Abstract
(±)-Kelsoene (1 ) has been synthesized in 15 steps from commercially available cyclopent-2-en-1-one.
Key steps include (a) a methylenecyclopentane annulation of cyclopent-2-en-1-one using
the bifunctional cuprate reagent lithium cyano(4-chlorobut-1-en-2-yl)cuprate and (b)
a highly stereoselective [2+2]-photocycloaddition of ethylene to the bicyclic enone
10 .
Key words
kelsoene - annulation - bifunctional reagent - photocycloaddition - Wilkinson’s catalyst
- Lombardo’s reagent
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