Oxidative phenylamination of 5-substituted 1-hydroxynaphthalenes to N-phenyl-1,4-naphthoquinone monoimines by air and light “on water”

• Julio Benites,
• Juan Meléndez,
• Cynthia Estela,
• David Ríos,
• Luis Espinoza,
• Iván Brito and
• Jaime A. Valderrama

Beilstein J. Org. Chem. 2014, 10, 2448–2452, doi:10.3762/bjoc.10.255

• conventional oxidative phenylamination procedures, this novel synthetic method offers the advantage of aerobic conditions “on water” instead of hazardous oxidant reagents currently employed in aqueous alcoholic media. Keywords: 1,4-naphthoquinone monoimines; on water; oxidative coupling; rose bengal; solar

• green route for the preparation of N-phenyl-1,4-naphthoquinone monoimines by on-water oxidative coupling reaction of 1-hydroxynaphthalene derivatives with oxygen-substituted phenylamines under solar light or green LEDs radiation, rose bengal as singlet oxygen sensitizer and aerobic conditions. Results

• histidine, compound 6 was obtained in 69 and 62% yield, respectively. By comparing these results to that observed in the absence of histidine, it may be suggested that singlet oxygen is involved in the oxidative coupling reaction to produce compound 6. In addition, experiments on the oxidative coupling

Oligomerization of optically active N-(4-hydroxyphenyl)mandelamide in the presence of β-cyclodextrin and the minor role of chirality

• Helmut Ritter,
• Antonia Stöhr and
• Philippe Favresse

Beilstein J. Org. Chem. 2014, 10, 2361–2366, doi:10.3762/bjoc.10.246

• ; enzyme; oxidative coupling; phenol oligomer; Introduction Lignin consists of mechanical stabilizing polyphenols and thus plays an important role in many plants [1][2]. For the in vitro synthesis of polyphenols via oxidative coupling reactions, laccases and peroxidases are suitable enzymes to catalyze

• the oligomerization of substituted electron-rich phenols in the presence of oxidizing agents [3][4]. In addition to that, N,N'-bis(salicylidene)ethylenediamine-iron(II) (iron(II)-salen) represents an alternative catalyst for oxidative coupling reactions of phenol derivatives [5]. The use of β

• -cyclodextrin (CD) allows the oxidative coupling of poor water soluble phenol derivatives via complexation without using of organic solvents [6][7][8]. However, to the best of our knowledge, there were no studies published dealing with the potential enantioselective control of enzyme catalyzed oligomerization

cis–trans Isomerization of silybins A and B

• Michaela Novotná,
• Radek Gažák,
• David Biedermann,
• Florent Di Meo,
• Petr Marhol,
• Marek Kuzma,
• Lucie Bednárová,
• Kateřina Fuksová,
• Patrick Trouillas and
• Vladimír Křen

Beilstein J. Org. Chem. 2014, 10, 1047–1063, doi:10.3762/bjoc.10.105

• configuration is known [1][2] and their separation was accomplished recently [3][4][5]. Both silybin isomers as well as other flavonolignans from silymarin (crude defatted extract from the fruits of S. marianum) are products of a phenolic oxidative coupling of the flavonoid taxifolin and the lignan coniferyl

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

• -dioxanes Modern approaches to the synthesis of 1,2-dioxanes are based on reactions with singlet oxygen, the oxidative coupling of carbonyl compounds and alkenes in the presence of manganese and cerium salts, the co-oxidation of alkenes and thiols with oxygen, the Isayama–Mukaiyama peroxidation, the

• -dioxan-3-ol (202) and 6-(prop-1-en-2-yl)-1,2-dioxane-3-imine (204), containing the hydroxy and imine groups, respectively (Scheme 56) [304]. 3.2. Oxidative coupling of carbonyl compounds and alkenes in the presence of manganese or cerium salts The synthesis of 1,2-dioxanes 207 is based on the addition of

Advancements in the mechanistic understanding of the copper-catalyzed azide–alkyne cycloaddition

