Three pairs of novel 2-aryl-3,4,5-trihydroxypiperidines (6-8 and their enantiomers), the piperidine analogues of the pyrrolidine alkaloids radicamine A and radicamine B, were prepared from six-membered cyclic nitrones through a concise two-step procedure, i.e., Grignard reagent addition and deprotection. These novel polyhydroxylated piperidine iminosugars were assayed against 10 types of enzymes. Only compound 8 exhibited weak inhibition (IC50 1080 mu mol/L) against beta-galactosidase from rat intestinal lactases. (C) 2013 Atsushi Kato and Chu-Yi Yu. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.