| Autor: |
Crich D; Department of Chemistry, University of Illinois at Chicago, 845 West Taylor Street, Chicago, Illinois 60607-7061, USA. dcrich@uic.edu, Shirai M, Rumthao S |
| Jazyk: |
angličtina |
| Zdroj: |
Organic letters [Org Lett] 2003 Oct 02; Vol. 5 (20), pp. 3767-9. |
| DOI: |
10.1021/ol035564x |
| Abstrakt: |
[reaction: see text] Enantiomerically enriched beta-(diphenylphosphatoxy)nitroalkanes undergo radical ionic fragmentation, induced by tributyltin hydride and AIBN in benzene at reflux, to give alkene radical cations in contact radical ion pairs. These contact ion pairs are trapped intramolecularly by amines to give pyrrolidines and piperidines with significant enantioselectivity ( approximately 60% ee), indicative of cyclization competing effectively with equilibration within the ion pairs. Use of an intramolecular N-propargylamine as a nucleophile provides an enantiomerically enriched pyrrolizidine skeleton via a tandem polar/radical crossover sequence. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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