A Facile Synthesis of the Angucyclinone Antibiotic (+)-Rubiginone B2 Involving the BF3-Mediated Diels-Alder Reaction of Juglone - Motoyoshiya, Jiro; Masue, Yusuke; Iwayama, Gento; Yoshioka, Sachiko; Nishii, Yoshinori; Aoyama, Hiromu (Synthesis, 2004)