Organocatalytic Enantioselective Hydroxymethylation of Oxindoles with Paraformaldehyde as C1 Unit（J. Org. Chem. 2010, 75, 4872–4875） Graphic AbstractABSTRACTA bifunctional thiourea-tertiary amine-catalyzed asymmetric hydroxymethylation of 3-substituted oxindoles using paraformaldehyde as C1 unit was developed. A wide scope of oxindoles, bearing C3 sterically congested quaternary carbon centers, were smoothly obtained in good to excellent yields (up to 99%) and high enantioselectivities (up to 91% ee) under mild reaction conditions. More significant feature of this approach is employing cheap and readily available paraformaldehyde as ahydroxymethylation C1 unit, which activated by chiral bifunctional thiourea organocatalysts.