Jianguang Han, Xia Li, Yong Guan, Wenjun Zhao, William D. Wulff * and Xiaoguang Lei*
Angew. Chem. Int. Ed. 2014, 53, 9257-9261
The first enantioselective total syntheses of prenylflavonoid Diels-Alder natural products (-)-kuwanon I, (+)-kuwanon J, (-)-brosimone A and (-)-brosimone B have been accomplished based on a concise synthetic strategy. Key elements of the synthesis include a biosynthesis-inspired asymmetric Diels-Alder cycloaddition mediated by a chiral VANOL-boron Lewis acid, as well as a process involving regioselective Schenck ene […]
The first enantioselective total syntheses of prenylflavonoid Diels-Alder natural products (-)-kuwanon I, (+)-kuwanon J, (-)-brosimone A and (-)-brosimone B have been accomplished based on a concise synthetic strategy. Key elements of the synthesis include a biosynthesis-inspired asymmetric Diels-Alder cycloaddition mediated by a chiral VANOL-boron Lewis acid, as well as a process involving regioselective Schenck ene reaction, reduction and dehydration to realize a biomimetic dehydrogenation for generation of the required diene precursor. Furthermore, a remarkable tandem inter-/intramolecular asymmetric Diels-Alder cycloaddition process was applied for the synthesis of brosimone A.
http://onlinelibrary.wiley.com/doi/10.1002/anie.201404499/abstract