A naturally occurring -ladderane lipid, named pentacycloanammoxic acid, has been synthesized by Corey and coworkers. The first step in this reaction involves bromination followed by cyclization of cyclooctatetraene to form a cyclohexadiene. This cyclohexadiene is trapped by dibenzyl azodicarboxylate. Functional group modifications are made to produce a cyclobutane which is elaborated through a with a cyclopentenone to produce a second cyclobutane ring. Protection of the carbonyl group, followed by a N2 extrusion reaction, yields two more fused cyclobutane rings. The final cyclobutane is formed by a Wolff rearrangement, and the alkyl chain is installed by a Wittig olefination.