Recently, we reported a new strategy to synthesize linearly fused triquinanes from alkylidene carbenes via trimethylenemethane(TMM) diyl intermediates. We were able to extend this novel methodology to the synthesis of angularly fused triquinanes. The intramolecular [2+3] cycloaddition reaction of the trimethylenemethane(TMM) diyl generated from the intramolecular cyclopropanation reaction of alkylidene carbene produced angularly fused triquinanes regio- and stereoselectively.
We were also interested in various ways of generating trimethylenemethane(TMM) diyl intermediates for the construction of angularly fused triquinanes. The scope and the application of this methodology to the total synthesis of dl-pentalenene will be presented.