Abstract
The evolution of a convergent strategy that led to efficient, enantioselective syntheses of both natural (+)- and unnatural (-)-guanacastepene E and formal total syntheses of (+)- and (-)-guanacastepene A is described. A union of five- and six-membered ring intermediates by an efficient π-allyl Stille cross-coupling reaction was followed by an intramolecular enone-olefin [2 + 2] photocycloaddition and a stereoelectronically controlled, reductive fragmentation of the resulting cyclobutyl ketone. The latter two transformations enabled controlled formation of the C-11 quaternary stereocenter and the central seven-membered ring of the guanacastepenes. An enantiospecific synthesis of the functionalized five-membered ring vinyl stannane from the monoterpene R-(-)-carvone featuring a carbon-carbon bond forming ring contraction was also developed.
Original language | English (US) |
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Pages (from-to) | 7025-7035 |
Number of pages | 11 |
Journal | Journal of the American Chemical Society |
Volume | 128 |
Issue number | 21 |
DOIs | |
State | Published - May 31 2006 |
All Science Journal Classification (ASJC) codes
- General Chemistry
- Biochemistry
- Catalysis
- Colloid and Surface Chemistry