Proposed tennis ball and basket- and -lid routes to C60:: two relevant C45 compounds

Two formal synthetic routes to C-60, both heavily symmetry dependent and based on the use of the C15H18 hydrocarbon "trindane" (1) which is a repeating unit within the spherical structure, are proposed. One relies on Diels-Alder coupling of the two C-30 derivatives 5 and 6 of the readily prepared "trindanone" dimer 3 to give the T-shaped molecule 7 which on dehydration and dehydrogenation could afford the spherical target by a "tennis ball" approach. The other is based on the C-45 bowl-like trindane trimer 17 which could be capped by a C-15 lid to afford 18 prior to dehydrogenation. Progress along these routes is reported and the two relevant but "off-route" C-45 compounds 19 and 24 are described, their structures being determined by X-ray crystallographic methods.