Acylation of steroidal saturated ketones and their enol acetates with acetic anhydride and BF3-etherate has been studied. α-Acylketones were obtained from 3-keto, 7-keto and 16-keto steroids (I, XII and IX) in the A/B trans series and from 3-ketone (VI) in the A/B cis series. The intermediate difluoroboron chelates (II and VII) were isolated and characterized. No C-acylation of tertiary carbon atom