10.25560/1247
Qu, Tao
Imperial College London
Chemistry
Studies towards the synthesis of nano-diamondoid hydrocarbon cyclohexamantane
Imperial College London
2008
Barrett, Anthony GM
2008-04-08
2008-04-08
Doctor of Philosophy (PhD)
10044/1/1247
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.