ORGN 384 |
| Much recent attention has been paid to the development of synthetic molecular receptors with the ability to recognise selectively small molecules involved in biological pathways. Fluorescent sensors are preferred because they are well suited to meet the need for in vivo probes, such as mapping the spatial and temporal distribution of the biological analytes. Boronic acid molecular receptors for saccharides have attracted considerable interest due to the ability to bind saccharides via covalent interactions in aqueous media. The most common interaction of the boronic acids is with the cis-1,2- or 1,3-diols of saccharides to form five- or six-member rings. Many naturally occurring molecules, including saccharides, involved in critical biological process are chiral compounds. Obviously, a chiral receptor will be inheranty more selective for chiral guests than achiral receptors, since the resulting complexes are diastereomeric. Chiral sensors can be enantioselective but, differences in the stability of diasteriomeric complexes can also result in ehnanced chemoselectivity. This presentation will cover the recent results obtained in our group for two different chiral receptors. The first system employs the rigid axial chirality of BINOL in the construction of sensor 1 (with BINOL functioning as both the chirogenic center and fluorophore). Unfortunately, in this case, the chiral center was not in close proximity to the receptors binding site, and BINOL has poor fluorescence properties.[Angew. Chem. Int. Ed., 2004, 43, 3461] Therefore, we designed fluorescent chiral sensors 2 and 3 which have two chiral centers in close proximity to the binding site of the receptor and used anthracene, a good fluorophore.[J. Am. Chem. Soc, 2004, 126, 16179; Chem. Commun, 2005, 1560-1562] In particular the properties of these sensors for sugar acids (α-hydroxy acids) such as tartaric acid and sugar alcohols such as mannitol will be discussed.
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Molecular Recognition and Self-Assembly
8:00 AM-12:00 PM, Tuesday, 12 September 2006 Moscone Center -- Room 132, Oral
Division of Organic Chemistry |
