A new manganese-mediated, cobalt-catalyzed three-component synthesis of (diarylmethyl)sulfonamides

• Antoine Pignon,
• Erwan Le Gall and
• Thierry Martens

Beilstein J. Org. Chem. 2014, 10, 425–431, doi:10.3762/bjoc.10.39

• related compounds by a new manganese-mediated, cobalt-catalyzed three-component reaction between sulfonamides, carbonyl compounds and organic bromides is described. This organometallic Mannich-like process allows the formation of the coupling products within minutes at room temperature. A possible

• mechanism, emphasizing the crucial role of manganese is proposed. Keywords: carbonyl compounds; cobalt; manganese; multicomponent reaction; organic bromides; sulfonamides; Introduction (Diarylmethyl)amines constitute an important class of pharmacologically active compounds, displaying e.g. antihistaminic

• and versatility of multicomponent procedures, we describe herein a new manganese-mediated, cobalt-catalyzed three-component reaction, which circumvents the above-mentioned limitations by allowing the synthesis of an extended range of (diarylmethyl)sulfonamides (and related compounds) within minutes at

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

• was produced from 5. If the [4 + 2]-cycloadduct 9 was obtained with N-phenylmaleimide, it failed to give homoallylic alcohols, probably due to steric hindrance [42]. An elegant three-component process was developed by Hilt and co-workers using a cobalt-catalyzed Diels–Alder reaction as the key step in

• -phenylmaleimide and 4-phenyltriazoline-3,5-dione. Asymmetric synthesis of a α-hydroxyalkylcyclohexane. Tandem [4 + 2]-cycloaddition/allylboration of 3-silyloxy- and 4-alkoxy-dienyl boronates. Metal-mediated cycloisomerization/Diels–Alder reaction/allylboration sequence. Cobalt-catalyzed Diels–Alder/allylboration

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

• the Co(II)/Et3SiH/O2 system (Isayama–Mukaiyama reaction) Peroxysilylation of alkenes with molecular oxygen in the presence of triethylsilane catalyzed by cobalt(II) diketonates was described for the first time by S. Isayama and T. Mukaiyama in 1989 [246][247]. Currently, this approach is one of the

• -dicyclohexenylpropan-2-yl acetate (56) catalyzed by cobalt complexed with 2,2,6,6-tetramethylheptane-3,5-dione (Co(THD)2) as the first step giving 1,3-bis(1-(triethylsilylperoxy)cyclohexyl)propan-2-yl acetate (57) that was subsequently transformed into the carbonyl-containing diperoxide (1,3-bis(1-(triethylsilylperoxy

• , desilylation, and recyclization accompanied by a ring opening of oxirane or oxetane (Scheme 62 and Scheme 63). Cobalt(II) acetylacetonate (acac) or bis-2,2,6,6-tetramethylheptane-3,5-dienoate (thd) were used as the catalyst for the peroxidation of 219. The cyclization of the intermediate peroxide 220 was

Recent advances in transition metal-catalyzed Csp²-monofluoro-, difluoro-, perfluoromethylation and trifluoromethylthiolation

• Grégory Landelle,
• Armen Panossian,
• Sergiy Pazenok,
• Jean-Pierre Vors and
• Frédéric R. Leroux

Beilstein J. Org. Chem. 2013, 9, 2476–2536, doi:10.3762/bjoc.9.287

• ]. In the same paper, the authors showed that cobalt perchlorate could also improve the yield of the uncatalyzed reaction. Iron sulfate, on the other hand, gave the same yield as in the absence of added metals. 4 Catalytic trifluoromethylthiolation Aryl trifluoromethyl sulfides (ArSCF3) play an

An overview of the synthetic routes to the best selling drugs containing 6-membered heterocycles

• Marcus Baumann and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2013, 9, 2265–2319, doi:10.3762/bjoc.9.265

• pyridine structural class. Pyridine itself is produced industrially by either the traditional Chichibabin pyridine synthesis (Scheme 1, A), the Bönnemann reaction, a cobalt-catalysed cyclotrimerisation of alkynes and nitriles (Scheme 1, B) or the aerobic gas-phase condensation of croton aldehyde

