1,1,4,4,7,7-HEXAMETHYLCYCLONONANE - SYNTHESIS AND CRYSTAL-STRUCTURE

1,1,4,4,7,7-Hexamethylcyclononane (2) has been synthesised by PtO2-catalysed hydrogenation of tris-trans-homobenzene (1) at room temperature. 2 is a crystalline compound with m.p. 85-degrees-C whose structure has been determined by a crystal structure analysis. This reveals a twisted boat-chair conformation (TBC) of approximate D3 symmetry for 2 with the gem-dimethyl groups bonded to carbon atoms lying on one of the three C2 axes of that form. The same conformation for 2 is also found in solution at room temperature by inspection of its H-1 and C-13 NMR spectra.