Photochemical Approaches to the Synthesis of [n]Prismanes

Notwithstanding their structural regularity, many years of effort were needed before the first three members, prismane ([3]prismane)

,

cubane ([4]prismane)

,

and pentaprismane ([5]prismane)

,

could be successfully synthesized. Recently, attention has been focused on the challenging objective of constructing the higher prismanes, in particular, hexaprismane ([6]prismane)

. The molecules in the prismane family are highly strained due to their unusual structural features, extended CC bond lengths, and deformed bond angles. Their strain energies are estimated to be 140-178 kcal/mol based on

ab initio

MO calculations (6-31G*).