The shortest enantioselective total syntheses of (+)-isolaurepinnacin and (+)-neoisoprelaurefucin have been accomplished. These syntheses were based on a common parallel synthetic strategy using Prins-Peterson cyclization in their core construction. In only one step, a seven-membered ring oxacycle with the correct cis-stereochemistry ring closure and the Δ4 position of the endocyclic double bond in (+)-isolaurepinnacin was obtained. This unsaturation was also necessary to accede to the bromodioxabicycle on (+)-neoisoprelaurefucin.