New C3v-symmetrical tribenzotriquinacenes bearing extended and oxy-functionalised alkyl groups at their benzhydrylic bridgeheads

Abstract

A series of tribenzotriquinacene derivatives bearing three oxy-functionalised alkyl groups at the benzhydrylic bridgeheads (C-4b, C-8b and C-12b) have been synthesised. The 4b,8b,12b-triallyl derivative was used to generate the corresponding TBTQ-tris-acetaldehyde and TBTQ-tris(acetic acid), in which the functional groups stretch out from the convex rigid molecular surface. The corresponding tribromo derivate was found to undergo smooth Lewis acid-catalyzed C–C coupling with appropriate silyl enol ethers to afford a series of threefold 4b,8b,12b-(2-oxoalkyl)-substituted tribenzotriquinacenes. Six-fold nitration at the arene periphery was performed with 4b,8b,12b-tripropyltribenzotriquinacene and with the TBTQ-tris(acetic acid) to check for the effect of the bridgehead groupings as solubilising auxiliaries.