• crude material in the subsequent Knoevenagel condensation with thiazolidinedione 1.68. In order to reduce the intermediate benzylidene double bond in this example sodium borohydride is used in the presence of cobalt chloride efficiently delivering pioglitazone in high purity. Other syntheses of

Flexible synthesis of anthracycline aglycone mimics via domino carbopalladation reactions

• Markus Leibeling and
• Daniel B. Werz

Beilstein J. Org. Chem. 2013, 9, 2194–2201, doi:10.3762/bjoc.9.258

• in 88% overall yield (over two steps). Another approach to non-linear systems utilizes a cobalt-mediated intramolecular [2 + 2 + 2]-cycloaddition of a triyne system 9 leading to the fourfold annulated ring system 10 in only one step [16]. Late stage functionalization led to the anticipated structural

A concise enantioselective synthesis of the guaiane sesquiterpene (−)-oxyphyllol

• Martin Zahel and
• Peter Metz

Beilstein J. Org. Chem. 2013, 9, 2028–2032, doi:10.3762/bjoc.9.239

• , 977 cm−1; GC–MS: m/z = 296 [M]+; anal. calcd for C15H20O4S: C 60.79, H 6.80; found: C 60.88, H 6.92. Alcohol 3: Epoxide 4 (100.0 mg, 454 μmol) and cobalt(II) acetylacetonate (23.3 mg, 91 μmol) were dissolved in THF (5 mL), and the solution was cooled to 0 °C. Oxygen was bubbled through the solution

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

• ][29][30][31]. Previously, we also reported the synthesis of cobalt-containing SPO ligands and their palladium complex. This was successfully applied as a catalytic precursor in oxidative Heck reactions [32]. However, these reactions were carried out at high temperatures with limited substrate scope

Spin state switching in iron coordination compounds

• Philipp Gütlich,
• Ana B. Gaspar and
• Yann Garcia

Beilstein J. Org. Chem. 2013, 9, 342–391, doi:10.3762/bjoc.9.39

• further examples of iron(II) SCO compounds have been published [7][8][9][10][11][12][13][16][17][18][19][20][21][22][23][24][25][26][27][28], and other coordination compounds of 3d transition elements such as cobalt(II) [29][30], and to a much lesser extent cobalt(III), chromium(II), manganese(II

• )↔t2g3eg2 (6A1g, HS). ΔrHL is even less pronounced in cobalt(II) SCO compounds (ΔrHL ≤ 10 pm) with ΔS = 1 transitions between the electron configurations t2g6eg1 (2Eg, LS)↔t2g5eg2 (4T1g, HS), because only one electron is transferred from antibonding eg* to t2g orbitals. The size of ΔrHL is important for the

• research than has NMR. SCO compounds of iron(III), iron(II), and cobalt(II), which are the 3d transition metal elements most actively studied with EPR, typically reveal characteristic spectra that are sufficiently well resolved in both HS and LS states. There is no spin–orbit coupling in SCO compounds of

Recent advances in transition-metal-catalyzed intermolecular carbomagnesiation and carbozincation

• Kei Murakami and
• Hideki Yorimitsu

Beilstein J. Org. Chem. 2013, 9, 278–302, doi:10.3762/bjoc.9.34

• ). Recently, iron and cobalt have been regarded as efficient catalysts for carbometalation of simple alkynes. Shirakawa and Hayashi reported that iron salts could catalyze arylmagnesiation of arylacetylenes in the presence of an N-heterocyclic carbene (NHC) ligand (Scheme 29) [103]. In 2012, Shirakawa and

• efficiently with good stereoselectivity (Scheme 33). A more versatile arylmetalation of dialkylacetylenes using arylzinc reagents in the presence of a cobalt catalyst was then reported by Yorimitsu and Oshima (Scheme 34, top) [115]. Treatment of dialkylacetylenes with arylzinc reagents in acetonitrile in the

