[5C + 1C/N/S/Se] Annulations of α-Alkenoyl-α-carbamoylketene Dithioacetals: A Facile and Convenient Synthesis of Salicylamide, Nicotinamide and Thio/Selenopyran-3-carboxamide Derivatives - Li, Dongwei; Xu, Xianxiu; Liu, Qun; Dong, Song (Synthesis, 2008)