Synthesis of 1-indanones with a broad range of biological activity

• Marika Turek,
• Dorota Szczęsna,
• Marek Koprowski and
• Piotr Bałczewski

Beilstein J. Org. Chem. 2017, 13, 451–494, doi:10.3762/bjoc.13.48

• derivative 265 having the steroid framework from 1,2-dihydro-7-methoxy-4-vinylnaphthalene (262) and α-bromo substituted cyclopentenone 263 by the SnCl4-catalyzed Diels–Alder cycloaddition [102]. In this reaction, 1-indanone 265 was obtained in 59% yield via dehydrogenation of a mixture of cycloadducts 264a–c

The reductive decyanation reaction: an overview and recent developments

• Jean-Marc R. Mattalia

Beilstein J. Org. Chem. 2017, 13, 267–284, doi:10.3762/bjoc.13.30

• decyanation reaction depends on the structure of the α-aminonitrile, stereoelectronic effects and internal strain of the molecule [68]. Chuang et al. prepared a set of α-aminoacrylonitriles 11 by a cyano-promoted aza-Diels–Alder cycloaddition [71]. The cyano groups were then removed in high yields by

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

• Científica Aplicada (IRICA), Avda. Camilo José Cela s/n, E-13071-Ciudad Real, Spain 10.3762/bjoc.12.208 Abstract Diels–Alder cycloaddition between cyclopentadiene and p-benzoquinone has been studied in the confined space of a pure silica zeolite Beta and the impact on reaction rate due to the concentration

• . Results and Discussion As it was described previously [30], the Diels–Alder reaction (DAR) between cyclopentadiene and p-benzoquinone follows the reactions outlined in Scheme 1. As expected, the Diels–Alder cycloaddition provides the kinetically controlled endo isomer that very rapidly reacts with a

• –Alder cycloaddition between cyclopentadiene and p-benzoquinone, nor the retro-Diels–Alder reaction. This result suggests that the reaction takes place on the surface of the material and the pore structure does not have any influence on the reaction rate, neither for the DAR nor for the retro-DAR. To

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

• also a competent component for Ugi–Smiles adduct formation. Keywords: Diels–Alder cycloaddition; epoxyisoindoline; multicomponent coupling reaction; tandem reaction; Ugi–Smiles coupling; Introduction Synthetic methods to efficiently prepare libraries of biologically-relevant compounds are in demand

• allylamine. This crude reaction mixture was purified via column chromatography to provide an isolated sample of 2i for characterization. Notably, product 2i underwent almost complete Diels–Alder cycloaddition even without heating after 72 hours at 23 °C. The use of 3-furaldehyde as a component resulted in

• observed for 2- and 3-furaldehyde with a variety of amine components. In the presence of a competent dienophile, the Ugi–Smiles coupling is followed by a facile intramolecular Diels–Alder cycloaddition to generate oxatricyclic N-arylepoxyisoindolines. Initial results with thiophene-2-carboxaldehyde show

Stereo- and regioselectivity of the hetero-Diels–Alder reaction of nitroso derivatives with conjugated dienes

• Lucie Brulíková,
• Aidan Harrison,
• Marvin J. Miller and
• Jan Hlaváč

Beilstein J. Org. Chem. 2016, 12, 1949–1980, doi:10.3762/bjoc.12.184

• nature of these substituents [20][94]. This can be seen for the hetero-Diels–Alder reaction of disubstituted diene 51 with p-chloronitrosobenzene (52) to give only the proximal isomer 53 (Scheme 13). Recently, the Kouklovsky group reported a highly regioselective nitroso hetero-Diels–Alder cycloaddition

• also proceeded with high stereoselectivity because of the presence of a chiral nitroso agent. The regioselective nitroso hetero-Diels–Alder cycloaddition was also observed during the reaction of 3-dienyl-2-azetidinones 62 with nitrosobenzene (47), specifically providing 1,2-oxazine-substituted β

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

• phosphorylated heterocycles is the condensation of an activated methylene component with a carbonyl compound followed by subsequent transformations such as intramolecular cyclization, Michael-type addition and hetero-Diels–Alder cycloaddition. 3.1 Domino Knoevenagel/phospha-Michael process A convenient one-pot