• Regina Berg and
• Bernd F. Straub

Beilstein J. Org. Chem. 2013, 9, 2715–2750, doi:10.3762/bjoc.9.308

• proteins from oxidative coupling [45][46]. However, the latter phosphine reagent should only be used in low quantities, as its binding to copper ions has an inhibitory effect. Another disadvantage of using TCEP is the consumption of the azide substrates in Staudinger reactions [56][57][58] with the

• (I) oxidation state in aqueous solution [14][64]. This is important as Cu(II) ions are harmful to this experiment in two ways: on the one hand, Cu(II) ions catalyze the oxidative coupling of the alkyne substrates to give diynes as undesired byproducts (Glaser coupling [9][10][11], Eglinton coupling

New developments in gold-catalyzed manipulation of inactivated alkenes

• Michel Chiarucci and
• Marco Bandini

Beilstein J. Org. Chem. 2013, 9, 2586–2614, doi:10.3762/bjoc.9.294

• ) followed by oxidative coupling of the formed alkylgold moiety with the ortho C–H bond of the tethered phenyl group. Compound 137 was finally obtained via reductive elimination of intermediate 141 (Scheme 34). The formal [3 + 2] annulation between the aniline moiety and the C–C double bond constitutes the

• counterparts, allowed an intermolecular variant to be successfully developed (Scheme 39a). A slight modification of the reaction conditions enabled to expand the oxidative coupling to a wider range of olefins. In particular the use of IBA (153) as the oxidant allowed substrates incompatible with Selectfluor

• terminal alkenes by bimetallic gold(I) catalysis in presence of Selectfluor. Proposed mechanism for the aminoarylation of alkenes via [Au(I)-Au(I)]/[Au(II)-Au(II)] redox catalysis. Oxyarylation of terminal olefins via redox gold catalysis. a) Intramolecular gold-catalyzed oxidative coupling reactions with

Iron-catalyzed decarboxylative alkenylation of cycloalkanes with arylvinyl carboxylic acids via a radical process

• Jincan Zhao,
• Hong Fang,
• Jianlin Han and
• Yi Pan

Beilstein J. Org. Chem. 2013, 9, 1718–1723, doi:10.3762/bjoc.9.197

• obtained. Based on these results and literature reports [69][70], a plausible mechanism for the radical oxidative coupling is illustrated in Scheme 3. At the beginning, Fe-catalyzed cleavage of DTBP by Fe(III) in the presence of cinnamic acid, gives tert-butoxy radical A, intermediate B and one acac. Next

Anodic coupling of carboxylic acids to electron-rich double bonds: A surprising non-Kolbe pathway to lactones

• Robert J. Perkins,
• Hai-Chao Xu,
• John M. Campbell and
• Kevin D. Moeller

Beilstein J. Org. Chem. 2013, 9, 1630–1636, doi:10.3762/bjoc.9.186

• reaction has been used to form dimers [12], as well as in some cases cyclic products (Scheme 3, reaction 2) [13][14][15]. However, the chemistry highlighted in Scheme 2 suggests that a Kolbe-type decarboxylation reaction might not interfere at all with an oxidative coupling reaction between a carboxylic

• 13, the product of a direct oxidative coupling between the carboxylic acid moiety and the electron-rich olefin. We report here that this is the case and that the direct oxidative coupling of a carboxylic acid and an electron-rich olefin can be accomplished in good yield. In all cases, the reactions

• . Radical cation stabilization by an o-methoxy substituent. General scheme for anodic cyclization reactions. Anodic cyclization competition study. Kolbe electrolysis reactions. Oxidative coupling between a carboxylic acid and electron-rich olefin. Predicted relative rates of single-electron oxidation based

Palladium(II)-catalyzed Heck reaction of aryl halides and arylboronic acids with olefins under mild conditions

