Ynamide Protonation-Initiated Cis-Selective Polyene Cyclization and Reaction Mechanism.  Jiasheng Yao†, Chen-Long Li†, Xing Fan, Zhou Wang, Zhi-Xiang Yu* & Junfeng Zhao*, CCS Chemistry 2021, 3, 3133-3143. (†Jiasheng Yao and Chen-Long Li contributed equally)