| Autor: |
Beck, H., Stark, C. B. W., Hoffmann, H. M. R. |
| Zdroj: |
Organic Letters; April 2000, Vol. 2 Issue: 7 p883-886, 4p |
| Abstrakt: |
A series of enantiomerically pure 8-oxabicyclo[3.2.1]oct-6-en-3-ones functionalized in the unsaturated two-carbon bridge has been prepared by the title reaction. Carbocation reactivity has been fined-tuned at −95 °C and adjusted to diene nucleophilicity. Conventional electrophilic substitution of 3-silylated and 3-stannylated furan is suppressed in favor of the rapid 4 + 3 cycloaddition mode. In the case of cycloadduct 13A, stereoselectivity (17:1) is perfectly matched to regioselectivity (17:1). High stereoselection as well as unprecedented regioselection and chemoselection is attributed to the low-temperature cycloaddition protocol and the design of chiral auxiliary and tether. |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
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