Phosphine imine

The efficient conversion of the furazans (70) into 1,4-dinitriles (71) is thought to occur via the nitrile oxides (72). Thermal decomposition of the diaziridones (73) in the presence of triethyl phosphite gives the phosphine-imine (75) and the isocyanate (74), which subsequently react together to give the carbodi-imide (76). ... 

Acyclic phosphazenes (phosphazo derivatives, phosphine imines, phosphoranimines) continue to attract interest. A review of the three coordinate materials, RN=PR =X has appeared. " Several molecular orbital calculations have been reported. An ab initio treatment of the PN energy surface suggests that this species is best regarded as having a dative phosphorus-nitrogen double bond rather than a triple bond and the phosphonitrene, once formed,... 

In general, azides are more easily available than nitro compounds by SN2 reaction of the corresponding halides. Thus, the direct conversion of an azide into a nitro group is useful for the synthesis of nitro compounds. Corey and coworkers have reported the easy conversion of azides to nitro compounds via ozonolysis of phosphine imines (Eq. 2.70).139... 

An interesting approach to rhenium bioconjugate formation that has been developed but apparently has yet to be fully evaluated from the standpoint of applicability and stability is the use of chelating and nonchelating phosphine imine and phosphine oxide ligands [110]. For... 

Oxazaphospholidines.—The phosphoranes (72) were obtained from phosphine-imines and epoxides as shown.49 Pyrolysis gave phosphine oxide and aziridines. The... 

Addition reactions of silylphosphines to imines have been reported, 4 as illustrated for diethyl(trimethylsilyl)phosphine (70). Organic azides react with germylphosphines by an insertion pathway,65 as shown for various phenyl(trimethylgermyl)phosphines (71). The initial products (72) isomerize to phosphine imines on heating.66... 

Alternatively, phosphine imines 266 were treated with various phenylacetyl chlorides 270 (method B). Surprisingly, phosphonium salts 271 were isolated with 25 to 97% yield, which could be deprotonated by means of a base to build up the corresponding phosphoranes 272 (66-89% yield). Upon heating to... 

Cp UCl2 (Cp = C5Me5) HNPPh3 Cp2UCl2(HNPPh3) The first /-element complex with a phosphine imine ligand 483a... 

Hexafluoroacetone imine has been prepared by the reaction of hexafluoroacetone with triphenyl phosphine imine,2 by the pyrolysis of N-phenyl-2,2-diaminohexafluoropropane,23 by the reaction of hexafluorothioacetone with hydrazoic acid,4 and by the reaction of ammonia and phosphorus oxychloride with hexafluoroacetone.4,5 The latter method, which is described here, is the most convenient for it does not require preparation of several intermediates or use of pressure equipment. This method has also been used to prepare the imines of other Huoroketones, including the imines of chloropentafluoroacetone, dichlorotetrafluoroacetone, and perfluorodiethyl ketone.5 Substitution of methylamine for ammonia in this procedure gives the N-methyl imine.5... 

Primary and secoiidary nitroalkanes. A new route to nitro compounds involves conversion of azides to phosphine imines by reaction with triphenyl- or tri-n-butylphos-phine at 25—35° followdd by ozonolysis in CHiCE at — 78°. Presumably the initial ozonidc is converted into a nitfoso compound, which is then oxidized to the nitro compound... 

A study of the mechanism of this catalytic process revealed that the reaction proceeds by two [2-1-2] cycloaddition sequences via a phosphine imine (iminophosphorane) intermediate... 

The reaction is first order with respect to isocyanate and catalyst, and the reaction of the phosphine imine with isocyanate is the slow, rate determining process. 

Reaction of the same benzotriazole with thiolate in the presence of sodium or lithium, followed by reaction with isocyanates, generates thioalkyl substituted carbodiimides. The reaction of the diaziridinone 80 (R = t-Bu) with triethylphosphite generates an isocyanate and a phosphine imine, which react with each other to give di-t-butylcarbodiimide 81 (90 % yield) and triethylphosphate. " ... 

In the reaction of nitrile oxides with phosphine imines, the five membered ring compounds 142 dissociate already at room temperature to give carbodiimides. For example, reaction of benzonitrile oxide with PhN=P(OEt)3 affords diphenylcarbodiimide in 76 % yield. 