• presence of a catalytic amount of cobalt bromide afforded the corresponding arylated intermediate 4e. Further study by Yoshikai revealed that the use of Xantphos as a ligand totally changed the products [116]. Smooth 1,4-hydride migration from 4A to 4B happened to provide organozinc 4f (Scheme 34, bottom

Tandem aldehyde–alkyne–amine coupling/cycloisomerization: A new synthesis of coumarins

• Maddi Sridhar Reddy,
• Nuligonda Thirupathi and
• Madala Haribabu

Beilstein J. Org. Chem. 2013, 9, 180–184, doi:10.3762/bjoc.9.21

• , cobalt, iridium and iron. Similarly, cycloisomerization of alkynols and alkynamines has also been an attractive approach for the synthesis of various known and new heterocyclic frameworks [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]. Various alkynophilic catalysts such as

Copper-catalyzed CuAAC/intramolecular C–H arylation sequence: Synthesis of annulated 1,2,3-triazoles

• Rajkumar Jeyachandran,
• Harish Kumar Potukuchi and
• Lutz Ackermann

Beilstein J. Org. Chem. 2012, 8, 1771–1777, doi:10.3762/bjoc.8.202

• ][16]. This streamlining of organic synthesis has predominantly been accomplished with palladium [4][5][6][7][8][9][10][11][12][13][14][15][16], rhodium [17][18][19] or ruthenium [20][21][22] complexes [4][5][6][7][8][9][10][11][12][13][14][15][16]. However, less expensive nickel, cobalt, iron or

C2-Alkylation of N-pyrimidylindole with vinylsilane via cobalt-catalyzed C–H bond activation

• Zhenhua Ding and
• Naohiko Yoshikai

Beilstein J. Org. Chem. 2012, 8, 1536–1542, doi:10.3762/bjoc.8.174

• with a vinylsilane was achieved by using a cobalt catalyst generated in situ from CoBr2, bathocuproine, and cyclohexylmagnesium bromide. The reaction allows coupling between a series of N-pyrimidylindoles and vinylsilanes at a mild reaction temperature of 60 °C, affording the corresponding alkylated

• indoles in moderate to good yields. Keywords: alkylation; C–H functionalization; cobalt; indole; vinylsilane; Introduction The indole ring ubiquitously occurs in biologically active natural and unnatural compounds [1][2][3]. Consequently, there has been a strong demand for catalytic methods allowing

• palladium-catalyzed, norbornene-mediated C2-alkylation reaction with a broad spectrum of alkyl bromides [21]. Over the past few years, our group and others have explored C–H bond functionalization reactions using cobalt complexes as inexpensive transition-metal catalysts [22], which often feature mild

Synthesis of highly functionalized β-aminocyclopentanecarboxylate stereoisomers by reductive ring opening reaction of isoxazolines

• Melinda Nonn,
• Loránd Kiss,
• Reijo Sillanpää and
• Ferenc Fülöp

Beilstein J. Org. Chem. 2012, 8, 100–106, doi:10.3762/bjoc.8.10

•  3). Combinations of NaBH4 (as a mild and selective reducing agent) with cobalt, nickel, iridium or rhodium halide have previously been employed for cleavage of the isoxazoline ring system, which is otherwise inert to NaBH4 without such metal halide additives [50]. Accordingly, we investigated 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

• , cobalt, nickel or palladium catalysts [4]. In recent years, however, platinum and particularly gold complexes have also emerged as excellent catalysts for the promotion of novel types of cycloaddition reactions, usually involving non-activated unsaturated systems (e.g., alkynes, allenes, alkenes or 1,3

A practical route to tertiary diarylmethylamides or -carbamates from imines, organozinc reagents and acyl chlorides or chloroformates

• Erwan Le Gall,
• Antoine Pignon and
• Thierry Martens

Beilstein J. Org. Chem. 2011, 7, 997–1002, doi:10.3762/bjoc.7.112

• , prepared in parallel via a cobalt-catalyzed procedure [36] was added and the resulting solution was stirred for 30 minutes at ambient temperature. The chromatographic purification of the crude oil afforded the expected diarylmethylamide or -carbamate 4. Representative experimental results are reported in

