Diastereoselective and enantioselective conjugate addition reactions utilizing α,β-unsaturated amides and lactams

• Katherine M. Byrd

Beilstein J. Org. Chem. 2015, 11, 530–562, doi:10.3762/bjoc.11.60

• ). Molander and Harris developed the samarium(II) iodide-mediated cyclization of α,β-unsaturated esters and amides [167] (Scheme 20). Previous methods for the cyclization of alkyl halides and α,β-unsaturated carbonyl systems include: (1) tin-mediated radical cyclization [168] or (2) nucleophilc cyclization

Efficient deprotection of F-BODIPY derivatives: removal of BF₂ using Brønsted acids

• Mingfeng Yu,
• Joseph K.-H. Wong,
• Cyril Tang,
• Peter Turner,
• Matthew H. Todd and
• Peter J. Rutledge

Beilstein J. Org. Chem. 2015, 11, 37–41, doi:10.3762/bjoc.11.6

• tin or zinc have been investigated [13][14]. More recently, the F-BODIPY motif has been envisaged as a means of protecting the dipyrrin, to enable chemical modification and purification before removal of the BF2 unit (i.e., deprotection) to reveal the functionalized dipyrrin. With this goal in mind

The Shono-type electroorganic oxidation of unfunctionalised amides. Carbon–carbon bond formation via electrogenerated N-acyliminium ions

• Alan M. Jones and
• Craig E. Banks

Beilstein J. Org. Chem. 2014, 10, 3056–3072, doi:10.3762/bjoc.10.323

• of the generated reactive intermediates and assist in the formation of the desired products. Tin, silicon or sulfur-based electroauxiliaries have proved useful in this endeavour. Yoshida and co-workers developed an organothio electroauxiliary that is selectively cleaved under anodic oxidation

• conditions [32][33]. Although the introduction of an electroauxiliary requires an additional synthetic step to prepare, the resulting carbon–tin, carbon–silicon or carbon–sulfur bond has a less positive oxidation potential than an unfunctionalised carbamate. Therefore, exquisite control can be exerted on the

Solution processable diketopyrrolopyrrole (DPP) cored small molecules with BODIPY end groups as novel donors for organic solar cells

• Diego Cortizo-Lacalle,
• Calvyn T. Howells,
• Upendra K. Pandey,
• Joseph Cameron,
• Neil J. Findlay,
• Anto Regis Inigo,
• Tell Tuttle,
• Peter J. Skabara and
• Ifor D. W. Samuel

Beilstein J. Org. Chem. 2014, 10, 2683–2695, doi:10.3762/bjoc.10.283

• ; S, 10.72; found: C, 67.33; H, 7.60; N, 4.87; S, 11.00; MP: 109–111 °C. Device fabrication Indium tin oxide (ITO) coated glass substrates from Xin Yan Technology Ltd. (15 Ω /□) were masked and etched in hydrochloric acid (37%) for 20 minutes in order to get 4 mm wide strips. The substrates were then

Synthesis of graft polyrotaxane by simultaneous capping of backbone and grafting from rings of pseudo-polyrotaxane

• Kazuaki Kato,
• Katsunari Inoue,
• Masabumi Kudo and
• Kohzo Ito

Beilstein J. Org. Chem. 2014, 10, 2573–2579, doi:10.3762/bjoc.10.269

• a base [18]. Notably, the direct grafting from polyrotaxane with tin catalysts rather than DBU yielded a cross-linked GPR as a gel-like insoluble solid, indicating the necessity of the dissociation of the columnar crystal. Accordingly, GPR is not obtained if the polymerization from the ends of the

The effect of permodified cyclodextrins encapsulation on the photophysical properties of a polyfluorene with randomly distributed electron-donor and rotaxane electron-acceptor units

• Aurica Farcas,
• Ana-Maria Resmerita,
• Pierre-Henri Aubert,
• Flavian Farcas,
• Iuliana Stoica and
• Anton Airinei

Beilstein J. Org. Chem. 2014, 10, 2145–2156, doi:10.3762/bjoc.10.222

• , IP and EA compared to any of the constituents, which is necessary for electronic applications. The diagram with HOMO/LUMO levels and the work function of the indium tin oxide (ITO) coated glass substrates with poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) (anode) and Ca or Al

