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

Abstract

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.

Triptycene Derivatives: From Their Synthesis to Their Unique Properties

“…Another approach aimed at regioselective synthesis of triptycene derivatives was presented by the group in 2018—Shwartzen et al used cycloaddition of 1,4-benzoquinone to substituted anthracenes for the preparation of triptycenes functionalized with triflate or C≡C-SiMe 3 groups ( Scheme 2 b)[ 120 ].…”

“… Studies on the regioselectivity of the synthesis of ortho -substituted triptycenes by the Mitzel group: ( a ) the electronic character of a substituent on C10 influences the syn / anti ratio of the product [ 119 , 120 ]; ( b ) triptycenes functionalized with triflate or (trimethylsilyl)ethynyl groups [ 120 ]. …”

Chalice‐Type Tridentate Silicon Lewis Acids of C3 Symmetry in a Single Step Starting from Hexadehydrotribenzo[12]annulene

“…For bidentate Lewis acids we used for instance dialkynylanthracenes [15] or diphenyldiethynylsilanes, [16] diphenyldiethenylsilanes as well as diphenyldiethylsilanes [17] to carry two acid functions like B(C 6 F 5 ), AlR 2 , GaR 2 and InR 2 (R=Me, Et). Tris‐Lewis‐acids were realized with trifunctional skeletons including the bowl‐shaped tribenzotriquinacene, [18] tris‐( ortho ‐phenyl)‐silane, [19] 1,8,13‐substituted triptycenes [20] or all‐ cis ‐1,3,5‐triethynyl‐1,3,5‐trisilacyclohexane [21] carrying the Lewis acid groups. And recently we succeeded in the synthesis of a tetrafunctional Lewis acid with four parallel oriented diphenylboranylethynyl functions attached to the same side of an anthracene dimer.…”