• continuous stirring. The aryl bromide (15 mmol) and anhydrous cobalt bromide (330 mg) were then added to the mixture, which was stirred at rt for additional 20 min. Stirring was then stopped and the surrounding solution was taken-up with a syringe. The solution was then added to the flask containing the

Nano copper oxide catalyzed synthesis of symmetrical diaryl sulfides under ligand free conditions

• K. Harsha Vardhan Reddy,
• V. Prakash Reddy,
• A. Ashwan Kumar,
• G. Kranthi and
• Y.V.D. Nageswar

Beilstein J. Org. Chem. 2011, 7, 886–891, doi:10.3762/bjoc.7.101

• cobalt [42] have been used in cross-coupling reactions, developed for the formation of carbon–sulfur bonds. Most of these coupling protocols involve the reaction between thiols and aryl halides, resulting in the formation of C–S bonds. Most of these metal-catalyzed reactions involve volatile and foul

Gold-catalyzed propargylic substitutions: Scope and synthetic developments

• Olivier Debleds,
• Eric Gayon,
• Emmanuel Vrancken and
• Jean-Marc Campagne

Beilstein J. Org. Chem. 2011, 7, 866–877, doi:10.3762/bjoc.7.99

• of a cobalt complex. In 1994, Murahashi [8] described in a seminal paper the propargylic substitution of monosubstituted alkynes bearing a good leaving group on the propargylic alcohol moiety, where a mechanism through a copper-allenylidene intermediate was postulated. Subsequently, asymmetric

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

Achiral bis-imine in combination with CoCl₂: A remarkable effect on enantioselectivity of lipase-mediated acetylation of racemic secondary alcohol

• K. Arunkumar,
• M. Appi Reddy,
• T. Sravan Kumar,
• B. Vijaya Kumar,
• K. B. Chandrasekhar,
• P. Rajender Kumar and
• Manojit Pal

Beilstein J. Org. Chem. 2010, 6, 1174–1179, doi:10.3762/bjoc.6.134

• acetylation of the (R)-isomer of a racemic benzylic secondary alcohol with 91% ees. The methodology was used for the preparation of the known drug rivastigmine. Keywords: acetylation; bis-imine; cobalt chloride; enantioselectivity; lipase; Introduction The development and use of newer synthetic methods for

Miniemulsion polymerization as a versatile tool for the synthesis of functionalized polymers

• Daniel Crespy and
• Katharina Landfester

Beilstein J. Org. Chem. 2010, 6, 1132–1148, doi:10.3762/bjoc.6.130

• diacrylate to yield, after the transfer to water, stable microgels. Monodisperse latexes could be obtained with the poly(2-hydroxyethyl methacrylate) when water, methanol, ethanol, ethylene glycol, or water/ethanol mixtures were used as the dispersed phase in the presence of cobalt tetrafluoroborate [21

• ]. This approach is particularly interesting to encapsulate large amounts of metal salts. Indeed, up to 22.6 wt % of the cobalt salt compared to the monomer content could be encapsulated. Monodisperse latexes of silver–polymer particles were also obtained upon reduction of silver nitrate in the monomer

• polystyrene nanoparticles were synthesized in emulsion and miniemulsion by non-covalently immobilized metallocene catalysts [67]. The catalytic polymerization of butadiene with a cobalt catalyst was found to give highly crystalline 1,2-polybutadiene with a particle size of 150–200 nm [68]. The

Cross-metathesis of allylcarboranes with O-allylcyclodextrins

• Ivan Šnajdr,
• Zbyněk Janoušek,
• Jindřich Jindřich and
• Martin Kotora

Beilstein J. Org. Chem. 2010, 6, 1099–1105, doi:10.3762/bjoc.6.126

• (C88H126O5510B2B8Na2). Per-O-acetyl-2I-O-{4-{8,8’-μ-(sulfido)-[3,3’-commo-cobalt(III)-bis-(1,2-dicarbaundecaborate)]-8-yl}but-2-en-1-yl}-β-cyclodextrin (3ba). The compound was prepared from 2a (0.15 g, 0.07 mmol) and 1b (20 mg, 0.05 mmol). Column chromatography gave the title compound, 0.023 g (18%), as an orange

