ORGN 558 |
| Pyrrolidines are an important structural motif found in a large number of natural products and the ability to construct them in an enantiopure fashion remains a significant challenge for organic chemists. Two separate approaches towards this target are reported here, both of which rely upon the ammonia-free partial Birch reduction using lithium and di-tert-butylbiphenyl as a source of electrons. The first explores the use of oxazolidinones for the chiral protonation of enolates formed during partial reduction in the ammonia-free Birch reaction. This results in the formation of mono-substituted N-Boc pyrrolines in moderate to good enantiomeric excess. In the second method an enzymatic approach is used to desymmetrise pyrrolines - formed from the Birch reduction of both mono-and disubstituted N-Boc pyrroles - in good yields and with excellent enantiopurity.
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New Reactions and Methodology, Heterocycles and Aromatics, Bioorganic Chemistry
8:00 PM-10:00 PM, Tuesday, 12 September 2006 Moscone Center -- Hall D, Poster
Division of Organic Chemistry |
