Per- and Polyfluoroaryl Mono- and Disiloxanes as Transfer Reagents in the Synthesis of Highly Fluorinated Mono- and Diethers

Abstract

In the presence of fluoride ion, per- or polyfluoroaromatic siloxanes C6F5OSi(CH3)3 (1), (CH3)3SiOC6F4OSi-(CH3)3 (2), l-fluoro-2, 3-bis((trimethylsilyl)oxy)benzene (3), and (CH3)3SiOC(CF3)2C6F4C(CF3)2OSi(CH3)3 (4) are useful transfer reagents for the synthesis of mono- and diethers. Siloxane 1 forms RfOCF2Br (5), (RfO)3CF (6), RfOCH2ORf (7), (RfO)2CHCH(ORf)2 (8), (RfO)2SO (9), (RfO)2CO (10), C3N3(ORf)3 (11), RfOC(O)-(CF2)3C(O)ORf (12), CF3SO2ORf (13), CF2C(ORf)=C(ORf)CF2 (14), and CF2C(ORf)=C(F)CF2 (15) (Rf = C6F5) with CF2Br2, CFBr3, CH2Br2, Br2CHCHBr2, SOF2, COF2, (CNF)3, ClC(0)(CF2)3C(O)C1, CF3SO2F, 1, 2-dichlorotetrafluorocyclobutene, and perfluorocyclobutene, respectively. Compound 5 is readily converted to C6F5-OCF2Si(CH3)3 (16) with hexaethylphosphorous triamide and (CH3)3SiCl in benzonitrile. With C6F5CN, CF3C6F5, C5F5N, CH3I, perfluorocyclobutene, CF3C(O)Cl and (CNF)3, 2 forms diethers p-CNC6F4OC6F4OC6F4CN-p (17), p-CF3C6F4OC6F40C6F4CF3-p (18), NC5F4OC6F4OC5F4N (19), CH3OC6F4OCH3 (20), and C2F5C(O)OC6F4OC-(O)C2F5 (21), respectively. Reaction of 3 with 1, 2-diiodotetrafluorobenzene in diglyme gives 1, 4, 8-trifluoro-2, 3-diiodophenozine (22). Disiloxane 4 with C6H5CH2Br, CH3I, C6F5CH2Br, and COF2 results in C6H5CH2OC-(CF3)2C6F4C(CF3)2OCH2C6H5 (23), CH3OC(CF3)2C6F4C(CF3)2OCH3 (24), C6F5CH2OC(CF3)2C6F4C(CF3)2OCH2C6F5 (25), and C(O)OC(CF3)2C6F4C(CF3)2OC(O)OC(CF3)2C6F4C(CF3)2O (26), respectively. These materials are thermally and hydrolytically stable and are formed in high yields. © 1995, American Chemical Society. All rights reserved.