Novel preparation of ion-supported triphenylphosphines and their synthetic utility

Novel ion-supported Ph3P compounds, 4-(diphenylphosphino)- benzyltrimethylammonium bromide (A) and N-methyl-N-[4-(diphenylphosphino) -benzyl]pyrrolidinium bromide (B), were prepared. Because of their stability in air, ion-supported Ph3P A and B could be used for the halogenation of alcohols, the esterification of carboxylic acid with the Mitsunobu reaction, the Mizoroki–Heck reaction, and the Sonogashira reaction. The advantages of using these ion-supported Ph3P A and B are the simple isolation of the products by ether extraction due to their poor solubility in ether, and the easy recovery of the co-product, ion-supported Ph3PO, by filtration in high yields (>90%), which could be regenerated and reused for the same reactions, in the halogenation of alcohols and the esterification of carboxylic acid with the Mitsunobu reaction. On the other hand, ionic liquid reaction media containing Pd(OAc)2 or PdCl2 and ion-supported Ph3P A or B as catalysts could be reused for the same Mizoroki–Heck reaction and the Sonogashira reaction maintaining high yields, using iodotoluene with methyl acrylate and phenylacetylene, respectively.