Macromolecules with carbodiimide linkages in their repeat units are obtained from aliphatic and aromatic diisocyanates using a phospholene oxide catalyst. However, instead of linear polymers, only crossUnked thermosets are obtained in this manner. In contrast, linear polymers with pendant carbodiimide units are obtained from poly(vinyl azide) by subsequent reaction with triphenylphosphine to formpoly(phosphine imines) followed by reaction with monoisocyanates to generate the Unear poly(carbodiimides). 

Linear carbodiimides with pendant carbodiimide groups are obtained by reacting polymeric azides derived from vinyl azide 33 with triphenylphosphine to form poly(phosphine imines) 34, which are subsequently converted to polycarbodiimides 35." ... 

The N,0,P phosphine-imine-alcohol donor (122) forms simple square-planar complexes with M ions of the nickel triad. The analogous ether (123) acts as a terdentate ligand to Pd, with CH3 in the fourth site of the square-planar complex. ... 

Interest continues in the area of acyclic phosphazenes which are variously referred to as phosphazo derivatives, phosphine imines or more correctly phosphoranimines. The... 

The phosphonitrilic halides are weaker bases than are some related nonaromatic compounds, just as pyridine is a weaker base than piperidine. The bond type in the phosphonitrilic series is probably the same as in the phosphine-imines RaPrNR (80, 81) the stability of these compounds, too, increases with the electronegativity of the substituents on the phosphorus. Tetraphenylphosphine-imine is one of the most stable of these compounds, and forms a hydrochloride. Its base strength is therefore greater than those of the phosphonitrilic halides, presumably because the opportunities for electronic delocalization are less. The Af-ethyl ester of the trimeric phosphonitrilic acid, which has a cyclic structure, but in which resonance of the same type as in the phosphonitrilic halides cannot occur, also forms a hydrochloride ( 1). It is, therefore, a comparatively strong base, in spite of the inductive effect of the two oxygen atoms on the phosphorus. The extreme weakness of the phosphonitrilic halides as bases cannot therefore be wholly due to the inductive effect of the halogens. 

The phosphides and arsenides of the elements M—PRR and M—AsRR are well known for main group elements, but transition metal analogues are more unusual. Insertion reactions were not widely explored until recently, but examples are given in reactions (j) and (k) (X = O or S) ° and (l) (n) (X = or As ) and (m) are effectively oxidative insertions of a nitrene, or specifically PhN into an Sn-P or Sn-As bond, and thus represent an extension of the Staudinger reactions whereby a phosphine or arsine is treated with an azide, and thereby converted into a phosphine-imine or the arsine analogue, as follows ... 

The reaction of tervalent phosphorus amides containing a NH with activated olefins predictably gives phosphine imines, e.g. (24), through addition and proton transfer. 

Two interesting syntheses of the unstable piperidine alkaloid, nigrifactine (8), have been developed. In one report, " the highly unsaturated ketone (14), prepared by conventional means, was converted into (8) via an unusual reaction which may involve a phosphine-imine intermediate in the other route, elaboration of the side chain (16) - (15) was achieved by a condensation which takes advantage of the acidic methyl protons in (16). 1,4-Dihydro-1-methy 1-4-oxonico-tinonitrile and pelletierine specifically labelled with have been prepared. ... 

Ligands have also been attached to polyethylene glycol so that they can be recovered for recycle by the foregoing methods. A phosphine isocyanate has been reacted with polyethylene glycol for use in the Staudinger reaction with alkyl azides to form a phosphine imine.173 An alkaloid has been attached to the monomethyl ether of polyethylene glycol for use in the Sharpless asymmetrical dihydroxylation of olefins. The reaction was complete in the same time, with no decrease in yield or enantioselectivity, as when the alkaloid was used by itself.174 (Asymmetrical reactions are covered in Chap. 10.)... 

Interest continues to be shown in acyclic phosphazenes (phosphazo derivatives, phosphine imines, phosphoranimines). Reviews include a comprehensive survey of the chemistry (synthesis, structure, bonding and spectroscopy) of transition metal complexes of phosphoranimines, a survey of recent uses of Ph2P(=NSiMe3)NSiMej as a precursor to transition metal... 

---