کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1314833 | 975988 | 2008 | 8 صفحه PDF | دانلود رایگان |
We describe in full-detail the synthesis of new ψ[CH(RF)NH]-peptidomimetics, having different fluoroalkyl groups RF, as peptide bond surrogates. A key step in the synthesis is a stereoselective aza-Michael addition of chiral α-amino acid esters to β-fluoroalkyl-α-nitroethenes. The diastereoselection of the process was influenced by the electronegativity, rather than by the steric bulk, of the fluorinated residue RF in the β-position of the nitroalkene acceptors. Replacement of a single F atom of RF by a hydrogen or methyl group brings about a dramatic drop of stereocontrol, whereas Br, Cl and CF3, albeit bulkier than F, provide inferior results in terms of stereocontrol. A mechanistic hypothesis is provided.
We describe in full-detail the synthesis of new ψ[CH(RF)NH]-peptidomimetics, having different fluoroalkyl groups RF, as peptide bond surrogates. A key step in the synthesis is a stereoselective aza-Michael addition of chiral α-amino acid esters to β-fluoroalkyl-α-nitroethenes. The diastereoselection of the process was influenced by the electronegativity, rather than by the steric bulk, of the fluorinated residue RF in the β-position of the nitroalkene acceptors. Replacement of a single F atom of RF by a hydrogen or methyl group brings about a dramatic drop of stereocontrol, whereas Br, Cl and CF3, albeit bulkier than F, provide inferior results in terms of stereocontrol. A mechanistic hypothesis is provided.Figure optionsDownload as PowerPoint slide
Journal: Journal of Fluorine Chemistry - Volume 129, Issue 9, September 2008, Pages 767–774