Silacrowns: Phase Transfer Catalysts

The synthesis, solubility enhancement, and phase-transfer catalysis properties of cyclic poly(alkyleneoxy)silanes (silacrowns) I [R = R1 = Me; R = Me, R1 = Et, Ph, CH2:CH, MeO, H2NCH2CH2NH(CH2)3; n = 3-6] are described. Solubility enhancements of Li, Na, and K ions are a function of macrocycle and ion size. Phase-transfer catalysis of acetate, azide, cyanide, fluoride, and nitrite ions in displacement reactions are reported.
keywords: crown ether; ion transport; phase transfer catalysis; organosilicon chemistry