• Tanveer Mahamadali Shaikh and
• Fung-E Hong

Beilstein J. Org. Chem. 2013, 9, 1578–1588, doi:10.3762/bjoc.9.180

• . Therefore, the development of an alternative general and mild procedure employing a stable and inexpensive ligand is still in great demand. Furthermore, the application of palladium complexes in the oxidative coupling of organo-boron compounds with olefins has attracted much attention in recent years [33

• product 3a in 62% yield (Table 2, entry 3). The oxidative coupling was found to be selective in the case of 4-bromostyrene (2b), which gives 90% yield of 4-bromo trans-stilbene (3b) without the observation of any side product (Table 2, entry 4). The presence of either an electron-withdrawing or electron

• as, -CH2OH, -CHO, -COCH3 -CN and -CF3 are rather useful in organic synthesis. However, in earlier reported oxidative coupling conditions these functional groups were not compatible and gave low yields of products. Therefore, these highly modifiable groups were screened under these catalytic

A reductive coupling strategy towards ripostatin A

• Kristin D. Schleicher and
• Timothy F. Jamison

Beilstein J. Org. Chem. 2013, 9, 1533–1550, doi:10.3762/bjoc.9.175

• laboratory [42][43], it is believed that epoxide oxidative addition precedes alkyne addition, as opposed to concerted oxidative coupling. At least when dimethylphenylphosphine is used as ligand, this may proceed via the intermediacy of a betaine species. In the reductive coupling reaction of enynes and

Study on the total synthesis of velbanamine: Chemoselective dioxygenation of alkenes with PIFA via a stop-and-flow strategy

• Huili Liu,
• Kuan Zheng,
• Xiang Lu,
• Xiaoxia Wang and
• Ran Hong

Beilstein J. Org. Chem. 2013, 9, 983–990, doi:10.3762/bjoc.9.113

• leukemia [12][13][14]. Fragmentation of 3 under acidic conditions delivers two structural units, desacetylvindoline and velbanamine (2) [15]. The reassembling of catharanthine (1) and vindoline (5) into the parent alkaloids 3 and 4 by using FeCl3-promoted oxidative coupling supports the biogenesis of

New enzymatically polymerized copolymers from 4-tert-butylphenol and 4-ferrocenylphenol and their modification and inclusion complexes with β-cyclodextrin

• Adam Mondrzyk,
• Beate Mondrzik,
• Sabrina Gingter and
• Helmut Ritter

Beilstein J. Org. Chem. 2012, 8, 2118–2123, doi:10.3762/bjoc.8.238

• (N3-β-CD) was carried out. The formation of inter- and intramolecular inclusion complexes was investigated by DLS measurement. Keywords: copolymer; ß-cyclodextrin; enzymatic polymerization; 4-ferrocenylphenol; polyphenol; 4-tert-butylphenol; horseradish peroxidase; HRP oxidative coupling; inclusion

Rh(III)-catalyzed directed C–H bond amidation of ferrocenes with isocyanates

• Satoshi Takebayashi,
• Tsubasa Shizuno,
• Takashi Otani and
• Takanori Shibata

Beilstein J. Org. Chem. 2012, 8, 1844–1848, doi:10.3762/bjoc.8.212

• enantioselective if chiral bisoxazoline ligands were used. However, the substrate scope of this reaction is narrow because of intramolecular reaction. More recently, chiral oxazoline-directed diastereoselective arylation of ferrocenes was reported based on a Pd(II)-catalyzed oxidative coupling reaction [8]. Most

Palladium-catalyzed dual C–H or N–H functionalization of unfunctionalized indole derivatives with alkenes and arenes

• Gianluigi Broggini,
• Egle M. Beccalli,
• Andrea Fasana and
• Silvia Gazzola

Beilstein J. Org. Chem. 2012, 8, 1730–1746, doi:10.3762/bjoc.8.198

• order to achieve reoxidation of the Pd(0) species to Pd(II). Intramolecular reactions involving arenes Intramolecular arylations by oxidative coupling were investigated by DeBoef and co-workers as a tool for synthesizing heteropolycyclic compounds [80]. The aerobic Pd(II)-catalyzed reaction of the N

