A direct catalytic stereoselective synthesis of C4’ functionalized furanoside and nucleoside derivatives with a tetrasubstituted stereocenter is disclosed. The amine-catalyzed stereoselective α-aminomethylation reactions on furanoside-derived aldehyde derivatives gave the corresponding C4’ functionalized D- or L-ribose derivatives in good to excellent yields (67⁻94%) with up to >20:1 dr.