Reactions of p-BrC6H4CH=O with Wittig reagents derived from [Ph3PCH2CH2Rfn]+ I- (Rfn = (CF2)n-1CF3; n = 6 (6a), 8 (6b), 10 (6c)) give p-BrC6H4CH=CHCH2Rfn (86-93%), which are treated with H2 and Wilkinson's catalyst to yield p-BrC6H4(CH2)3Rfn (91-94%). Reactions with n-BuLi and PCl3 (0.33 equiv) give, after workup, mixtures of the title compounds (9a-c) and the corresponding phosphine oxides (10a-c). Treatment with H2O2 gives pure 10 (a/b/c 88/57/24%), which are reduced with Cl3SiH/Et3N to 9 (a/b/c 69/82/43%). Fluorous phase affinities increase with perfluoroalkyl chain length, as quantified by CF3C6F11toluene partition coefficients (9a, 19.5:80.5; 9b, 66.6:33.4). Reaction of 9b, [Ir(COD)(μ-Cl)]2, and CO gives trans-Ir(CO)(Cl)[P(p-C6H4(CH2)3 Rf8)3]2 (76%). The IR νCO value is only slightly greater than that of Vaska's complex (1958 vs 1952 cm-1), indicating nearly negligible inductive effects of the perfluoroalkyl groups. Reaction of 9b and [Rh(COD)(μ-Cl)]2 yields Rh[P(p-C6H4(CH2)3 Rf8)3]3(Cl) (82-93%), which gives small equilibrium amounts of [Rh[P(p-C6H4(CH2)3 Rf8)3]2(μ-Cl)]2 and 9b in solution, and catalyzes the hydrogenation of alkenes under both biphasic (CF3C6F11/toluene) and monophasic (CF3C6H5) conditions.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Organic Chemistry
- Inorganic Chemistry