• (Scheme 32) [79]. Indeed, the reaction carried out with 10 mol % of PdCl2(MeCN)2 as catalyst and a stoichiometric amount of 1,4-benzoquinone in DMF/THF as solvent underwent an oxidative cascade process involving the sequential intramolecular formation of C–N and C–C bonds, with an oxidative coupling

Synthesis of conformationally restricted glutamate and glutamine derivatives from carbonylation of orthopalladated phenylglycine derivatives

• Esteban P. Urriolabeitia,
• Eduardo Laga and
• Carlos Cativiela

Beilstein J. Org. Chem. 2012, 8, 1569–1575, doi:10.3762/bjoc.8.179

• processes and avoiding the obtainment of unwanted isomers. Probably the aspect of this method of synthesis with the greatest impact is the oxidative coupling of two C–H bonds to give a new C–C bond, because it avoids the use of prefunctionalized substrates, minimizes the amount of waste generated during the

Arylglycine-derivative synthesis via oxidative sp³ C–H functionalization of α-amino esters

• Zhanwei Xu,
• Xiaoqiang Yu,
• Xiujuan Feng and
• Ming Bao

Beilstein J. Org. Chem. 2012, 8, 1564–1568, doi:10.3762/bjoc.8.178

• Zhanwei Xu Xiaoqiang Yu Xiujuan Feng Ming Bao State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116023, China 10.3762/bjoc.8.178 Abstract An efficient method for the synthesis of arylglycine derivatives is described. The oxidative coupling reactions of naphthols and

• reported the copper-catalyzed oxidative coupling reaction of alkynes with tertiary amine N-oxides [15]. This new strategy for the direct functionalization of sp3 C–H bonds adjacent to a nitrogen atom, via tertiary amine N-oxide intermediates, was successfully applied to the coupling reaction of ethyl 2

• -1-yl)acetate (2b), and ethyl 2-(benzyl(methyl)amino)acetate (2c) proceeded smoothly to give the corresponding products 3a–3c in good yields (Table 2, entries 1–3, 64–79%). These results indicated that both α-cyclic and acyclic amino esters could be employed in this type oxidative coupling reaction

Sexithiophenes as efficient luminescence quenchers of quantum dots

• Christopher R. Mason,
• Yang Li,
• Paul O’Brien,
• Neil J. Findlay and
• Peter J. Skabara

Beilstein J. Org. Chem. 2011, 7, 1722–1731, doi:10.3762/bjoc.7.202

• study the role of the dimethylaminophenyl group on the oligothiophene properties. The synthesis of 2a and 2b was completed by following our published procedure [14], with oxidative coupling of 3a or 3b with the aid of FeCl3 affording sexithiophenes 2a and 2b in moderate yields (40% and 50%, respectively

Pseudo five-component synthesis of 2,5-di(hetero)arylthiophenes via a one-pot Sonogashira–Glaser cyclization sequence

• Dominik Urselmann,
• Dragutin Antovic and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2011, 7, 1499–1503, doi:10.3762/bjoc.7.174

• yields, resulting in an increased formation of byproducts already during the desilylation and the oxidative coupling step (as monitored by TLC). A lower reaction temperature resulted in a prolonged reaction time under microwave conditions to achieve complete conversion (Table 1, entry 5), whereas

Ugi post-condensation copper-triggered oxidative cascade towards pyrazoles

• Aurélie Dos Santos,
• Laurent El Kaim,
• Laurence Grimaud and
• Caroline Ronsseray

Beilstein J. Org. Chem. 2011, 7, 1310–1314, doi:10.3762/bjoc.7.153

• pyrazolidinone under oxidative conditions from simple hydrazone derivatives (Scheme 1) [13]. The cascade features a [3 + 2] cycloaddition coupled with an aerobic oxidation of the resulting pyrazolidine. A further oxidative coupling may be observed according to the substitution pattern of the starting acyl

Functionalization of heterocyclic compounds using polyfunctional magnesium and zinc reagents

