Quaternary phosphorus compounds

In these early days, only quaternary phosphorus compounds were resolved. Ethylmethylphenylphosphine oxide (1) constitutes the first ever racemic F-stereogenic compound separated into individual enantiomers in 1911 by Meisenheimer and Lichtenstadt. It took 15 years for the same laboratory to repeat that feat and apply the same method to resolve benzylmethylphenyl-phosphine oxide (2). In 1944 sulfide 3 was resolved by Davies and Mann and 15 years later McEwen and co-workers" resolved the first acyclic phosphonium salt (4). 

Partitioning of carbocations between addition of nucleophiles and deprotonation, 35, 67 Perchloro-organic chemistry structure, spectroscopy and reaction pathways, 25, 267 Permutational isomerization of pentavalent phosphorus compounds, 9, 25 Phase-transfer catalysis by quaternary ammonium salts, 15, 267 Phosphate esters, mechanism and catalysis of nucleophilic substitution in, 25, 99 Phosphorus compounds, pentavalent, turnstile rearrangement and pseudoration in permutational isomerization, 9, 25... 

P. Beck, Quaternary Phosphonium Compounds, in Organic Phosphorus Compounds, G. M. Kosolapoff and L. Maier, (eds.), Vol. 2, John Wiley-Interscience, New York, 1972, Chap. 4. 

Separation by solvent extraction Uranium can be extracted from aqueous solutions using extraction agents into the solvent phase, from which it can be stripped. The extraction agents used are phosphorus compounds such as di-(2-ethylhexyl)-phosphate, tri-n-butyl-phosphate and tri-n-octylphosphine oxide as well as primary, secondary and tertiary amines in salt form or as quaternary ammonium salts. The extraction agents are diluted with inert hydrocarbons, preferably kerosene, to concentrations of 4 to 10% by volume. The solubility of the amine salts, particularly the hydrogen sulfates, chlorides and nitrates is increased by adding long chain alcohols (e.g. isodecanol). 

One group of fungicidal organic phosphorus compounds worthy of mention are quaternary ammonium salts of the general formula (28), which have very notable bactericidal and fungicidal properties (Melnikov et al., 1962). 

Phosphorus-containing flame retardants are suitable for polar polymers such as PVC, but for polyolefins their action is not sufficient. In this case they are used together with Sb203 and with halogenated compounds. Alkyl-substituted aryl phosphates are incorporated into plasticized PVC and modified PPO (Noryl) to a great extent for other plastics they are less important. Quaternary phosphonium compounds are recommended as flame retardants for ABS and polyolefins. 

The first asymmetric catalytic C -P bond formation employing electrophilic phosphorus compounds has been reported. By applying catalytic amounts of quinine derivative (26) in combination with the proton sponge and a subsequent one-pot process, Q -quaternary a-phosphino -amino acids were synthesized with high stereoselectivities (up to 93% ee) and good yields. On the basis of P NMR experiments... 

Baba, T. and Watanuki, Y, Nonaqueous quaternary ammonium salt electrolytic solutions containing cyclic boron or phosphorus compounds for electiolytic capacitors, JP 2007123631 (2007). 

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