Barrelene is
hydrogenated with hydrogen gas and
Adams' catalyst in
ethanol to the fully saturated bicyclooctane|bicyclo[2.2.2]-octane.
Bromination with
bromine in
tetrachloromethane gives a di-bromo adduct because a
coupling reaction intervenes: :
Epoxidation of barrelene with
oxone gives the trioxatrishomobarrelene which on
rearrangement with
boron trifluoride (driving force:relief of
strain energy) converts into the trioxatrishomocubane: : This compound can be envisioned as a
cubane with three oxygen atoms inserted into three opposite edges or as
9-crown-3 capped by two
methine units. The molecule is
chiral and the separate
enantiomers have been isolated. Certain barrelenes have been used as a
monomer in a
ring opening metathesis polymerization: : The catalyst is a
Schrock carbene (a
molybdenum bis-(hexafluoro-tert-butoxy) carbene catalyst) and the long alkyl chain attached to the monomer is required for solubility. Oxidation of the polymer with
DDQ affords the naphthalene pendant of
poly(p-phenylene vinylene).
Isopentane solutions of barrelene undergo
photolytic isomerisation when
acetone is added as a
photosensitizer to produce
semibullvalene. Prolonged irradiation results in further isomerisation to form
cyclooctatetraene. : ==Notes==