Intramolecular 4 + 3 cycloadditions. Aspects of stereocontrol in the synthesis of cyclooctanoids. A synthesis of (+)-dactylol.

[reaction: see text] The judicious placement of stereocenters on precursors for 4 + 3 cycloaddition reactions can lead to high levels of stereocontrol in the 4 + 3 cycloaddition process of cyclopentenyl cations and tethered butadienes. This concept was successfully tested in the context of a synthesis of (+)-dactylol.