The synthesis of functionalized bridged polycycles via C–H bond insertion

• Jiun-Le Shih,
• Po-An Chen and
• Jeremy A. May

Beilstein J. Org. Chem. 2016, 12, 985–999, doi:10.3762/bjoc.12.97

• reaction from a functionalized 1,3-diene like 2 (Figure 2) [13][14][15][16]. However, such a reaction would not be applicable to synthesize the bicyclo[3.2.1]octane core 3 of taxuspine C, as the mechanistic requirements in a Diels–Alder cycloaddition are not met with a 1,4-diene. Strategies that may access

Separation and identification of indene–C₇₀ bisadduct isomers

• Bolong Zhang,
• Jegadesan Subbiah,
• David J. Jones and
• Wallace W. H. Wong

Beilstein J. Org. Chem. 2016, 12, 903–911, doi:10.3762/bjoc.12.88

• derivatives. In recent studies, the solar cell devices achieved power conversion efficiency as high as 7.5% for IC60BA [5] and 7.4% for IC70BA [6]. The IC70BA material used in most reports consisted of a mixture of isomers [7][8][9]. The synthesis of IC70BA involves [2 + 4] Diels–Alder cycloaddition reaction

Indenopyrans – synthesis and photoluminescence properties

• Andreea Petronela Diac,
• Ana-Maria Ţepeş,
• Albert Soran,
• Ion Grosu,
• Anamaria Terec,
• Jean Roncali and
• Elena Bogdan

Beilstein J. Org. Chem. 2016, 12, 825–834, doi:10.3762/bjoc.12.81

• halogenated lactones having the 4a,9a-fused skeleton and an ester group at position 1. The cycloaddition reaction proceeded with moderate regio- and stereoselectivity. As reported in the literature, the inverse-electron demand Diels–Alder cycloaddition of unsymmetrical olefins and oxadiazinones [33][34][35

Synthesis of constrained analogues of tryptophan

• Elisabetta Rossi,
• Valentina Pirovano,
• Marco Negrato,
• Giorgio Abbiati and
• Monica Dell’Acqua

Beilstein J. Org. Chem. 2015, 11, 1997–2006, doi:10.3762/bjoc.11.216

• reactivity upon specific substitution patterns at the indole nucleus were observed by us in competitive Diels–Alder cycloaddition/Michael addition reactions of vinylindoles with classical dienophile and in competitive cycloaddition/hydroarylation reactions with allenes, see [20][21] for a more detailed

Preparative semiconductor photoredox catalysis: An emerging theme in organic synthesis

• David W. Manley and
• John C. Walton

Beilstein J. Org. Chem. 2015, 11, 1570–1582, doi:10.3762/bjoc.11.173

• homogeneous PRC has been showcased by its exploitation in a number of total syntheses. For example, (+)-gliocladin C was synthesized by Stephenson [9], natural product heitziamide A was made by Yoon and co-workers via a PRC Diels−Alder cycloaddition [10], and a Ru(bpy)32+ reaction with an N-(acyloxyl

Synthesis of racemic and chiral BEDT-TTF derivatives possessing hydroxy groups and their achiral and chiral charge transfer complexes

• Sara J. Krivickas,
• Chiho Hashimoto,
• Junya Yoshida,
• Akira Ueda,
• Kazuyuki Takahashi,
• John D. Wallis and
• Hatsumi Mori

Beilstein J. Org. Chem. 2015, 11, 1561–1569, doi:10.3762/bjoc.11.172

• ]. The trans-alkene 8 was reacted with trithione 7 under standard Diels–Alder cycloaddition conditions in refluxing toluene to afford a mixture of the trans-(S,S)- and (R,R)-9 in 56% yield (Scheme 1). The purchased alkene contained a small amount of the cis-isomer (trans-form:cis-form 96:4), but the cis

Tandem cross enyne metathesis (CEYM)–intramolecular Diels–Alder reaction (IMDAR). An easy entry to linear bicyclic scaffolds

• Javier Miró,
• María Sánchez-Roselló,
• Álvaro Sanz,
• Fernando Rabasa,
• Carlos del Pozo and
• Santos Fustero

