Synthesis and Chemistry of Acyclic Mono- and Disiloxanes: Useful Precursors to Per- and Polyfluoroethers

Abstract

Acyclic polyfluoro mono and disiloxanes CF3CH2OSiMe3 (1), CF3C(CH3)2OSiMe3 (2), CH3C(CF3)2OSiMe3 (3), C6H5C(CF3)2OSiMe3 (4), (CF3)2CHOSiMe3 (5), (CF3)3COSiMe3 (6), FCH2CH2OSiMe3 (7), HCF2CF2CH2OSiMe3 (8), n-C7Fi5CH2OSiMe3 (9), (CF2CH2OSiMe3)2 (10), and CF2(CF2CH2OSiMe3)2 (11) are synthesized by the reactions of their respective alcohols with hexamethyldisilazane. Reactions of 1 with CH2Br2, (CNF)3, CFBr3, perfluorocyclobutene, and C6F5CN proceed readily in the presence of fluoride ion to form CH2(Rf)2 (12), C3N3(Rf)3 (13), C(Rf)4 (14), CF2C(Rf)=C(Rf)CF2 (15), CF2C(Rf)=C(F)CF2 (16) and 4-RfC6F4CN (17) (when reacted 1:1) and (Rf)5C6CN (18) (when reacted with excess of 1), respectively (Rf = OCH2CF3). Reactions of 2 with C6F5CN, C6F6, CF3C6F5, ClCeF5, NC5F5,1,2-diiodotetrafluorobenzene and perfluorocyclobutene in the presence of fluoride ion give RfC6F4CN (19) or (Rf)2C6F3CN (20) (depending on the ratio of reactants), RfC6F5(21), RfC6F4CF3 (22), RfC6F4Cl (23), RfC5F4N (24), RfC6F3I2 (25), and [formula omitted] (26), respectively (Rf = CF3C(CH3)2O). Reactions of 3 with C6F5CN, C6F6 and 1,2-diiodotetrafluorobenzene with fluoride ion as catalyst form RfC6F4CN (27), RfC6F5 (28) and RfC6F3I2 (29), respectively (Rf = CH3C(CF3)2O). Reactions of 4 with CF3C6F5, C6F5CN, perfluorocyclobutene, C6H5CH2Br and CH3I give RfC6F4CF3 (30), RfC6F4CN (31), CF2C(Rf)=C(F)CF2 (32), RfCH2C6H5 (33) and RfCH3(34), respectively (Rf = C6H5C(CF3)2O). Reactions of 5 with C6F5CN and CF3C6F5 result in RfC6F4CN (35) and RfC6F4CF3 (36), respectively (Rf = (CF3)2CHO). Siloxanes 6, 7, 8 and 9 with C6F5CN form CNC6F4OC(CF3)3 (37), FCH2CH2OC6F4CN (38), HCF2CF2CH2OC6F4CN (39) and n-C7F15- CH2OC6F4CN (40). Disiloxane 10 with CH2Br2, Br2CHCHBr2, SOF2, SO2Cl2, COF2, C6F5CN, (COF)2, POCl3, C5F5N, CF3SO2F, 1,2-diiodotetrafluorobenzene, I(CF2)2O(CF2)2SO2F, FC(O)(CF2)3C(O)F and 1,4-dibromo-I-1 Itetrafluorobenzene gives polyfluorinated cyclic or acyclic ethers CF2CH2OCH2OCH2CF2 (41), CF2CH2-OCHOCH2(CF2)2CH2OCHOCH2CF2 (42), CF2CH2OS(O)OCH2CF2 (43), CF2CH2OSO2OCH2CF2 (44), FC(O)OCH2- CF2CF2CH2OC(O)F (45), 4-CNC6F4OCH2CF2CF2CH2OC6F4CN-4 (46), CF2CH2OC(O)C(O)OCH2CF2 (47), CF2CH2OP(O)FOCH2CF2 (48), NC5F4OCH2CF2CF2CH2OC5F4N (49), CF3SO2OCH2CF2CF2CH2OSO2CF3 (50), F2CH2CO(3,6-difluoro-4,5-diiodo-o-phenylene)OCH2CF2 (51), I(CF2)2O(CF2)2SO2OCH2(CF2)2CH2OSO2(CF2)2OCF2)2I (52), CF2CH2OC(O)(CF2)3C(O)OCH2CF2 (53), and (-F2CH2CO)2(3,6-dibromo-1,2,4,5-benzenetetrayl)(OCH2- CF2−)2 (54), respectively. Reactions of 11 with CH2Br2, COF2, SOF2, and SO2Cl2 also give cyclic and acyclic ethers CF2CF2CH2OCH2OCH2F2 (55), FC(O)OCH2(CF2)3CH2OC(O)F (56), CF2CF2CH2OS(O)OCH2CF2 (57), and CF2CF2CH2OSO2OCH2CF2 (58), respectively. Ethers 17, 38-40 and CH3CH(CF3)OC6F4CN (59) are also prepared by reacting the corresponding alcohols with pentafluorobenzonitrile in the presence of alkali carbonate as the HF- acceptor. Reaction of C5H5OSiMe5 with C6F5CN yields the polyether (C6H5O)5C6CN (60). When ethers 17, 38–40 and 59 are hydrolyzed in alkaline hydrogen peroxide (30%), the corresponding benzamides CF3CH2OC6F4CONH2 (61), FCH2CH2OC6F4CONH2 (62),HCF2CF2CH2OC6F4CONH2 (63), n-C7F15CH2OC6F4- CONH2 (64) and CH3CH(CF3)OCeF4CONH2 (65), respectively, are formed. © 1994, American Chemical Society. All rights reserved.