An efficient method has been developed for the synthesis of a series of(20R)-panaxadiol derivatives(4a–w) using a continuous-flow microreactor.The antitumor activities of the newly synthesized compounds were evaluated in vitro in two human prostate adenocarcinoma tumor cell lines(i.e.,PC-3and LNCa P cells),and their cytotoxicities were evaluated using a standard MTT assay.Compounds 4c,4h,4p,4q and 4s exhibited higher antitumor activities toward PC-3 cell line than panaxadiol,which was used as a reference standard. An efficient method has been developed for the synthesis of a series of (20R) -panaxadiol derivatives (4a-w) using a continuous-flow microreactor. The antitumor activities of the newly synthesized compounds were evaluated in vitro in two human prostate adenocarcinoma tumor cells lines (ie, PC-3 and LNCa P cells), and their cytotoxicities were evaluated using a standard MTT assay. Compounds 4c, 4h, 4p, 4q and 4s exhibited higher antitumor activities toward PC-3 cell line than panaxadiol, which was used as a reference standard.