From the retrosynthetic perspective, tricyclic ketone 3 appeared to be an ideal advanced synthetic intermediate in that the cyclobutene ring could serve as a latent furan. That is, oxidative cleavage of the olefinic linkage followed by dehydration would afford the requisite furan (2). Subsequent introduction of a carbonyl group at C (7) and an axial methyl at C (6) would then complete the synthesis. Such a scenario, of course, depends critically on the ...
