1,1,4,4,7,7-Hexamethylcyclononane: synthesis and crystal structure

Abstract

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 °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 ¹H and ¹³C NMR spectra.