• compounds in addition to the work function of the indium tin oxide (ITO) coated glass substrates with poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) (anode) and Ca or Al (cathode) are available. Supporting Information File 554: Characterization data of the compounds: FTIR, 1H NMR

Influence of cyclodextrin on the UCST- and LCST-behavior of poly(2-methacrylamido-caprolactam)-co-(N,N-dimethylacrylamide)

• Alexander Burkhart and
• Helmut Ritter

Beilstein J. Org. Chem. 2014, 10, 1951–1958, doi:10.3762/bjoc.10.203

• measured at room temperature. FTIR spectra were recorded on a Nicolet 6700 FTIR spectrometer equipped with an ATR unit. Differential scanning calorimetry (DSC) was performed using a Mettler Toledo DSC 822 instrument equipped with a sample robot TSO801RO. For calibration, standard tin, indium, and zinc

Synthesis of rigid p-terphenyl-linked carbohydrate mimetics

• Maja Kandziora and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2014, 10, 1749–1758, doi:10.3762/bjoc.10.182

• -substituted 1,2-oxazines to bicyclic ketones has been described in many examples [24]. Gratifyingly, starting from 1,2-oxazine 4 with tin(IV) chloride as Lewis acidic promoter the corresponding ketone was obtained in excellent stereoselectivity. The subsequent protection of the primary hydroxy group as TBS

Efficient routes toward the synthesis of the D-rhamno-trisaccharide related to the A-band polysaccharide of Pseudomonas aeruginosa

• Aritra Chaudhury,
• Sajal K. Maity and
• Rina Ghosh

Beilstein J. Org. Chem. 2014, 10, 1488–1494, doi:10.3762/bjoc.10.153

• thioglycosides directly. Moreover, the use of stoichiometric amounts of the toxic tin hydride for radical-based reductive dehalogenation as required by the above method appeared undesirable especially in the preparative stages where reactions have to be set up on a large scale. On the other hand, Kiefel’s method

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

• ) metallacycle 6 (via tin(IV) precursors) active at low catalyst loadings (1–3%) in acetonitrile at 60 °C under a nitrogen atmosphere. The catalyst was effective with aromatic and aliphatic aldehydes, cyclic secondary amines, and phenyl- or TMS-acetylene providing the corresponding propargylamines 1 in excellent

One-pot synthesis of cyanohydrin derivatives from alkyl bromides via incorporation of two one-carbon components by consecutive radical/ionic reactions

• Shuhei Sumino,
• Akira Fusano,
• Hiroyuki Okai,
• Takahide Fukuyama and
• Ilhyong Ryu

Beilstein J. Org. Chem. 2014, 10, 150–154, doi:10.3762/bjoc.10.12

• reaction conditions where a catalytic amount of fluorous tin hydride and an excess amount of sodium cyanoborohydride were used, initially formed aldehydes can be converted into hydroxymethylated compounds in one-pot [7][8][9], since borohydride acts not only as the reagent for the regeneration of tin

N,N'-(Hexane-1,6-diyl)bis(4-methyl-N-(oxiran-2-ylmethyl)benzenesulfonamide): Synthesis via cyclodextrin mediated N-alkylation in aqueous solution and further Prilezhaev epoxidation

• Julian Fischer,
• Simon Millan and
• Helmut Ritter

Beilstein J. Org. Chem. 2013, 9, 2834–2840, doi:10.3762/bjoc.9.318

• calibration, standard tin, indium, and zinc samples were used. Heating and cooling curves were determined between −30 and 130 °C at a heating rate of 15 °C/min. The Tg value was taken from the inflection point of the second heating curve. Electrospray ionization mass spectrometry (ESIMS) was conducted on a

Oligomeric epoxide–amine adducts based on 2-amino-N-isopropylacetamide and α-amino-ε-caprolactam: Solubility in presence of cyclodextrin and curing properties

• Julian Fischer and
• Helmut Ritter

Beilstein J. Org. Chem. 2013, 9, 2803–2811, doi:10.3762/bjoc.9.315

• first three intersections of G’ and G’’ taking initial fluctuations due to homogenization and sheer-thinning processes not into account. Glass transition temperatures (Tg) were determined using a Mettler Toledo DSC 822e equipped with a sample robot TSO801RO. For calibration, standard tin, indium, and

