Novel bicyclic iminosugar derivatives fused thiazolidin-4-one were conveniently synthesized by double Pummerer rearrangements, and their HIV reverse transcriptase (RT) inhibitory activities were preliminary examined. The notable anti-HIV-RT activity demonstrated that such bicyclic azasugars hold potential as a new kind of HIV-RT inhibitors. (C) 2012 Elsevier Ltd. All rights reserved.