ORGN 436 |
| Glycal azidoformates and glycal carbamates serve as nitrene and nitrenoid precursors, leading to C=C insertion and in situ glycosylation. We have used this strategy under either photochemical or metal-mediated conditions to prepare 2-amido allo- and manopyranosides. Anomeric stereoselectivity depends on C3 stereochemistry, solvent polarity, and choice of protecting groups. In reactions of glucal 3-carbamates leading to 2-mannosamine derivatives, a C3-oxidized dihydro-4-pyranone byproduct forms. Recent experiments have led to higher levels of anomeric stereocontrol, less byproduct, and an improved mechanistic understanding. We have also applied the methodology toward a synthesis of the disaccharide portion of the chitinase inhibitor allosamidin.
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ACS Award for Research at an Undergraduate Institution
8:00 AM-12:00 PM, Wednesday, 29 March 2006 Georgia World Congress Center -- C303/304/305, Oral
Division of Organic Chemistry |
