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 fi xed 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 ( ?? Gcav = 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.