Reversible synthesis of π-associated [2]catenanes by ring-closing metathesis: towards dynamic combinatorial libraries of catenanes

Ring-closing metathesis of aromatic diimides substituted with olefin-terminated alkyl chains in the presence of a dinaphtho crown ether affords neutral [2]catenanes. Templating π-donor/π-acceptor interactions are exploited to drive mechanical interlocking and favour production of the more thermodynamically stable catenane products. Structure proof was provided by single-crystal X-ray synchrotron diffraction of a representative catenane.