"Click" Methodology for Synthesis of Functionalized [3]Catenanes: Toward Higher Interlocked Structures

A study was conducted to demonstrate the use of 'click' methodology for synthesizing higher interlocked structures of functionalized [3]catenanes. The strategy was based on the separate threading of two phenanthroline string-like fragments, containing terminal azido groups and alkynyl moieties. The synthesis was performed through a functionalized coordinating macrocycle, using the copper(I) template approach. It was found that 'double-click' reaction and demetalation afforded bis-functionalized [3]catenanes. A heterogeneous medium composed of CH2Cl2 and H2O/EtOH was used to overcome the precursor stability problem of the methodology. 'Click' additives, such as sulfonated bath-ophenanthroline (SBP) and 1,8-diaza[5.4.0]bicycloundec- 7-ane (DBU) were used to enhance the reaction kinetics and prevent dissociation.