Towards the total synthesis of cyclo[n]carbons and the generation of cyclo[6]carbon

We describe efforts towards the synthesis of some allotropes of carbon, the cyclo[n]carbons where 18, 24 and 30. The key intermediate 11 is hexa-1,3,5-triyne with the central triple bond masked as a 1-amino-1,2,3-triazole derivative. Cyclo-oligomerisation of this by oxidative coupling gives macrocyclic precursors of C-18, C-24 and C-30. C-30 is a proposed intermediate in the formation of C-60 and we also describe some attempts at the synthesis of C-60 via the chemical generation of benzotriyne, cyclo[6]carbon.