Garner’s aldehyde as a versatile intermediate in the synthesis of enantiopure natural products

• Mikko Passiniemi and
• Ari M.P. Koskinen

Beilstein J. Org. Chem. 2013, 9, 2641–2659, doi:10.3762/bjoc.9.300

• temperature to rt the selectivity dropped further down to 3:2 (anti/syn). With chelating metals, such as Mg, Zn and Sn, the stereofacial preference changed from the re to the si side attack. The use of tin(IV) chloride as the chelating agent gave the highest syn-selectivities (>1:20 anti:syn), but poor yields

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

• the key aryl–aryl bonds and is suitable for analogue synthesis the route is not considered feasible for large scale synthesis due to the toxicity of the tin species and the inherent costs of the specifically functionalised starting materials and palladium catalysts. For this reason a de novo synthesis

• 1.119, which is first alkylated with epichlorohydrin (1.20) [63] (Scheme 22). The resulting epoxide 1.121 can then be ring opened with methanol in the presence of a tin Lewis acid yielding alcohol 1.122, which when subjected to Jones-oxidation conditions and Raney-Ni-mediated hydrogenation furnishes in

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

• Peter A. Wade Alma Pipic Matthias Zeller Panagiota Tsetsakos Department of Chemistry, Drexel University, Philadelphia, PA 19104, U.S.A Department of Chemistry, Youngstown State University, Youngstown, OH, U.S.A 10.3762/bjoc.9.251 Abstract The tin(IV)-catalyzed reaction of β-nitrostyrene with (E

• formal cycloadducts of (Z)-3-methyl-1,3-pentadiene. A Friedel–Crafts alkylation product from the reaction of the diene, β-nitrostyrene, and toluene was also obtained in 10% yield. The tin(IV)-catalyzed reaction of β-nitrostyrene with (Z)-3-methyl-1,3-pentadiene in dichloromethane afforded four nitronic

• intermediate. The initially isolated nitronic ester cycloadducts underwent tin(IV)-catalyzed interconversion, presumably via zwitterion intermediates. Cycloadducts derived from the reaction at the less substituted double bond of (E)-3-methyl-1,3-pentadiene underwent a [3,3]-sigmatropic rearrangement on heating

The chemistry of isoindole natural products

• Klaus Speck and
• Thomas Magauer

Beilstein J. Org. Chem. 2013, 9, 2048–2078, doi:10.3762/bjoc.9.243

• using an intramolecular Diels–Alder reaction. The synthetic endeavor began with the conversion of dihydropyran 79 to the acetal 80 (Scheme 9). Activation of the anomeric position with tin(IV) chloride presumably led to the formation of the oxonium ion 81. This intermediate was envisioned to undergo a

• oxalyl chloride and the Lewis acid tin(IV) chloride, a tandem cyclization (Bischler–Napieralski/Friedel–Crafts acylation reaction) was triggered to directly give 137 and 149 [122][127]. In 2006, another approach to aristoyagonine (136) was reported by the group of Couture (Scheme 20) [128]. For the

Flow Giese reaction using cyanoborohydride as a radical mediator

• Takahide Fukuyama,
• Takuji Kawamoto,
• Mikako Kobayashi and
• Ilhyong Ryu

Beilstein J. Org. Chem. 2013, 9, 1791–1796, doi:10.3762/bjoc.9.208

• Takahide Fukuyama Takuji Kawamoto Mikako Kobayashi Ilhyong Ryu Department of Chemistry, Graduate School of Science, Osaka Prefecture University, Sakai, Osaka 599-8531, Japan 10.3762/bjoc.9.208 Abstract Tin-free Giese reactions, employing primary, secondary, and tertiary alkyl iodides as radical

• 70 °C in combination with a residence time of 10–15 minutes gave good yields of the desired addition products. Keywords: continuous flow system; cyanoborohydride; flow chemistry; iodoalkanes; microreactor; tin-free Giese reaction; Introduction Organo halides are among the most useful precursors to

• C–C bond forming reactions or radical reduction as efficient substitutes for tin hydride reagents, whose toxicity is of great concern to organic chemists. Thus far we have demonstrated the borohydride-based tin-free Giese reactions [10] and the related radical carbonylation and hydroxymethylation

