N-Benzyl-2,3-O-isopropylidene-d-glyceraldehyde nitrone (1; Scheme [¹] ) is a highly flexible compound that can be used as reagent in a number of addition reactions, [3+2] cycloadditions, and the new [3+3] cyclization leading to chiral nitrogen-containing acyclic and cyclic products. The enantiopure nitrone can be prepared by a very effective route from the readily available d-mannitol. Starting with a regioselective ketalization, oxidative diol cleavage of the resulting glycol results in the d-glyceraldehyde precursor. [¹] Treatment of this aldehyde with N-benzylhydroxylamine in the presence of MgSO4 gives nitrone 1 in excellent yield. [²]