Phosphine preparation

This can be extracted from impure phosphine prepared by the action of sodium hydroxide on phosphorus. Unlike hydrazine, it has no basic properties. It is a powerful reducing agent and burns spontaneously in air, this reaction explaining why impure phosphine containing traces of diphosphane ignites spontaneously in air. 

For general application of these chiral ligands, see (a) Kagan, H. B. Chiral Ligands for Asymmetric Catalysis in Morrison, J. D. ed. Asymmetric Synthesis, vol. 5, Chap. 1, Academic Press, New York, 1985. (b) Kagan, H. B., Sasaki, M. Optically Active Phosphines Preparation, Uses and Chiroptical Properties in Hartley, F. R. ed. The Chemistry of Organo Phosphorous Compounds, John Wiley Sons, New York, 1990, vol. 1, Chap. 3. 

Work in the polymer synthesis area has been enhanced by a convenient "one-pot" synthesis which was developed by J.C. Wilburn ( ) (eq 1). Yields of the phosphines prepared in this manner are typically 60 to... 

The most direct synthesis is performed by reaction of a dihalo compound with a tricoordinated phosphorus compound including a reactive P—Y bond (reaction 101). This synthesis, first used with secondary phosphines, the corresponding phosphides or diphosphines (Y = H, Na, K, PPh2)2b,38°, has subsequently been developed also with silylphosphines (Y = SiMe3),132,381-383 which are easier to handle (reaction 102). The same kind of cyclization by intramolecular alkylation can be achieved using a functional phosphine prepared in a multi-step synthesis380,384,385 (reaction 103). 

Cr PS, TG phosphine preparation of resin-bound chromium(II) carbene complexes [67]... 

Phosphine prepared by this method exhibits a vapor pressure of 170 1 mm. at —111.6°C. (CS2 slush). The literature value is 171 mm.8 Infrared9 and mass spectral10 data have been reported. The infrared spectrum shows t pH at 2327 cm.-1 and also peaks at 1121 and 900 cm.-1. In the gas phase, all these bands show complex fine structure. 

Preparation of 4-acetoxybutylzinc iodide and its addition to dichloro(diethylamino)phosphine preparation of di(4-acetoxybutyl) (diethylamino)-phosphine-borane complex10... 

Chemists who wish to prepare enantiomerically pure phosphines should consult the excellent review by Pietrusiewics and Zablocka,45 which gives examples of most of the P-chiral phosphines that have been made efficiently. In the last 10 years, a number of effective asymmetric syntheses of P-chiral phosphines have been developed. Prior to this, many of the chiral phosphines prepared were synthesized in racemic form and then resolved using stoichiometric amounts of a chiral organic compound or chiral palladium, platinum, or iron complexes. Although some interesting phosphines have been prepared by this method, they are not mentioned here as the experimental procedures are not in widespread use. 

Relatively few applications of optically active tertiary arsines to asymmetric synthesis have been reported by comparison with the extensive work with phosphines . Authoritative accounts of the synthesis and stereochemistry of compounds of Group V elements are available other reviews cover the subject up until 1979 . For general treatments of organoarsenic chemistry up until 1976, including optically active compounds, two important works are available . Of related interest is an article on stereochemical aspects of phosphorus chemistry and another published in this series on optically active phosphines preparation, uses and chiroptical properties . On matters concerning the intricacies of resolutions work, the reader should consult Reference 21, especially Chapter 7, which is entitled Experimental Aspects and Art of Resolutions. 

Potassium organophosphide reagents also continue to find applications in synthesis. Direct displacement of fluoride from fluoroaromatic substrates by potassium diphenylphosphide is the key step in the synthesis of the phosphi-noarylsulfoxides (88), water-soluble phosphino-amino acid systems, e.g. (89), ° and the chiral benzoxazine system (90). Related displacement of fluoride by potassium monophenylphosphide has been used to prepare a series of hydrophilic triarylphosphines, e.g. (91). Among new phosphines prepared by conventional displacement reactions by potassium diphenylphosphide on... 

Among new phosphines prepared via reactions of phosphines coordinated to metal ions are the diphosphinonaphthalenes (175), and the iminophosphine (176). ... 

Fig. 5. Pmr spectrum of the (/ )p diastereomer of deuteriomenthyi methylphenyl-phosphinate prepared from 11, T scale...

For reviews on chiral phosphines prepared for homogeneous asymmetric catalysis, see Ref. 6, 6, and 26. 

Y. Utah, Y. Sasson, I. Shahak, S. Tsaroom, and J. Blum, A new aziridine synthesis from 2-azido alcohols and tertiary phosphines. Preparation of phenanthrene 9,10-imine, J. Org. 

T ris(trimethylsilyl)phosphine -, preparation 23,646s44 T ris(trimethylsilyl)silane... 

This method was described for the first time in the accounts of Mislow and co-workers ° and of Nudelman and Cram. " " These reports are classical papers in P-stereogenic chemistry. Table 2.8, which is not comprehensive, lists some of the phosphines prepared in the early reports about this method. 

Entries 1-22 list exo phosphines 200 whereas entries 23-30 are endo phosphines 203 (Scheme 2.62). The number of endo phosphines prepared to date is more limited, probably due to the low stereoselectivity in their formation. Entries 1-10 include exo monophosphines with additional oxygen (entries 1-6), sulfur (entries 3, 5-8) and nitrogen (entries 9 and 10) donor atoms. Entries 11-22 contain a second phosphorus or an arsenic atom, which in some cases is also stereogenic (entries 14-16 and 19 21). The compound in entry 19 is the dimerisation of DMPP, which required the use of a platinum complex. ... 

Table 2.15 P-stereogenic phosphines prepared by Pd-promoted Diels-Alder reactions.

Despite its versatility, the ephedrine methodology clearly suffers from some limitations. Exceedingly bulky phosphines (bearing mesityl or 9-anthryl groups for example) can only be prepared in low yields if at all. This is because the method is based on nucleophilic substitutions at the phosphorus atom, which become progressively more difficult with increased steric shielding. Another limitation is that all the phosphines prepared bear at least one aryl group (almost exclusively phenyl) and are therefore very basic, trialkylphosphines are not accessible via the ephedrine method. This limitation has been partially overcome by another complementary and extremely important method the enantioselective deprotonation of dimethylphosphine derivatives described in detail in the next chapter. 

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