• Paul Knochel,
• Matthias A. Schade,
• Sebastian Bernhardt,
• Georg Manolikakes,
• Albrecht Metzger,
• Fabian M. Piller,
• Christoph J. Rohbogner and
• Marc Mosrin

Beilstein J. Org. Chem. 2011, 7, 1261–1277, doi:10.3762/bjoc.7.147

• chloranil amidocuprate 87 undergoes an oxidative coupling providing the adenine derivative 88 in 71% yield. A treatment with D-valinol (89) affords the desired CDK inhibitor, purvalanol A (84) in 65% yield (Scheme 15) [44]. 2.2 The preparation of polyfunctional heterocyclic magnesium reagents by the

Use of mixed Li/K metal TMP amide (LiNK chemistry) for the synthesis of [2.2]metacyclophanes

• Marco Blangetti,
• Patricia Fleming and
• Donal F. O'Shea

Beilstein J. Org. Chem. 2011, 7, 1249–1254, doi:10.3762/bjoc.7.145

• oxidative coupling with 1,2-dibromoethane. The synthetic ease of this approach compares favourably with previously reported methods and allows for ready access to potentially useful planar chiral derivatives. Keywords: benzylic metalation; LiNK chemistry; [2.2]metacyclophane; oxidative coupling; planar

• ]. We envisaged that our LiNK metalation conditions with in situ oxidative coupling could offer a facile general approach to [2.2]metacyclophanes, which would be of general synthetic interest (Scheme 2). Oxidative homo-coupling of benzyl anions has previously been noted, but it has remained relatively

• unexplored as a synthetic procedure [22][23][24]. We speculated that if oxidative coupling of the benzyl metalated xylenes 5 could be achieved to form the open dimer 6, then a second metalation and oxidative ring closure would yield the [2.2]metacyclophanes 8. A stepwise approach, as shown in Scheme 2, could

Novel carbazole–pyridine copolymers by an economical method: synthesis, spectroscopic and thermochemical studies

• Aamer Saeed,
• Madiha Irfan and
• Shahid Ameen Samra

Beilstein J. Org. Chem. 2011, 7, 638–647, doi:10.3762/bjoc.7.75

• of the pyridine ring [20]. Zheng et al. have prepared a new class of copolymers that incorporate pyridine and N-alkyl carbazole alternatively into the main chain by oxidative-coupling copolymerization. These polymers are thermostable, highly soluble, and processable, and the fluorescence spectra of

Gold catalysis for organic synthesis

• F. Dean Toste

Beilstein J. Org. Chem. 2011, 7, 553–554, doi:10.3762/bjoc.7.63

• , cycloaddition and cycloisomerization reactions, to applications in enantioselective catalysis, oxidative coupling and the total synthesis of natural products, and transformations of alkynes, allenes, alkenes and even C–H bonds. A true treasure chest of reactivity! I am grateful to all of the authors that have

An overview of the key routes to the best selling 5-membered ring heterocyclic pharmaceuticals

• Marcus Baumann,
• Ian R. Baxendale,
• Steven V. Ley and
• Nikzad Nikbin

Beilstein J. Org. Chem. 2011, 7, 442–495, doi:10.3762/bjoc.7.57

Redox-active tetrathiafulvalene and dithiolene compounds derived from allylic 1,4-diol rearrangement products of disubstituted 1,3-dithiole derivatives

• Filipe Vilela,
• Peter J. Skabara,
• Christopher R. Mason,
• Thomas D. J. Westgate,
• Asun Luquin,
• Simon J. Coles and
• Michael B. Hursthouse

Beilstein J. Org. Chem. 2010, 6, 1002–1014, doi:10.3762/bjoc.6.113

• -oxidative coupling of 3 and 27 is therefore only accessible through the pendant group making a dimer the only possible product. Compounds 25 and 28 have two oxidisable pendant thiophene groups, so polymerisation could theoretically proceed through the coupling of these units. However, repeated cycling over