Adamantane (C10H16) is the smallest unit cage structure of the diamond crystal lattice.
Other diamondoid hydrocarbons are also known, such as diamantane and triamantane.
In 2003, the isolation and structural elucidation of a highly symmetrical and remarkably
stable “natural product” cyclohexamantane (C26H30) was reported.1 The structure of the
nanometer-sized hydrocarbon cyclohexamantane was shown by X-ray crystallography
to be the largest fully characterized fragment of the diamond lattice. Higher order
diamondoid hydrocarbons may have great potential applications in pharmaceuticals,
microelectronics and nanotechnology.2
Prior to von Schleyer’s outstanding synthesis3, adamantane was a rare compound and
only available in small quantities. The success to von Schleyer’s synthesis was his
appreciation of the fact that adamantane is the most stable hydrocarbon of formula
C10H16. He used this knowledge to bring about the Lewis acid catalysed rearrangement
(via a sequence of Wagner-Meerwein shifts) of a strained hydrogenated
cyclopentadiene dimer (C10H16) to provide adamantane in high yield.
Our research goal is to prepare hydrocarbon precursors of formula C26H32 and to study
their dehydrogenative rearrangements under acidic conditions as a concise synthetic
route to cyclohexamantane (C26H30). Our investigations into two different approaches to
build the rearrangement precursors (C26H32) are described in this thesis. In the first
approach, a four-directional synthesis of the rearrangement precursor has been
examined through Route A and Route B. A more concise approach via the Diels-Alder dimerisation of adamantanocyclopentadiene is also described herein.