title: Unprecedented 8,9'-neolignans: enantioselective synthesis of possible stereoisomers for structural determination.
abstract: (+)-Wutaienin (3) and its C-7 methyl ether (4), isolated from Zanthoxylum wutaiense, were found to be unprecedented 8,9'-neolignans containing an (S)-2-(1,1-dimethyl-1-hydroxymethyl)-7-methoxydihydrobenzofuran skeleton. Wutaienin (3) was present in the plant as an inseparable 1:1 mixture of the (7,8)-syn-diastereoisomers. The diastereoisomeric mixture was characterized by comparison with four possible diastereoisomers, which were enantioselectively synthesized from (S)-5-bromo-(1,1-dimethyl-1-hydroxymethyl)-7-methoxydihydrobenzofuran using Evans' oxazolidinone-assisted asymmetric aldol condensation to install the chiral centers at the C-7 and C-8 positions.
authors.affiliation: Graduate School of Pharmaceutical Sciences, Chiba University , 1-8-1 Inohana, Chuo, Chiba 260-8675, Japan.
authors.forename: Masato
authors.initials: M
authors.lastname: Takahashi
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Suzuki
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Ishikawa
authors.forename: Hung-Yi
authors.initials: HY
authors.lastname: Huang
authors.forename: Hsun-Shuo
authors.initials: HS
authors.lastname: Chang
authors.forename: Ih-Sheng
authors.initials: IS
authors.lastname: Chen
mesh_terms: D017705:Lignans / Q000737:chemistry* / Q000302:isolation & purification*; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D023303:Oxazolidinones / Q000737:chemistry; D013237:Stereoisomerism; D032106:Zanthoxylum / Q000737:chemistry*
chemical_list: D017705:Lignans; D023303:Oxazolidinones; C000595472:wutaienin; C000595473:wutaienin C-7 methyl ether