Phosphine-Catalyzed[3+2] Annulations with γ-Methyl Allenoates
Ma Rong, Song Gege, Xi Qiuzhen, Yang Liu, Li Er-Qing, Duan Zheng
Chin. J. Org. Chem. . 2019, (8): 2196 -2202 .  DOI: 10.6023/cjoc201901040