The syntheses of racemic and optically active pseudodeflectusin and ustusorane C are described. The (1)H- and (13)C-NMR data for our synthetic pseudodeflectusin and ustusorane C were identical to those of the corresponding natural products. We also synthesized the proposed structure of aspergione A and B whose (1)H- and (13)C-NMR data were identical to those of ustusorane C and pseudodeflectusin. The (1)H- and (13)C-NMR spectra of our synthetic aspergione A and B were different from those of the natural compounds. Our results confirm that aspergione A and B are in fact ustusorane C and pseudodeflectusin, respectively.