A Molecular Cage Accessed by Threefold Click Reaction of a -Symmetric Triazido-Functionalized Tribenzotriquinacene.

The hitherto unknown hexakis(halomethyl)-functionalized tribenzotriquinacenes (TBTQs) and were synthesized from the key 4b,8b,12b-tribromo-TBTQ derivative by an improved route in 67% overall yield. Extension of the bowl-shaped framework of or by threefold condensation with propargylamine or 2-azidoethylamine afforded the corresponding TBTQ-trialkyne and TBTQ-triazide , respectively. While attempts to construct bis-TBTQ cages, including homodimerization of and heterocoupling of with , were unsuccessful, triazide was found to undergo threefold [3 + 2]-cycloaddition with 3-ethynylaniline and phloroglucinol tripropargyl ether under click chemistry conditions. The latter reaction enabled facile capping of the TBTQ bowl to give the novel cage compound in 22% yield.