Filtern
Volltext vorhanden
- nein (86)
Erscheinungsjahr
Dokumenttyp
- Wissenschaftlicher Artikel (86) (entfernen)
Sprache
- Englisch (80)
- Deutsch (5)
- Chinesisch (1)
Gehört zur Bibliographie
- ja (86)
Schlagworte
- singlet oxygen (11)
- Synthetic methods (6)
- anthracenes (5)
- peroxides (4)
- Arenes (3)
- Birch reduction (3)
- Hydrogenation (3)
- Lactams (3)
- carbohydrates (3)
- photooxygenation (3)
- radicals (3)
- Carbohydrates (2)
- Conformational analysis (2)
- DFT calculations (2)
- Dynamic NMR (2)
- Lactones (2)
- arenes (2)
- auxiliary control (2)
- configuration (2)
- conformation (2)
- crystal structure (2)
- endoperoxides (2)
- naphthalenes (2)
- regioselectivity (2)
- stereoselectivity (2)
- synthesis (2)
- 2-Azaspiro[4.5]deca-1-ones (1)
- 4-Substituted cyclohexanones (1)
- 4-methylene-cyclohexyl pivalate (1)
- A-values of COOAr on cyclohexane (1)
- ALTONA equation (1)
- Absorption (1)
- Alkylation (1)
- Anomerization (1)
- Anthracene (1)
- Aromatic compounds (1)
- Benzoic acid esters (1)
- Cis- and trans-form (1)
- Configuration (1)
- Conformation (1)
- DNA (1)
- Diastereoselectivity (1)
- EPR spectroscopy (1)
- Fluorescence (1)
- Glycosidation (1)
- Glycosides (1)
- Gold (1)
- Hydrocarbons (1)
- Leishmania (1)
- Molecular diversity (1)
- Quantum chemical calculations (1)
- Reaction mechanisms (1)
- Reduction (1)
- Regioselectivity (1)
- Simulation of H-1 NMR spectra (1)
- [4+2] cycloaddition (1)
- beta-(acyloxy)alkylrear (1)
- carbohydrate derivatives (1)
- carbohydrate derivatives (1)
- carbohydrate recognition (1)
- chemistry (1)
- citrate displacement (1)
- conformational analysis (1)
- convenient synthesis (1)
- ct-DNA (1)
- cycloaddition (1)
- cyclopropanation (1)
- density functional calculations (1)
- docking (1)
- donor-acceptor systems (1)
- dynamic NMR spectroscopy (1)
- enzyme catalysis (1)
- enzyme inhibitors (1)
- exo-methylene conformational effect at cyclohexane (1)
- fluorescence enhancement (1)
- glycal (1)
- glycals (1)
- gold nanoparticles (1)
- groove binding (1)
- heteroatoms (1)
- interactions (1)
- intercalations (1)
- intermediates (1)
- kinetics (1)
- labile peroxides (1)
- lithography (1)
- low-temperature experiments (1)
- mechanism (1)
- mild reaction conditions (1)
- mitochondria (1)
- naphthalene (1)
- one-pot reaction (1)
- oxidation (1)
- oxygenation (1)
- photochemistry (1)
- photochromism (1)
- photodynamic therapy (1)
- plasmon spectroscopy (1)
- quantum chemical calculations (1)
- radical addition (1)
- rangement (1)
- reaction mechanism (1)
- reaction mechanisms (1)
- reactive (1)
- reactive intermediates (1)
- rearrangement (1)
- reversibility (1)
- sandwich complexes (1)
- selective oxidations (1)
- selective syntheses (1)
- solvent effect (1)
- stereoselective-synthesis (1)
- steric hindrance (1)
- substituent effects (1)
- sugar amino acids (1)
- sugars (1)
- thin films (1)
- thiols (1)
Institut
- Institut für Chemie (86) (entfernen)
Two different approaches. with an unsaturated carbohydrate as a radical acceptor and a carbohydrate derived aldehyde as a radical precursor, led to key intermediates in the synthesis of 3-deoxy-D-oct-2-ulosonic acids (KDO). Manganese(III) acetate and cerium(IV) ammonium nitrate were the reagents of choice for the oxidative generation of radicals, whereas samarium(II) iodide was employed for reductive couplings. Both strategies were realized by using easily available starting materials, with acetic acid as C-2 and ethyl acrylate as C-3 building blocks, respectively
The title compounds, [(1R,3R,4R,5R,6S)-4,5-bis(acetyloxy)-7-oxo-2-oxabicyclo-
[4.2.0]octan-3-yl]methyl acetate, C14H18O8, (I), [(1S,4R,5S,6R)-5-acetyloxy-7-
hydroxyimino-2-oxobicyclo[4.2.0]octan-4-yl acetate, C11H15NO6, (II), and
[(3aR,5R,6R,7R,7aS)-6,7-bis(acetyloxy)-2-oxooctahydropyrano[3,2-b]pyrrol-5-
yl]methyl acetate, C14H19NO8, (III), are stable bicyclic carbohydrate derivatives.
They can easily be synthesized in a few steps from commercially available
glycals. As a result of the ring strain from the four-membered rings in (I) and
(II), the conformations of the carbohydrates deviate strongly from the ideal
chair form. Compound (II) occurs in the boat form. In the five-membered
lactam (III), on the other hand, the carbohydrate adopts an almost ideal chair
conformation. As a result of the distortion of the sugar rings, the configurations
of the three bicyclic carbohydrate derivatives could not be determined from
their NMR coupling constants. From our three crystal structure determinations,
we were able to establish for the first time the absolute configurations of all new
stereocenters of the carbohydrate rings.
Catalytic amounts of a weak base are sufficient to induce the decomposition of anthracene endoperoxides to anthraquinone. The mechanism has been elucidated by isolation of intermediates in combination with DFT calculations. The whole process is suitable for the convenient generation of hydrogen peroxide under very mild conditions.