Preparation and Rearrangement of 1,2-Dialkenylcyclobutanols. A Useful Method for Synthesis of Substituted Cyclooctenones

Article abstract of DOI:10.1021/jo00133a007

The syntheses and anionic oxy-Cope rearrangements of 1,2-dialkenylcyclobutanols are reported.Reaction of 2-methyl-2-(2-methylpropen-1-yl)-1-cyclobutanone (1) with vinyl-, isopropenyl-, or isobutenyllithium led to formation of cyclobutanols 2a-c.Treatment with potassium hydride induced rearrangement to Z and E cyclooctenones 3a-c and 4a,c.Reaction of 5-methylenespiro<3.5>nonan-1-one (8) with the same alkenyllithium reagents afforded directly a mixture of rearranged and ring-opened products (11a-c and 12a-c).Reaction of spiro<3.5>non-5-en-1-one (17) with vinyl- or isopropenylmagnesium bromide produced a mixture of diastereomeric cyclobutanols 18a,b and 19a,b which underwent anionic oxy-Cope rearrangement to bicyclo<5.3.1>undec-1(11)-en-4-ones 20a,b in high yield.A mechanism for the rearrangement of stereodistal 1,2-dialkenylcyclobutanols is proposed.