Acylation of N‐silylated and 2,3‐substituted 1,2‐thiazetidine 1,1‐dioxides (β‐sultams) results in the formation of 4‐acylated β‐sultams 2 and 8. The desilylation of 2 to 3 is easily done with TBAF either on silica gel or in ethanolic solution. The acylated β‐sultams are reduced by sodium borohydride yielding α‐hydroxyalkyl β‐sultams 11 and 12, obtained as mixtures of diastereoisomers. These are separated by CC. The stereochemistry of the acylated and of the α‐hydroxylated β‐sultams is elucidated by spectroscopic methods, and compared to that of the antibiotic drug thienamycin.