title: Enantioselective biomimetic total syntheses of kuwanons I and J and brosimones A and B.
abstract: The first enantioselective total syntheses of prenylflavonoid Diels-Alder natural products (-)-kuwanon I, (+)-kuwanon J, (-)-brosimone A, and (-)-brosimone B have been accomplished from a common intermediate based on a concise synthetic strategy. Key elements of the synthesis include a biosynthesis-inspired asymmetric Diels-Alder cycloaddition mediated by a chiral ligand/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.
authors.affiliation: School of Pharmaceutical Science and Technology, Tianjin University, Tianjin 300072 (China).
authors.forename: Jianguang
authors.initials: J
authors.lastname: Han
authors.forename: Xia
authors.initials: X
authors.lastname: Li
authors.forename: Yong
authors.initials: Y
authors.lastname: Guan
authors.forename: Wenjun
authors.initials: W
authors.lastname: Zhao
authors.forename: William D
authors.initials: WD
authors.lastname: Wulff
authors.forename: Xiaoguang
authors.initials: X
authors.lastname: Lei
mesh_terms: D040761:Biomimetic Materials / Q000737:chemistry*; D047188:Chalcones / Q000138:chemical synthesis* / Q000737:chemistry; D005419:Flavonoids / Q000138:chemical synthesis* / Q000737:chemistry*; D008968:Molecular Conformation; D013237:Stereoisomerism
chemical_list: D047188:Chalcones; D005419:Flavonoids; C412060:brosimine B; C000598004:brosimonn A; C000598003:kuwanon I; C574108:kuwanon J 2,4,10''-trimethyl ether
keywords: boron; cyclization; natural products; synthetic methods; total synthesis