lkylamino)phosphine and a halogen compound represented by Formula VIII:wherein X is as defined above.The above reaction can also be carried out in an inert solvent in the presence of metallic zinc, if necessary.Examples of the inert solvent used include hydrocarbons such as benzene, xylene, toluene, etc.; ethers such as diethyl ether, diisopropyl ether, tetrahydrofuran, dioxane, etc.; hydrocarbon