Keywords: Multicomponent reactions / Diastereoselectivity / Indium(III) chloride / Imines / Nitrogen heterocycles A library of polyhydroxylated pyrrolidines was obtained by performing a tandem Staudinger/aza-Wittig/Ugi three-component reaction on a L-ribose-derived 4-azido aldehyde. In this paper we describe the effect of Lewis acids on the diastereoselectivity of the final Ugi three-component reaction step that the intermediate (D-lyxo-pyrroline) cyclic imine undergoes. When the Ugi reaction was performed in methanol almost exclusively pyrrolidines with a 2,3-cis relationship