ORGN 219 |
| A coupling protocol has been developed that allows a yield- and time-efficient synthesis of oligo(p-benzamide) foldamers on solid support. During synthesis, prevention of hydrogen bond formation among the aromatic amides was achieved using N-p-methoxy benzyl (PMB) protection. The absence of hydrogen bond donors in the N-protected amides as well as the preferential cis-conformation of aromatic amides greatly enhances solubility of the growing oligomers. The solubilising cis-conformation of the N-substituted oligo(p-benzamide)s was ascertained by conformational investigations in solution as well as in the solid state. By converting the aromatic carboxylic acids into acid chlorides under otherwise mild conditions, a reliable activation method has been investigated allowing the acylation of secondary aromatic amines on solid support. After cleavage of the N-protected oligo(p-benzamide)s from the resin, the temporary PMB-protection was easily removed using trifluoroacetic acid. Oligo(p-benzamide)s are important building blocks for supramolecular chemistry as they allow highly directional non-covalent interactions with tuneable aggregation strength depending on oligomer length. The solid supported synthesis of such shape persistent nanoscale molecular objects provides a combinatorial way for the development of new supramolecular structures.
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Asymmetric Reactions and Syntheses, Metal-Mediated Reactions, Combinatorial, Parallel, and Solid-Phase Chemistry
8:00 PM-10:00 PM, Sunday, 10 September 2006 Moscone Center -- Hall D, Poster
Sci-Mix
Division of Organic Chemistry |
