ORGN 555 |
| Tetrahydrofurans (THFs) are frequently found in several important synthetic intermediates and natural products. Recent work in the Armstrong group has developed a novel aminative rearrangement of alkoxydihydropyrans to pyrrolidines. In line with the pyrrolidine series, we investigated an equally rapid route to THFs by the epoxidation of alkoxydihydropyrans. We were particularly interested in whether substituents on the pyran substrate could control the relative configuration and the absolute configuration of the THF products. Firstly, the epoxidation of pyrans 1 with sterically demanding substituents using DMDO gave highly diastereoselective formation of 4,5-cis-THFs 2 (up to 95% dr). Furthermore, this method was applied to the synthesis of gamma-lactone-containing natural products. Secondly, the asymmetric epoxidation of aryl-substituted pyrans 3 using a Mn (salen) catalyst gave highly enantioselective formation of THFs 4 (up to 80% ee).
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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 |
