Towards a Total Synthesis of C60

Abstract

Following an introduction to the history, chemistry and synthetic approaches to buckminsterfullerene [C60, (1)], the C15H18 hydrocarbon “trindane” (63) is introduced as the starting point for a variety of proposed strategies for C60's synthesis. Investigations are made into the direct synthesis of polycyclic aromatic hydrocarbons from cyclopentene and trindane (both repeating units within the structure of C60). The elevated-temperature and high-pressure conditions used (in the presence of dehydrogenating catalysts and aromatising agents) were insufficient at promoting the extensive dehydrogenative coupling of cyclopentene and trindane desired. The remainder of the thesis is concerned with two proposed formal synthetic routes to C60, both heavily symmetry dependent and based on the use of trindane. One relies on Diels-Alder coupling of the two C30 compounds (75) and (76) [derived from either of the readily prepared "trindanone" dimers (73) and (74)] to give the T-shaped molecule (77), which on dehydration and dehydrogenation could afford the spherical target by a "tennis ball" approach (Scheme 26, p.47). The other is based on the C45 bowl-like trindane trimer (89) (p. 51), which could be capped by a trindane lid to afford (94) prior to dehydrogenation (Scheme 32, p. 51). Progress along these routes is reported and two relevant but "off-route" C45 compounds (242) and, (261) are described, their structures being determined by X-ray crystallographic methods. A paper published in J. Chem. Soc., Perkin Trans. 1, which summarises much of the synthetic work discussed in the current study, has been included as Appendix IV (p. 207). A fold-out sheet showing the structures of the most commonly referred to compounds is included at the end of this thesis (p. 233).