Organocatalyzed [2+2] Cycloaddition Reactions between Quinone Imine Ketals and Allenoates - Liu, Teng; He, Chixian; Wang, Fan; Shen, Xiang; Li, Yongqin; Lang, Man; Li, Guijun; Huang, Chao; Cheng, Feixiang (Synthesis, 2021)