Sugar1,2-orthoesters are one of the most important intermediates in the organic synthesis and natural product synthesis ,[1,2] especially in the oligosaccharide synthesis .[3-5] Orthoesters typically undergo rearrangement by the action of protonic or Lewis acids ,resulting in the formation of glycosidic products .[6] These methods for the synthesis of sugar 1,2-sugar orthoesters involve the treatment of peracetylated glycosyl bromides with alcohols in the presence of a quaternary ammonium salt and 2,6-lutidine et al[7,8] Although the methods have been extensively used ,there is still a large disadvantage , the use of an organic base which is smelly ,toxic and eco-unfriendly . Herein in a facile and efficient method for synthesis of 1,2-orthoesters promoted by potassium fluoride instead of organic base was reported . Our goal is to establish the feasibility of this reaction as a general method for the synthesis of 1,2-orthoesters,[9] even sugar-sugar orthoesters . Various sugar orthoesters were prepared in good yield .