Butadiyne-bridged - and metacyclophanes having exo-annular t-butyl groups were prepared by intermolecular Eglinton coupling of the dimeric unit or by intramolecular ring closure of the linear tetramer. Comparison of the 1H and 13C NMR spectra of metacyclophane with those of cyclophane and diphenylbutadiyne revealed its prominent geometrical feature due to deformation of the triple bonds from linearity. The Metacyclophane was converted into thiophenometacyclophane in good yield by treatment with sodium sulfide.
- Coupling reactions
- Strained compounds