Synthesis of a Double-Spanned Resorc[4]arene via Ring-Closing Metathesis and Calculation of Aggregation Propensity

Ring-closing metathesis (RCM) catalyzed by a second-generation Grubbs catalyst has been used to synthesize resorc[4]­arenes 2b–5b starting from undecenyl resorc[4]­arene 1b fixed in the cone conformation. X-ray diffraction analysis of the major metathesis product, 3b (50% yield), revealed a cavity-shaped architecture resembling a basket, endowed with a large intramolecular space (∼10 Å) and a strong propensity to self-assemble as a supramolecular trio of heterochiral dimers. This prompted us to investigate the aggregation propensity of basket 3b in THF/water solution by UV–visible spectroscopy. The cavitation Gibbs free-energy change (ΔΔGcav = 4.78 kcal mol–1) associated with the self-assembly of macrocycle 3b was calculated as a measure of the solvophobic interactions involved in the process.