Macrocyclic module compositions are made from cyclic synthons. The macrocyclic module structures are prepared by stepwise or concerted schemes which couple synthons in a closed ring. The macrocyclic module structures may have a pore of nanometer dimensions.
Synthesis of both Enantiomers of Hemiesters by Enantioselective Methanolysis of Meso Cyclic Anhydrides Catalyzed by α-Amino Acid-Derived Chiral Thioureas
作者:Rubén Manzano、José M. Andrés、María-Dolores Muruzábal、Rafael Pedrosa
DOI:10.1021/jo100792r
日期:2010.8.6
ureas and thioureas derived from l- or d-valine act as bifunctionalorganocatalysts able to induce the enantioselectivealcoholysis of mono-, bi-, and tricyclic meso anhydrides. The desymmetrization occurs in near quantitative yields and excellent enantiomeric ratios (up to >99:<1) under low catalyst loading. Both enantiomers of the hemiesters can be directly obtained by changing the configuration of the
A Chiral Bifunctional Sulfonamide as an Organocatalyst: Alcoholysis of σ-Symmetric Cyclic Dicarboxylic Anhydrides
作者:Shigeki Sano、Takashi Honjo、Takeshi Tsumura、Yoshimitsu Nagao、Kentaro Yamaguchi、Yoshihisa Sei
DOI:10.1055/s-0029-1218374
日期:2009.12
Enantioselective alcoholysis of σ-symmetric cyclicdicarboxylicanhydrides with benzyl alcohol catalyzed by a chiralbifunctionalsulfonamide was achieved in up to 98% ee at 5 mol% loading.
Nanofilms useful for filtration are prepared from oriented amphiphilic molecules and oriented macrocyclic modules. The amphiphilic species may be oriented on an interface or surface. The nanofilm may be prepared by depositing or attaching an oriented layer to a substrate. A nanofilm may also be prepared by coupling the oriented macrocyclic modules to provide a membrane.
General Synthesis of Unsymmetrical Norbornane Scaffolds as Inducers for Hydrogen Bond Interactions in Peptides<sup>,</sup>
作者:Christian P. R. Hackenberger、Ingo Schiffers、Jan Runsink、Carsten Bolm
DOI:10.1021/jo030295+
日期:2004.2.1
Starting from readily accessible endo-cis-(2S,3R)-norbornene dicarboxylic acid benzyl monoester, a general and efficient synthetic approach toward unsymmetrical two-stranded peptidic structures was developed. In these structures the peptide strands are oriented in a parallel geometry. Their synthesis is easily applicable to a variety of amino acids and peptides. Specifically, a norbornane template as molecular scaffold induces hydrogen bonding between the adjacent peptide strands. The specific hydrogen bonding patterns between these strands were revealed by detailed NMR analysis including TOCSY/NOE experiments.