General Procedure E. To a solution of a chalcone derivative in pyridine (16 mL/mmol) was added Hg(OAc)2 (1 equiv). The solution was refluxed for 15 h. After cooling, iced water was added and the mixture was extracted three times with AcOEt. The combined organic layers were washed with water and brine, dried over anhydrous MgSO4, filtered, and the filtrate was concentrated under reduced pressure to afford the crude product.