Some reactions of tetraphenyldiphosphine.

Both the methods of preparation, and the reactions, of diphosphines are reviewed briefly. Both the photolytic and thermal reactions of tetraphenyl-diphosphine with alcohols have been studied. The reaction probably proceeds via a combination of ionic and free radical mechanisms. The mechanistic postulations are supported by the results of the reaction of tetraphenyldiphosphine with ditertiarybutyl peroxide. The reactions of tetraphenyldiphosphine with both aromatic and aliphatic carboxylic acids have been studied. The results have been rationalized into a general mechanism which involves the rearrangement of an alpha-hydroxy phosphine oxide to a phosphinate. This type of rearrangement may be extended to include all a-hydroxy phosphine oxides which contain a group capable of stabilising a carbanion in the alpha-position to both the phosphine oxide and the hydroxyl group. The reactions of tetraphenyldiphosphine with aldehydes have been studied briefly and a mechanism has been postulated to account for the products which are formed.