Phosphine oxides chlorophosphine

The hydrolysis of tervalent phosphorus acid derivatives with two P—C bonds leads to secondary phosphine oxides (50) and with one P—C bond to phosphonus acid derivatives (51). Chlorophosphines react rapidly with water, but aminophosphines, phosphinites and phosphonites often survive a short wash with aqueous NaHC03, an effective way to remove contaminating ammonium salts in the crude products. However, aminophosphines with small substituents, e.g. dimethylaminodimethylphosphine, aryl phosphinites and phosphonites and trimethylsilyl phosphinites and phosphonites are hydrolysed too quickly for such a treatment. The hydrolyses are catalysed by acids (the hydrolyses of phosphinites and phosphonites are also catalysed by OH ) and are much faster than hydrolyses of the corresponding phosphoryl compounds [up to a factor of 10 for acid-catalysed hydrolysis of (MeO)3P compared with (MeO)3P=0 ]. Dialkyl phosphonites are rapidly hydrolysed to the monoalkyl esters (51, X = OR) in weakly acidic water, whereas hydrolyses to phosphonous acids require reflux with strong acid or base, e.g. equation 131 Bis-(dialkylamino) phosphines may also be partially hydrolysed to phosphonous acid amides (51, X = NR2). Tervalent phosphorus acid derivatives with hydrogen sulphide give secondary phosphine sulphides or phosphonodithious acids, e.g. equation 156 . ... 

A few papers have reported the use of various aluminium-based reducing agents in phosphine synthesis. Lithium aluminium hydride reduction of phosphine oxide precursors provides a route to new 2-phosphinomethyl-1/7-pyrroles and diisobutylaluminium hydride (DIBAL) has been found to be an excellent reagent for the reduction of phosphinites, phosphinates and chlorophosphines. 2-Chloroethylphosphine (CICH2CH2PH2) has been prepared for the first time by a chemoselective reduction of diethyl 2-chloroethylphosphonate with dichloroalane (HAICI2), prepared in situ from LiAlH4 and AlCls. A patent has described the use of metallic aluminium... 

The most satisfactory laboratory preparation of (6.236) involves addition of an alcohol or phenol to a dialkyl or diaryl chlorophosphine in the presence of a base such as pyridine or triethylamine (6.237). This reaction is carried out in anhydrous ether near 0°C, the low temperature being necessary to prevent isomerisation of reactive products to phosphine oxides (6.108). 

Aiming at bifunctionalized allenes, alkynols were phosphorylated with diphenyl-chlorophosphine. The resulting intermediate underwent a spontaneous [2,3]-sigma-tropic rearrangement in the presence of hydrochloric acid as catalyst to afford the corresponding allenyl phosphine oxide that was converted in two steps to the sulfonyl derivative (Scheme 17). ... 

Secondary phosphines, R2PH, can be chlorinated under controlled conditions to give the corresponding chlorophosphines. These compounds can be further oxidized in a number of ways (Scheme 30). The reaction of chlorodiphenylphosphine with dibenzoyl peroxide gives diphenylphosphinic acid... 

A number of examples of reactions of chlorophosphines with ethylene oxide have been published. Thus the phosphines (34)—(36) are each converted into P chloroethoxy-derivatives, presumably by nucleophilic attack at phosphorus by the epoxide oxygen. 

Miscellaneous Reactions.—-Mixed alkylalkoxydiphosphines (103) have been prepared from secondary phosphites and chlorophosphines under basic conditions the alternative reaction between secondary phosphine and chloro-phosphite gave much lower yields. Surprisingly, oxidation of (103) with... 

It is likely that the reaction of bis(chloromethyl)chlorophosphine with benzaldehyde in wet dioxan to produce the oxide (48) involves the initial hydrolysis of the phosphine, to give (49), which adds to benzaldehyde (Scheme 11). ... 

Kolodiazhnyi and Grishkun and simultaneously Fernandez, Khiar and co-workers reacted racemic chlorophosphines and their oxides with D-glu-coruranose derivatives in the presence of amines to afford the corresponding phosphinites and phosphinates 133 respectively. The nature of the base, solvent and other experimental conditions determined the sense and degree of stereoselectivity but for some cases optically pure compounds were obtained. 

The synthesis of mixed bisphosphorus compounds has been reported by Montchamp (Scheme 4.170) [259]. His approach entailed the treatment of an alkylphosphonate precursor with a strong base at low temperatures followed by addition of a chlorophosphine or chlorophosphite to generate the bisphosphorus species. The final step in the process involved trapping the phosphine or phosphinate with BH to prevent oxidation. The chemistry was successful with a range of substrates, and moderate to excellent yields of the bisphosphorus species were obtained. The resulting compounds are valuable intermediates in the construction of complex organic compounds, and this work provides a straightforward approach to their synthesis. 

Even with the use of a glovebox, partial oxidation of the phosphine was still observed following workup of the reaction While following a Grignard approach for the synthesis of a phosphine, other parts of the molecule are being metallated instead of the chlorophosphine... 

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