Dicoordinated phosphorus compounds, synthesis

Synthesis of New Dicoordinated Phosphorus Compounds with a P(III)=N Bond... 

These compounds react with the amines to give the corresponding dicoordinated phosphorus compounds, a number of which may remain in the free state for a few hours before once again oligomerizing Particular notice should be given to the synthesis of the diaza-phospholes... 

In the synthesis of specially substituted methylene diphosphines, made from secondary phosphines and carbonyl derivatives (7), a carbenium ion adjacent to trivalent phosphorus as the transition state has been discussed. The transfer of this reaction principle to primary phosphines and suitable carbonyl compound revealed a further pathway to derivatives of dicoordinated phosphorus (8). Aromatic phosphines react with carboxylic acid amide acetals under elimination of alcohol giving dialkylamino-alkylidene phosphines (Scheme 5). A modification of the synthesis... 

A further method for the synthesis of cyclic compounds in the phosphinic acid series, and investigated within the last decade, is the clearly not unrelated cheletropic reaction which takes place between alka-1,3-dienes and phosphenium salts. The latter are based on dicoordinate phosphorus, [R R P ], the commonly encountered counter ion being the tetrachloroaluminate anion. Such salts are obtained in situ through the interaction of AICI3 and a hosphorus(III) chloride R R PCl, for which R = Cl, R = R2N, or R = R =... 

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