There is provided a process for the selective anomeric deacetylation of sugar derivatives, which may be substituted by substituents such as acetoxy, chloracetoxy, alkoxy, azido, etc., by means of tin compounds R.sub.3 SnOR' or R.sub.2 SnO where R is lower alkyl resulting either directly in the desired anomeric compound or in an intermediate which is converted to the desired compound by silica or by acid hydrolysis.