Abstract1.3‐dipolar cycloaddition of alkenes (or alkynes) on sugars‐nitriloxides and nitrilimines led respectively to 3‐glycosyl‐isoxazolines (or isoxazoles) and 3‐glycosyl‐pyrazolines (or pyrazoles). 5‐glycosyl‐isoxazolines were similarly prepared from arylnitriloxides and α‐ or ω‐unsaturated sugars. These new C‐glycosides are potential antiviral and anti‐tumor agents.