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

• boron enolate-based strategy using the N-acetylthiazolidinethione 58 (Scheme 14) for its high reported diastereoselectivity with aliphatic aldehydes and its avoidance of toxic tin reagents [61]. The reaction of the brightly colored 58 with but-3-enal proceeded in moderate yield, with an initial

Controlled synthesis of poly(3-hexylthiophene) in continuous flow

• Helga Seyler,
• Jegadesan Subbiah,
• David J. Jones,
• Andrew B. Holmes and
• Wallace W. H. Wong

Beilstein J. Org. Chem. 2013, 9, 1492–1500, doi:10.3762/bjoc.9.170

• following device geometry: ITO/PEDOT:PSS/P3HT:PC61BM (1:1)/ZnO nanoparticle/Al, where ITO = indium tin oxide, PEDOT:PSS = poly(3,4-ethylenedioxy-thiophene):poly(styrenesulfonate) and PC61BM = [6,6]-phenyl-C61-butyric acid methyl ester (Figure 5a). The P3HT:PC61BM active layer was deposited by spin coating

Cascade radical reaction of substrates with a carbon–carbon triple bond as a radical acceptor

• Hideto Miyabe,
• Ryuta Asada and
• Yoshiji Takemoto

Beilstein J. Org. Chem. 2013, 9, 1148–1155, doi:10.3762/bjoc.9.128

• moiety as an electron-deficient acceptor in the absence of a chiral ligand (Scheme 2). To control the rotamer population of substrates, Zn(OTf)2 was used as a Lewis acid to coordinate the hydroxamate ester functionality. The reactions were evaluated in CH2Cl2 at 20 °C under the tin-free iodine atom

C–C Bond formation catalyzed by natural gelatin and collagen proteins

• Dennis Kühbeck,
• Basab Bijayi Dhar,
• Eva-Maria Schön,
• Carlos Cativiela,
• Vicente Gotor-Fernández and
• David Díaz Díaz

Beilstein J. Org. Chem. 2013, 9, 1111–1118, doi:10.3762/bjoc.9.123

• tin plate and shielded by Pt (40 mA during 30 s for FE-SEM; film thickness ≈5 nm). Typical procedure for gelatin-catalyzed Henry reaction Nitromethane (27 μL, 0.5 mmol) was added in one portion to a 4 mL screw cap vial containing 4-nitrobenzaldehyde (15.1 mg, 0.1 mmol), PSTA gelatin (2 mg) and DMSO

Amyloid-β probes: Review of structure–activity and brain-kinetics relationships

• Todd J. Eckroat,
• Abdelrahman S. Mayhoub and
• Sylvie Garneau-Tsodikova

Beilstein J. Org. Chem. 2013, 9, 1012–1044, doi:10.3762/bjoc.9.116

• imidazopyridine, [18F]FPPIP (142), was prepared starting from 140e. A palladium-catalyzed coupling with tributyl(vinyl)tin to give an alkene intermediate was followed by hydroboration-oxidation to give the hydroxypropyl intermediate 145, which was radiolabeled to give 142 (Scheme 10B). This compound showed good

Direct alkenylation of indolin-2-ones by 6-aryl-4-methylthio-2H-pyran-2-one-3-carbonitriles: a novel approach

• Sandeep Kumar,
• Ramendra Pratap,
• Abhinav Kumar,
• Brijesh Kumar,
• Vishnu K. Tandon and
• Vishnu Ji Ram

Beilstein J. Org. Chem. 2013, 9, 809–817, doi:10.3762/bjoc.9.92

• ][28][29][30][31]. More recently, Kamijo, Yamamoto and co-workers [32] have developed a palladium-catalyzed cyclization of acetylenic aryl isocyanates in the presence of terminal alkynes. Halogenated arylpropionamides are commonly employed for the preparation of 3-alkenylindolin-2-ones involving tin

Some aspects of radical chemistry in the assembly of complex molecular architectures

• Béatrice Quiclet-Sire and
• Samir Z. Zard

Beilstein J. Org. Chem. 2013, 9, 557–576, doi:10.3762/bjoc.9.61

• [19]. Another solution is the tin-free degenerative radical transfer of xanthates and related derivatives we discovered a quarter of a century ago [20]. The simplified mechanism for the addition to an alkene is depicted in Scheme 6. The many subtle aspects embodied in the mechanism will not be