Syntheses and Structures of 1,8,13,16-Substituted Triptycenes

New triptycene derivatives have been synthesised based on the cycloaddition between 1,8-bis[(trifluoromethanesulfonyl)-oxy]anthracene as well as 1,8-bis[(trimethylsilyl)ethynyl]anthracene and p-benzoquinone. The resulting triptycenequinones were the key compounds for further functionalisation of the triptycene backbone, which were completely characterised by multinuclear NMR spectroscopy, mass spectrometry and X-ray diffraction experiments. The aim was to substitute the triptycene backbone in positions 1, 8, 13 and 16 to avoid the formation of mixtures of syn- and anti-isomers of trisubstituted triptycenes. Based on the ditriflate-substituted triptycenequinone triptycene 1,8,13,16-tetratriflate was synthesised and reacted with alkynyl compounds in cross-coupling reactions. In further experiments the alkynyl-substituted triptycene to quinone was directly reacted with lithiated trimethylsilylacetylene or was initially reduced, consequently functionalised with triflate groups and reacted in Sonogashira cross-coupling reactions. It was found that both reaction pathways generate the anti-substituted product in position 16 as main product.