• , B-7’, B-9, B-9’, B-11, B-11’, B-12, B-12’), −14.68 (bs, 2 B, B-6, B-6’); MS (EI, m/z (rel.%)): 1214.4 (100), 1010.3 (10), 413.3 (68), 391.3 (10), 307.2 (52); HR-MS (ESI) calcd. for C90H135O5510B3B15CoNa2S: 1213.9194, found 1213.9233. Per-O-acetyl-6I-O-{4-{8,8’-μ-(sulfido)-[3,3’-commo-cobalt(III)-bis

• (bs, 2 B, B-6, B-6’); MS (EI, m/z (rel.%)): 1214.1 (100), 1010.3 (10), 414.3 (52), 360.3 (10), 307.2 (96); HR-MS (ESI) calcd. for C90H135O5510B3B15CoNa2S: 1213.9194, found 1213.9234. Per-O-acetyl-2I-O-{4-{8,8’-μ-(disulfido)-[3,3’-commo-cobalt(III)-bis-(1,2-dicarbaundecaborate)]-8-yl}but-2-en-1-yl}-β

A perfluorocyclopentene based diarylethene bearing two terpyridine moieties – synthesis, photochemical properties and influence of transition metal ions

• Falk Wehmeier and
• Jochen Mattay

Beilstein J. Org. Chem. 2010, 6, No. 53, doi:10.3762/bjoc.6.53

• contrast to the iron(II) complex, the ditopic ligand seems to retain its photochromic properties in the cobalt(II) and nickel(II) complexes – synthesized from CoCl2 and [Ni(acac)2], respectively – although the photocyclisation takes much longer than with free 10a (about 5 minutes compared to ca. 30 seconds

• reversibility. It was shown that the presence of various transition metal ions significantly influences the photochromism of the bridging unit: While iron(II)-ions completely inhibit the photochromic reaction, cobalt(II) and nickel(II) appear to slow down the photoreaction considerably. Zinc(II)-ions, on the

• dissolved. The formation of the iron(II) and cobalt(II) complexes can be traced by the color change from colorless to blue (iron(II)) and red (cobalt(II)), respectively. UV–vis-spectra of 10a before (solid), after UV-irradiation (dashed) and after irradiation with vis light (dotted). UV–vis-spectra of 12

Molecular recognition of organic ammonium ions in solution using synthetic receptors

• Andreas Späth and
• Burkhard König

Beilstein J. Org. Chem. 2010, 6, No. 32, doi:10.3762/bjoc.6.32

Prediction of reduction potentials from calculated electron affinities for metal-salen compounds

• Sarah B. Bateni,
• Kellie R. England,
• Anthony T. Galatti,
• Handeep Kaur,
• Victor A. Mendiola,
• Alexander R. Mitchell,
• Michael H. Vu,
• Benjamin F. Gherman and
• James A. Miranda

Beilstein J. Org. Chem. 2009, 5, No. 82, doi:10.3762/bjoc.5.82

• [10] for both sets of metal-salens. Results and Discussion The 19 metal-salens comprising the training set are shown in Figure 1. The metals used in the training set include nickel, cobalt, copper, iron, zinc, and palladium. Included in the training set are the parent metal-salens (no substitution

• , cobalt, and copper were plotted on the graph due to the other metals (iron, zinc, and palladium) having only one point each in the training set. Negative Hammett parameters result from the presence of electron-donating groups and lead to smaller EAs. Positive Hammett parameters result from the presence

• of electron-withdrawing groups and lead to larger EAs. Figure 3 shows that there is a good linear correlation between the experimental reduction potential (Epc) and EA for each of nickel, cobalt, and copper. Iron, zinc, and palladium were again excluded due to having only one point each in the