Ladderane

A ladderane is an organic molecule containing two or more fused rings of cyclobutane. The name is a portmanteau because the serial cyclobutane rings look like a ladder and are singly bonded like alkanes. Ladderanes, like other cyclic rings, can be formed by the reduction of a carbon-carbon double bond into a single bond, concomitant with the creation of a new carbon-carbon bond to close the ring.

The geometry of ladderanes is highly strained because ligands to the carbon atoms cannot extend to their ideal angles. However, examples of ladderanes have been found in living organisms.