Tetra-tert-butyltetraoxa[8]circulene and Its Unusual Aggregation Behaviour

We describe the first example of the synthesis of a tetraoxa[8]circulene with only four substituents by means of BF3 center dot OEt2 mediated tetramerisation of tert-butyl-1,4-benzo-quinone. Two of the four regioisomers of tetra-tert-butyltetraoxa[8]circulene have been isolated and characterised by single-crystal X-ray analysis. It was found that the tetra-tert-butyltetraoxa[8]circulenes aggregate in solution through a cooperative polymerisation mechanism despite functionalisation with bulky tert-butyl substituents.