add thiols, amides and ethyleneimine to givestable hemi-thioacetals, hemiamidals and hemiaminal. From the silylether of hemiisopropyl thioacetal above 140°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