Rapid access to C3-and Cs-symmetric AAT organogelators via ring opening of a common benzotrifuranone precursor

Presented is a rapid and general approach to functionalised 1-aza-adamantanetrione (AAT) donor-sigma-acceptor molecules from a phloroglucinol-derived trilactone, benzotrifuranone (BTF). Ten C3-symmetric AATs bearing diverse aryl amide substituents are accessed in two synthetic steps: (1) the exhaustive ring opening of BTF with aromatic amine nucleophiles (performed in up to 91% yield) and (2) cyclisation with hexamethylenetetramine (performed in up to 75% yield). Additionally, stepwise ring opening of BTF allows synthesis of phloroglucinol intermediates with two unique aryl amide substituents and ultimately Cs-symmetric AATs. Of the novel AATs prepared, three (including the Cs-symmetric hybrid) are effective gelators of chlorinated solvents (critical gelation concentration (CGC)=0.2-0.4 wt%) and one, with naphthyl substituents, forms translucent gels from aromatic solvents (CGC0.3 wt%). The combination of AATs with moderately electron-poor and electron-rich aromatic substituents results in functional complementarity and gelation at concentrations below what is required for the individual components. Electron microscopy of the gel morphologies shows high aspect ratio fibres underlying the gel network superstructures in most cases. Polarised optical microscopy has allowed imaging of representative native organogel phases, and reveals striking morphology differences between gels that also share different optical and/or thermal stability properties.