Syntheses and reactivities of disubstituted and trisubstituted fluorous pyridines with high fluorous phase affinities: solid state, liquid crystal, and ionic liquid-phase properties.

摘要: Reactions of 2,6-dibromo-, 3,5-dibromo-, and 2,4,6-tribromopyridine with IZnCH2CH2Rf8 (Rf8 = (CF2)7CF3) in THF at 65 °C the presence trans-Cl2Pd(PPh3)2 (5 mol %) gave fluorous pyridines 2,6- 3,5-NC5H3(CH2CH2Rf8)2 (1 2; 85%, 31%) 2,4,6-NC5H2(CH2CH2Rf8)3 (3, 61%). Reaction 2,6-pyridinedicarboxaldehyde [Ph3PCH2CH2Rf8]+I-/K2CO3 (p-dioxane/H2O, 95 °C) 2,6-NC5H3(CHCHCH2Rf8)2 (95%; 70:30 ZZ/ZE), which was treated H2 atm, 12 h) 10% Pd/C to yield 2,6-NC5H3(CH2CH2CH2Rf8)2 (5, 95%), a higher homologue 1. Longer reaction times afforded piperidine cis-2,6-HNC5H8(CH2CH2CH2Rf8)2 (6, 98%). The stereochemistry established by NMR analysis N-benzylpiperidine. Pyridines 1−3 5 are low-melting white solids CF3C6F11/toluene partition coefficients (24 93.8:6.2, 93.9:6.1, >99.7:<0.3, 90.4:9.6, respectively 93.6:6.4). 1 CF3SO3H pyridinium salt, Cl2Pd(NCCH3)2 (0.5 equiv) yielded trans-Cl2Pd(1)2. crystal structure t...