A General Method for High-Pressure-Promoted Postfunctionalization of Unclosed Cryptands: Potential Phase-Transfer Catalysts

We report a high-pressure approach to facile late-stage
functionalization
of unclosed cryptands (UCs) (11 examples, yield up to 99%). Direct
comparison of classic and high-pressure conditions of the quaternization
reaction in a sterically crowded intraannular position is investigated,
and differences in the reactivity of tertiary amine substrates are
discussed. Finally, we demonstrated the application of UCs as catalysts
for synthetically important alkylation reactions under phase-transfer
conditions.