Phosphinimines intermediates

The reaction of triphenylphosphine with A -arylsulphonylsulphimides in DMF gives a sulphide and a phosphinimine via a 1,3-dipolar sulphurane intermediate (91). ... 

When the W-trimethylsilyltris(2-pyridyl)phosphinimine (22) was treated with one equivalent of methyllithium at - 78°C, a lithium complex (23) binding a dipyridyl moiety with a trivalent amino-methyl (2-pyridyl)phosphane was isolated. This compound results from a ligand coupling process taking place on the pentacoordinate phosphorus intermediate formed by addition of methyllithium on the imine bond. 

Recent advances in the Staudinger reaction of tertiary phosphines with azido compounds have been reviewed.The reaction of the alkynylphosphine (88) with phenylazide yields the unstable intermediate (89), which in the presence of protic substances undergoes nucleophilic addition to the triple bond. The reactivity of the nitrogen-silicon bond of the phosphinimine derived from triphenylphosphine and trimethylsilylazide has been exploited in reactions with chloroformyl reagents to generate new functionalised phosphinimines, e.g., (90). ... 

Phosphinimines obtained from 1,2-trans 6-0-/ -tolylsulfonylhexopyranosyl azides rearrange to 6-amino-l,6-anhydro-6-deoxyhexoses, which are stable as acylated derivatives. As intermediates, the tosylate salts could be... 

Azides may be reduced to amines with triphenylphosphine in what is known as the Staudinger reaction. The probable mechanism involves attack of triphenylphosphine on the azide and formation of a phosphinimine via a four-membered intermediate—notice the similarity with the Wittig reaction ... 

Tetra-O -acetyl-B-D-gluco- and -galacto-pyranosylamines (1) have been obtained from the corresponding glycosyl azides (2) by Staudinger reaction followed by hydrolysis of the intermediate phosphinimines (3) alternative reactions of intermediates (3) with carbon dioxide yielded the 1,2-trans-carbamates ( )... 

One variety of phosphinimines, the N-aryl trichlorophosphine imines, Cl3P=NR, are produced in good yield when phosphorus pentachloride reacts with an equimolecular quantity of a primary aromatic amine in boiling tetrachloromethane. The intermediate monophosphazene is usually too unstable for isolation, although fiuoro analogues can be made. 

Scheme 2.3 Oxidative resolution of phosphines using intermediate phosphinimines.

The intermediate phosphonium thiocyanate (2) gives phosphinimines with an excess of amine, and acylthioureas and amides when treated with carboxylic acids. A Beckmann rearrangement of amidoximes RCCNOHlNHj with PhSOjCI in pyridine, followed by treatment with HjS, gives thioureas RNHCSNHj in 55—76% yields. ... 

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