Abstract
(±)-Raikovenal (1a) has been synthesized in five steps from dihydrofilifolone (3) by two Wittig reactions. A similar sequence provides (±)-preraikovenal from aldehyde 11. Epiraikovenal (1b) has been prepared by photolysis of preraikovenal or by photolysis of 5 to give 4b. Lewis acid induced cyclization of enal 5 gives cyclopentylideneacetaldehyde 16 rather than bicyclo[3.2.0]heptanecarboxaldehyde 4.