,3-bis(silyl enol ethers), i.e., masked 1,3-dicarbonyl compounds, which provided facile

Synthesis of spiro[dihydropyridine-oxindoles] via three-component reaction of arylamine, isatin and cyclopentane-1,3-dione

• Yan Sun,
• Jing Sun and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2013, 9, 8–14, doi:10.3762/bjoc.9.2

• describing that either 2-naphthylamine [22][23][24][25], functionalized 5-aminopyrazoles [26][27][28], or 2-aminobenzothiazoles [29] reacted with isatin and cyclic 1,3-dicarbonyl compounds to give the similar spiro[dihydropyridine-oxindole] (II, III in Figure 2), in which both the amino group and the aryl

• condensation of isatins with cyclic 1,3-dicarbonyl compounds [30][31][32][33], the condensation reaction of isatin with cyclopentane-1,3-dione seemed still not to have been investigated and the 3,3-bis(2-hydroxy-5-oxo-cyclopent-1-enyl)oxindoles 3a–3d have not been prepared until now. Thus, the direct

Synthesis and evaluation of new guanidine-thiourea organocatalyst for the nitro-Michael reaction: Theoretical studies on mechanism and enantioselectivity

• Tatyana E. Shubina,
• Matthias Freund,
• Sebastian Schenker,
• Timothy Clark and
• Svetlana B. Tsogoeva

Beilstein J. Org. Chem. 2012, 8, 1485–1498, doi:10.3762/bjoc.8.168

• not considered for the further studies. A similar Michael reaction of 1,3-dicarbonyl compounds with nitroolefins has been studied in some detail before [57][59]. It is generally proposed that the reaction proceeds first by deprotonation of the acidic proton of malonate 14 followed by formation of a

Organocatalytic asymmetric addition of malonates to unsaturated 1,4-diketones

• Sergei Žari,
• Tiiu Kailas,
• Marina Kudrjashova,
• Mario Öeren,
• Ivar Järving,
• Toomas Tamm,
• Margus Lopp and
• Tõnis Kanger

Beilstein J. Org. Chem. 2012, 8, 1452–1457, doi:10.3762/bjoc.8.165

• , the increase in temperature resulted in a small drop in stereoselectivity for the model reaction with catalyst VII. The mechanism of the reaction is believed to be similar to that previously reported for 1,3-dicarbonyl compounds and acyl phosphonates [23]. Squaramide IX is a bifunctional catalyst that

Synthesis of chiral sulfoximine-based thioureas and their application in asymmetric organocatalysis

• Marcus Frings,
• Isabelle Thomé and
• Carsten Bolm

Beilstein J. Org. Chem. 2012, 8, 1443–1451, doi:10.3762/bjoc.8.164

• organic transformations with hydrogen bond accepting substrates. Recently, we reported the enantioselective ring opening of cyclic meso-anhydrides and asymmetric Michael additions of 1,3-dicarbonyl compounds to nitroalkenes with thiourea-based organocatalysts [48][49]. Based on those studies and in the

Synthesis of diverse indole libraries on polystyrene resin – Scope and limitations of an organometallic reaction on solid supports

• Kerstin Knepper,
• Sylvia Vanderheiden and
• Stefan Bräse

Beilstein J. Org. Chem. 2012, 8, 1191–1199, doi:10.3762/bjoc.8.132

• ], palladium-catalyzed indole synthesis [34][35][36][37][38][39][40], cycloaddition strategies [41], C-arylation of substituted acetonitriles or 1,3-dicarbonyl compounds [42], halocyclization [43][44] and finally, reduction of ortho-fluoro-nitroarenes [42]. The significant biological properties and the

Expanding the chemical diversity of spirooxindoles via alkylative pyridine dearomatization

• Chunhui Dai,
• Bo Liang and
• Corey R. J. Stephenson

Beilstein J. Org. Chem. 2012, 8, 986–993, doi:10.3762/bjoc.8.111

• ]oxazino derivatives from N-substituted isatins and 1,3-dicarbonyl compounds with pyridine derivatives is reported. The reactions provided good to excellent yields. Further exploration of the molecular diversity of these compounds is demonstrated through Diels–Alder reactions. Keywords: chemical diversity

• ; 1,3-dicarbonyl compounds; Diels–Alder reaction; molecular diversity; pyridine dearomatization; spirooxindole; Introduction The spirooxindole is a common structural motif found in a variety of complex alkaloids [1]. Many compounds that possess a spirooxindole moiety exhibit significant biological

• ], we previously reported a Lewis acid catalyzed, three-component synthesis of spirooxindole pyranochromenedione derivatives using isatin and two 1,3-dicarbonyl compounds (Scheme 1) [14]. Mechanistically, we believed this reaction to proceed through an intermediate isatylidene 1 [15][16][17]. As a means

Enantioselective Michael addition of 2-hydroxy-1,4-naphthoquinones to nitroalkenes catalyzed by binaphthyl-derived organocatalysts

• Saet Byeol Woo and
• Dae Young Kim

Beilstein J. Org. Chem. 2012, 8, 699–704, doi:10.3762/bjoc.8.78

• to the development of asymmetric conjugate additions of 1,3-dicarbonyl compounds to various Michael acceptors [27][28][29][30][31][32][33]. Recently, the groups of Du and Zhou reported a highly enantioselective Michael addition of 2-hydroxy-1,4-naphthoquinones to nitroalkenes catalyzed by chiral

Catalyst-free and solvent-free Michael addition of 1,3-dicarbonyl compounds to nitroalkenes by a grinding method

• Zong-Bo Xie,
• Na Wang,
• Ming-Yu Wu,
• Ting He,
• Zhang-Gao Le and
• Xiao-Qi Yu

Beilstein J. Org. Chem. 2012, 8, 534–538, doi:10.3762/bjoc.8.61

• , East China Institute of Technology, Fuzhou, China, 344000; Fax: (+86)794-8258320; Tel:(+86)794-8258320 10.3762/bjoc.8.61 Abstract An environmentally benign, fast and convenient protocol has been developed for the Michael addition of 1,3-dicarbonyl compounds to β-nitroalkenes in good to excellent

• method. Herein, we report a green protocol for the Michael addition of 1,3-dicarbonyl compounds to nitroalkenes under catalyst- and solvent-free conditions (Scheme 1). Utilizing this simple, rapid, low-cost and effective procedure, various nitro diketone derivatives were synthesized in high yields

• were used as the acceptors to react with 1,3-dicarbonyl compounds under the optimized conditions. The results are given in Table 1. It can be seen that a wide range of substrates were able to participate in the reaction. A series of substituted β-nitrostyrenes with electron-withdrawing or electron

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

• 50918, Jeddah 21533, Kingdom of Saudi Arabia Chemistry Department, Faculty of Science, Kuwait University, PO Box 5969, Safat, 13060 Kuwait 10.3762/bjoc.8.3 Abstract The multicomponent reaction of 5-aminopyrazole derivatives with cyclic 1,3-dicarbonyl compounds and dimethylformamide dimethylacetal