Perfluoroalkylated 4,13-Diaza-18-Crown-6 Ethers: Synthesis, Phase-Transfer Catalysis, and Recycling Studies

摘要

A series of N,N'-dialkyl-4,13-diaza-18-crown-6 lariat ethers possessing two C_8H_(17) (2), (CH_2)_3C_8F_(17) (3), (CH_2)_3C_(10)F_(21) (4), and (CH_2)_2C_8F_(17) (5) side arms were synthesized in good yields by N-alkylation of 4,13-diaza-18-crown-6. Potassium picrate could be extracted from an aqueous solution into an organic phase by all of the perfluoroalkylated macrocycles demonstrating their potential to be used as phase-transfer catalysts, and preliminary studies on a classical nucleophilic substitution established that they each gave higher catalytic activities under solid—liquid than under liquid—liquid phase-transfer conditions. The light fluorous macrocycles gave similar, if not better, catalytic activity compared to the parent, non-fluorinated phase-transfer catalyst 2 under solid—liquid conditions in conventional organic solvents in both an aliphatic and an aromatic nucleophilic substitution. N,N'-Bis(1H, 1H,2H,2H,3H,3H-perfluoroun-decyl)-4,13-diaza-18-crown-6 (3) was recycled six times in the iodide displacement reaction of 1-bromooctane and four times in the fluoride displacement reaction of 2,4-dinitrochlorobenzene using fluorous solid-phase extraction without any loss in activity.