HIGHLY DISTORTED CONE CALIX[4]ARENES THROUGH INTRAMOLECULAR MCMURRY COUPLING REACTION

Highly distorted and rigid cone conformers of calix[4]arene have been synthesized by low-valent titanium promoted intra-molecular coupling o f aldehydes 1a-d. The reaction outcome strongly depends on the substit uents present at the upper rim and reaction time. In all cases examine d intramolecular coupled compounds, having a bridge only two atoms lon g, were obtained in about 30% yield.