Aqueous conditions cationic phosphines

Using RuCl(CO)(TPPTS)(BISBIS) the biphasic aqueous hydroformylation of higher olefins in the presence of the cationic surfactant CTAB ensures a TOF > 700 h and regioselectivity >96% for the linear aldehyde Piperazinium cationic surfactants were also successfully applied as catalysis promotion agents in the aq. biphasic hydroformylation of higher olefins. The property of surfactant and ligand can be assumed by the same molecule, e.g. di-sulfonated cetyl(diphenyl)phosphine 42. 1-Dodecene is hydroformylated in water/toluene (3 1) under mild conditions [olefin/Ru = 2500, CO/H2=1, P(CO + H2) = 15 bar, 42/Ru = 10] with TOF = 188 Another approach to... 

As pointed out above, nucleophiles such as sulfides, alcohols, amines, phosphines, halides, and halide ions readily attack sulfur radical cations forming S.-.S, S.-.O, S.-.N, S.-.P, and S.-.X species. Generation of Me2S , under pulse radiolysis conditions, by the reaction of Me2SO with H- in aqueous HC104 permitted the... 

Synthesis of the modified triphosphate subunit was accomplished starting from ethyl bis(bromomethyl)phosphinate 253 (Scheme 51). An Arbusov reaction with triethyl phosphite and trimethyl phosphite, respectively, produced bis (phosphonomethyl)phosphjnate 255 in 40% overall yield. A selective monodemethylation by cyanide and acidificaticHi led to monophosphonic acid 256. Bismethylene triphosphate (BMT) 258 analogues of nucleosides were obtained by coupling of the 5 -free OH nucleosides 257 with phosphonate 256 under Mitsunobu conditions [181,182]. TMSBr mediated deprotection followed by treatment with aqueous anmumia and cation exchange afforded bismethylene analogues 259 of nucleoside triphosphate in yields up to 62%. 

Another class of compounds whose cations may not be precipitated by the addition of hydroxide ions are the most stable complexes of metal cations with Lewis bases, such as ammonia, amines, and tertiary phosphines. Because of the large number of these compounds and their wide range of properties, it is not possible to give a general procedure for separating the cations. In many cases, metal sulfides can be precipitated directly from aqueous solutions of the complexes by the addition of aqueous sodium sulfide. If a test-tube experiment shows that other measures are needed, the addition of hydrochloric acid to produce a slightly acidic solution will often decompose the complex by protonation of the basic ligand. Metal ions that form insoluble sulfides under acid conditions can then be precipitated by drop wise addition of aqueous sodium sulfide. 

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