| Research Abstract |
During the course of our synthetic study of nonhydrolyzabk phosphoamino acid mimetics, we found that γ,γ-difluoro-α,β-enoates were reduced to the corresponding γ-fluoro-β,γ-enoates by organocopper reagents. This reduction was successfully applied to the synthesis of fluoroalkene dipeptide isosteres. During the term of the project, we found several finding as shown below
1. Organocoppermediated reduction seems to proceed via single electron transfer mechanism
2. Based on the above mechanism, reductionoxidative alkylation procedure for the synthesis of α-substituted fluoroalkene dipeptide isosteres
3. SmI_2, representative one-electron reducing agent, is also applicable to the synthesis of fluoroalkene dipeptide isosteres
4. In the SmI_2mediated reduction of γ,γ-difluoro-α,β-enoates, Sm(III)dienolate spicies are likely to be involved Based on formation of this plausible intermediate, kinetitic trapping of the intermediate by aldehydes or ketones were attempted. And this kinetic trapping procedure is proved to be useful for the synthesis of α-substituted fluoroalkene dipeptide isosteres
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