Beilstein J. Org. Chem. 2015, 11, 1486–1493, doi:10.3762/bjoc.11.161

• explains why most of the reported examples that combine a CEYM reaction with a Diels–Alder cycloaddition in a tandem manner involve the use of ethylene as the olefin partner either by employing an internal source of it or by bubbling it into the reaction mixture. This strategy allowed for the synthesis of

Glycoluril–tetrathiafulvalene molecular clips: on the influence of electronic and spatial properties for binding neutral accepting guests

• Yoann Cotelle,
• Marie Hardouin-Lerouge,
• Stéphanie Legoupy,
• Olivier Alévêque,
• Eric Levillain and
• Piétrick Hudhomme

Beilstein J. Org. Chem. 2015, 11, 1023–1036, doi:10.3762/bjoc.11.115

• a glycoluril-based framework possessing quinone moieties for developing a Diels–Alder cycloaddition strategy. Thus compound 12 [33] was prepared in 73% yield by treatment with an excess of hydroquinone in 1,2-dichloroethane using a Friedel–Crafts alkylation as an electrophilic aromatic substitution

• onto compound 11 [34]. The hydroquinone moieties were subjected to a dehydrogenation reaction using DDQ in THF to reach desired glycolurildiquinone 13 [35] in 91% yield. The Diels–Alder cycloaddition was carried out by treatment of bis-dienophile 13 with TTF derivative 14 [36], able to give rise in

Recent advances in the electrochemical construction of heterocycles

• Robert Francke

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

• model compounds via electrochemically induced Diels–Alder cycloaddition. Cycloaddition of anodically generated N-acyliminium species 58 with olefins and alkynes. Electrochemical aziridination of olefins. Proposed mechanism for the aziridination reaction. Electrochemical synthesis of benzofuran and

Design and synthesis of novel bis-annulated caged polycycles via ring-closing metathesis: pushpakenediol

• Sambasivarao Kotha and
• Mirtunjay Kumar Dipak

Beilstein J. Org. Chem. 2014, 10, 2664–2670, doi:10.3762/bjoc.10.280

• rearrangement, a ring-closing metathesis (RCM) and an alkenyl Grignard addition. The introduction of olefinic moieties in the pentacycloundecane (PCUD) framework at appropriate positions followed by RCM led to the formation of novel heptacyclic cage systems. Keywords: Diels–Alder cycloaddition; Grignard

N–O Cleavage reactions of heterobicycloalkene-fused 2-isoxazolines

• Jaipal R. Nagireddy,
• Geoffrey K. Tranmer,
• Emily Carlson and
• William Tam

Beilstein J. Org. Chem. 2014, 10, 2200–2205, doi:10.3762/bjoc.10.227

• these compounds (17, 18 and 19) was prepared in our laboratories by a combination of Diels–Alder cycloaddition and 1,3-dipolar cycloaddition reactions [21]. We found that the Raney nickel-mediated cleavage took place readily on 17 to yield a β-hydroxyketo-functionalized 7-oxanorbornane 20 (Scheme 3

Boron-substituted 1,3-dienes and heterodienes as key elements in multicomponent processes

• Ludovic Eberlin,
• Fabien Tripoteau,
• François Carreaux,
• Andrew Whiting and
• Bertrand Carboni

Beilstein J. Org. Chem. 2014, 10, 237–250, doi:10.3762/bjoc.10.19

• based on a first Diels–Alder cycloaddition, as shown above. However, a recent report of Norsikian, Beau and co-workers described a novel sequence of tandem transformations which combined the Petasis reaction, intramolecular [4 + 2]-cycloaddition, cross metathesis and Michael reaction. This process gave

• . It was engaged in a one pot Diels–Alder cycloaddition with N-phenylmaleimide in the presence of various aldehydes to afford diols 39 as major diastereisomers (>95%) and in good overall yields (four steps) (Scheme 27). Conclusion Despite the synthetic potential of the boron-substituted 1,3-dienes and

Synthesis of five- and six-membered cyclic organic peroxides: Key transformations into peroxide ring-retaining products

• Alexander O. Terent'ev,
• Dmitry A. Borisov,
• Vera A. Vil’ and
• Valery M. Dembitsky

