Prolinamide/PPTS-Catalyzed Hajos-Parrish Annulation: Efficient Approach to the Tricyclic Core of Cylindricine-Type Alkaloids - Zhang, Xiao-Ming; Wang, Min; Tu, Yong-Qiang; Fan, Chun-An; Jiang, Yi-Jun; Zhang, Shu-Yu; Zhang, Fu-Min (Synlett, 2008)