Active Metal Template Synthesis of Rotaxanes From BINOL-Phosphate Macrocycles

We demonstrate the use of macrocyclic BINOL-phosphates for the active metal template synthesis of [2]rotaxanes via Cu(I)-mediated alkyne-azide cycloaddition. This novel methodology represents a key extension of the current active metal template approach beyond nitrogen-based macrocycles and allowed for the synthesis of 17 differently functionalized chiral rotaxanes in yields up to 93%. Mechanistic studies combining DFT calculations, control experiments, and kinetic experiments support a dinuclear phosphate-Cu₂ intermediate, which makes the formation of the rotaxanes kinetically competitive. Enabled by this novel methodology, we prepared both diastereomers of highly functionalized interlocked bis-BINOL rotaxanes.