The anomeric d-fructopyranosyl and l-sorbopyranosyl cyanides have been prepared via reaction of the respective 2- O-acetyl-1,3,4,5-tetra- O-benzoyl derivatives with BF 3-trimethylsilyl cyanide in nitromethane. Configurations of the products at the tertiary center were assigned on the basis of rotational comparisons, 1H NMR data, and, in the case of β- d-fructosyl cyanide, by an X-ray structural analysis. From the conformational preferences of the 2-epimers — the cyano group invariably adopts an axial disposition entailing the 5 C 2 conformation for the β- d- fructo and α- l- sorbo cyanides versus the alternative 2 C 5 form for the α- d- fructo and β- l- sorbo anomers — the anomeric effect of a cyano group may be assessed to be of the same order of magnitude as that exerted by an acyloxy function.