title: Modified chiral triazolium salts for enantioselective benzoin cyclization of enolizable keto-aldehydes: synthesis of (+)-sappanone B.
abstract: Asymmetric synthesis of (+)-sappanone B (1), a natural product with a 3-hydroxy chromanone structure, was achieved via enantioselective benzoin cyclization by using a modified Rovis catalyst and triethylamine. This catalyst enabled the successful benzoin cyclization of readily enolizable keto-aldehydes.
authors.affiliation: Department of Chemistry, Tokyo Institute of Technology, SORST-JST Agency, 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8551, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Takikawa
authors.forename: Keisuke
authors.initials: K
authors.lastname: Suzuki
mesh_terms: D000447:Aldehydes / Q000138:chemical synthesis* / Q000737:chemistry; D001573:Benzoin / Q000138:chemical synthesis* / Q000737:chemistry; D029911:Caesalpinia / Q000737:chemistry; D002384:Catalysis; D018360:Crystallography, X-Ray; D003500:Cyclization; D004224:Diterpenes / Q000138:chemical synthesis*; D005021:Ethylamines / Q000737:chemistry; D008968:Molecular Conformation; D013237:Stereoisomerism; D014230:Triazoles / Q000737:chemistry*
chemical_list: D000447:Aldehydes; D004224:Diterpenes; D005021:Ethylamines; D014230:Triazoles; C522057:abrotanone; D001573:Benzoin; C016162:triethylamine