共查询到20条相似文献,搜索用时 46 毫秒
1.
Tushar van der Wijst Célia Fonseca Guerra Dr. Marcel Swart Dr. F. Matthias Bickelhaupt Prof. Dr. Bernhard Lippert Prof. Dr. 《Angewandte Chemie (International ed. in English)》2009,48(18):3285-3287
Pass the salt, please! State‐of‐the‐art computations indicate that the stacking complex of a guanine quartet and an adenine quartet (G4A4) can function as a potent ditopic receptor for NaCl in aqueous solution (see picture; Na+, Cl? yellow, O red, N blue, C black, H white).
2.
Dorothea Richter Dipl.‐Chem. Herbert Mayr Prof. Dr. 《Angewandte Chemie (International ed. in English)》2009,48(11):1958-1961
How are dihydropyridines like indoles? Both groups of compounds have similar nucleophilicity parameters N and are therefore suitable substrates for iminium‐catalyzed reactions of α,β‐unsaturated aldehydes. The N parameters of 1,4‐dihydropyridines were derived from the rates of hydride transfer reactions to benzhydrylium ions (see scheme).
3.
Cecilia Anaya de Parrodi Prof. Patrick J. Walsh Prof. 《Angewandte Chemie (International ed. in English)》2009,48(26):4679-4682
Alkynes of reactions : Recent breakthroughs in metal‐catalyzed alkyne reactions, which expand the synthetic utility of alkynes, have been achieved. These approaches broaden the range of alkynes that are accessible by C? N and C? C bond‐forming reactions and demonstrate that the use of bifunctional heterobimetallic catalysts can lead to new reactivity and excellent enantioselectivity (see scheme).
4.
5.
6.
Atul Asati Santimukul Santra Dr. Charalambos Kaittanis Sudip Nath Dr. J. Manuel Perez Prof. 《Angewandte Chemie (International ed. in English)》2009,48(13):2308-2312
Inorganic enzyme? Ceria nanoparticles exhibit unique oxidase‐like activity at acidic pH values. These redox catalysts can be used in immunoassays (ELISA) when modified with targeting ligands (see picture; light blue and yellow structures are nanoparticles with attached ligands). This modification allows both for binding and for detection by the catalytic oxidation of sensitive colorimetric dyes (e.g. TMB).
7.
《Angewandte Chemie (International ed. in English)》2009,48(15):2635-2635
“My first experiment was preparation of proline‐derived chiral ligands for asymmetric alkylation. My favorite subjects at school were history and English…?.” This and more about Keisuke Suzuki can be found on page 2635.
8.
9.
Sebastian Bartsch Dipl.‐Biochem. Uwe T. Bornscheuer Prof. 《Angewandte Chemie (International ed. in English)》2009,48(18):3362-3365
All ways lead to Rome? Computer modeling and kinetic measurements identified a distinct residue in Phe/Tyr ammonia lyases (PAL/TAL) which controls whether the Friedel–Crafts or an E1cB reaction mechanism takes place. Hence, Glu484 in pcPAL favors the Friedel–Crafts reaction (see picture, MIO=4‐methylidene imidazol‐5‐one) whereas an Asn in TAL gives an elimination reaction. These mechanistic investigations also reveal activity of a PAL mutant and a TAL towards an amino alcohol.
10.
Zhuangzhi Shi Chun Zhang Si Li Delin Pan Shengtao Ding Yuxin Cui Dr. Ning Jiao Dr. 《Angewandte Chemie (International ed. in English)》2009,48(25):4572-4576
Pd doles it out : A palladium‐catalyzed approach to indoles using the title reaction was achieved (see scheme). The oxidant used in this catalytic cycle was O2. Both N‐nonsubstituted and N‐alkyl monosubstituted anilines can be successfully transformed into the corresponding indoles by this method.
11.
As simple as it gets! Potassium tert‐butoxide alone catalyzes the direct dehydrogenative Si? O coupling of several synthetically important silanes with 1°, 2°, and even 3° alcohols without the need for stoichiometric hydrochloric acid scavengers. The stereoretentive mechanism is probed with a silicon‐stereogenic silane.
12.
Benoît Join Dr. Takuya Yamamoto Kenichiro Itami Prof. Dr. 《Angewandte Chemie (International ed. in English)》2009,48(20):3644-3647
Efficient couplings using equimolar quantities of each coupling partner and multiple C? H bond arylation reactions are achieved with an Ir‐based catalytic system for the C? H bond arylation of electron‐rich heteroarenes with iodoarenes to construct extended π‐systems. The dramatic ligand effect on reaction efficiency leads to the discovery that Crabtree's catalyst (see scheme) is the optimal catalyst precursor.
13.
14.
Despina Tzoulaki Lars Heinke Hyuna Lim Jing Li Prof. Dr. David Olson Prof. Dr. Jürgen Caro Prof. Dr. Rajamani Krishna Prof. Dr. Christian Chmelik Dr. Jörg Kärger Prof. Dr. 《Angewandte Chemie (International ed. in English)》2009,48(19):3525-3528
Easy come, easy go? Transport resistances on particle surfaces are important for mass transfer in nanoporous materials and bulk diffusion in crystals. Interference microscopy and IR micro‐imaging are shown to be excellent tools for determining such transport resistances. By studying short‐chain‐length alkane guest molecules in crystals of the metal–organic framework compound Zn(tbip) a data collection of surface permeabilities is established.
15.
Yong Guo Dr. Xiaming Zhao Dr. Dazhi Zhang Dr. Shun‐Ichi Murahashi Prof. Dr. 《Angewandte Chemie (International ed. in English)》2009,48(11):2047-2049
Catalytic convenience : The use of iridium or ruthenium catalysts for C? H bond activation has led to the addition reaction of trifluoromethylated compounds to alkenes (see scheme). This atom‐economical reaction occurs under neutral reaction conditions and without the formation of undesired defluorinated by‐products, even at high temperature.
16.
Two in one : The simultaneous formation of bimetallic μ‐methylene bridged RhIII complexes as well as dimeric RhIII complexes with terminal chloromethyl groups is observed for P,N‐ligand stabilized RhI complexes by C? Cl bond activation of methylene chloride. A mechanistic proposal for the formation of both activation products is also discussed.
17.
18.
Hans‐Jrg Schneider 《Angewandte Chemie (International ed. in English)》2009,48(22):3924-3977
Forces to reckon with : Supramolecular complexes, such as the one shown, are normally based on a combination of different interactions such as ion pairing, hydrogen bonds, and stacking interactions. The not always simple characterization of the nature and strength of intermolecular forces provides assistance to the understanding of biomimetic systems, as well as for the design of synthetic receptors, drugs, and intelligent materials.
19.
Synergy in synthesis : Strategic consideration of metathesis and Suzuki–Miyaura (SM) cross‐coupling for C? C bond‐formation processes has opened up new and “green” synthetic routes to various complex targets. The use of this synergistic combination for the synthesis of supramolecular ligands, polyaromatic compounds, and complex natural products is covered in this Focus Review.
20.
Hayato Ishikawa Dr. Takaki Suzuki Yujiro Hayashi Prof. Dr. 《Angewandte Chemie (International ed. in English)》2009,48(7):1304-1307
Taking shortcuts : A remarkably short and high‐yielding asymmetric total synthesis of (?)‐oseltamivir takes advantage of organocatalysis and single‐pot domino operations. The target, known as the drug Tamiflu, is prepared efficiently in a short time, and also its derivatives can be synthesized effectively.