Beilstein J. Org. Chem. 2014, 10, 34–114, doi:10.3762/bjoc.10.6

Synthesis of the spiroketal core of integramycin

• Evgeny. V. Prusov

Beilstein J. Org. Chem. 2013, 9, 2446–2450, doi:10.3762/bjoc.9.282

• by an intramolecular Diels–Alder cycloaddition. The installation of the tetramic acid moiety would proceed via Lassey–Dickmann condensation with subsequent introduction of the 5-hydroxy group by oxidation of the corresponding vinylogous enolate. Herein a straightforward synthesis of the C16–C35

Sequential Diels–Alder/[3,3]-sigmatropic rearrangement reactions of β-nitrostyrene with 3-methyl-1,3-pentadiene

• Peter A. Wade,
• Alma Pipic,
• Matthias Zeller and
• Panagiota Tsetsakos

Beilstein J. Org. Chem. 2013, 9, 2137–2146, doi:10.3762/bjoc.9.251

• , tin(IV)-catalyzed nitronic ester cycloaddition and subsequent [3,3]-sigmatropic rearrangement is a superior method to direct thermal Diels–Alder cycloaddition as a means of obtaining pure nitro compound 18. In the rearrangement of nitronic ester 3, more stringent conditions are required and two

Flow photochemistry: Old light through new windows

• Jonathan P. Knowles,
• Luke D. Elliott and
• Kevin I. Booker-Milburn

Beilstein J. Org. Chem. 2012, 8, 2025–2052, doi:10.3762/bjoc.8.229

• by Aggarwal et al. to scale up the photochemical generation of a thioaldehyde 85 (Scheme 28) [81]. The in situ generated species underwent spontaneous Diels–Alder cycloaddition in the presence of cyclopentadiene. The reaction was performed on 18.2 g (60 mmol) of phenacyl sulfide 84 under batch

Alkoxide-induced ring opening of bicyclic 2-vinylcyclobutanones: A convenient synthesis of 2-vinyl-substituted 3-cycloalkene-1-carboxylic acid esters

• Xiufang Ji,
• Zhiming Li,
• Quanrui Wang and
• Andreas Goeke

Beilstein J. Org. Chem. 2012, 8, 650–657, doi:10.3762/bjoc.8.72

• proceeds by a two-step process, involving an initial hetero Diels–Alder cycloaddition of the diene and the ketene carbonyl group, followed by a [3,3]-sigmatropic (Claisen) rearrangement [25][26]. The most effective conditions were achieved by the employment of a slightly excessive amount of olefins 1. The

Recent developments in gold-catalyzed cycloaddition reactions

• Fernando López and
• José L. Mascareñas

Beilstein J. Org. Chem. 2011, 7, 1075–1094, doi:10.3762/bjoc.7.124

• with alkenes [70]. Gold-catalyzed intermolecular hetero-dehydro Diels–Alder cycloaddition [72]. Gold(I)-catalyzed stereoselective olefin cyclopropanation [74]. Reaction of propargylic benzoates with α,β-unsaturated imines to give azepine cycloadducts [77]. Gold-catalyzed (3 + 3) annulation of

One-pot Diels–Alder cycloaddition/gold(I)-catalyzed 6-endo-dig cyclization for the synthesis of the complex bicyclo[3.3.1]alkenone framework

• Boubacar Sow,
• Gabriel Bellavance,
• Francis Barabé and
• Louis Barriault

Beilstein J. Org. Chem. 2011, 7, 1007–1013, doi:10.3762/bjoc.7.114

• ) are underway and will be reported in due course. Structures of naturally occurring PPAPs. Gold(I)-catalyzed 6-endo-dig cyclization. Synthesis of papuaforin A core 4. Proposed domino Diels–Alder reaction/gold(I)-catalyzed cyclization. One-pot Diels–Alder cycloaddition/gold(I) catalyzed carbocyclization

• . Results of the one-pot Diels–Alder reaction/Au(I)-catalyzed cyclization. One-pot Diels–Alder cycloaddition/Au(I)-catalyzed carbocyclization of internal alkynes. Supporting Information Supporting Information File 179: Experimental procedures, characterization data, 1H NMR and 13C NMR spectra. Supporting