Conditions for the selective chlorination of α-phosphorylated aldehydes as a means of synthesising α-monochloro- and α,α-dichlorosubstituted derivatives are described. Dichloro derivatives show high reactivity and easily add thiols, amides and ethyleneimine to give stable hemi-thioacetals, hemiamidals and hemiaminal. From the silyl ether of hemiisopropyl thioacetal above 140 o C, an α-ketophosphonate is obtained by the elimination of silane followed by the rearrangement of the oxirane intermediate. Alkylations of α-phosphorylated aldehydes with alkyl bromides gave enol ethers. However, dihalogenoalkanes such as 1,2-dibromoethane or 1,3-dibromopropane yielded phosphatecyclanes along with enol ethers, all in trans configuration.