title: Syntheses of 3,4-benzotropolones by ring-closing metatheses.
abstract: Ortho-lithiated styrenes or ortho-lithiated benzaldehyde dimethyl acetals were added to 2,2-dimethoxypent-4-enals 7. The resulting alcohols were carried on to the aromatic dienones 10. These were ring-closed by olefin metathesis. Hydrolysis of the dimethyl ketal moiety and enolization provided the 3,4-benzotropolones 5. Overall, this access comprises 4-6 steps and totaled a 22-81% yield.
authors.affiliation: Institut für Organische Chemie, Albert-Ludwigs-Universität, Albertstrasse 21, 79104 Freiburg im Breisgau, Germany.
authors.forename: Deniz
authors.initials: D
authors.lastname: Arican
authors.forename: Reinhard
authors.initials: R
authors.lastname: Brückner
mesh_terms: D000438:Alcohols / Q000737:chemistry*; D000475:Alkenes / Q000737:chemistry*; D044946:Biflavonoids / Q000138:chemical synthesis* / Q000737:chemistry*; D002392:Catechin / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry; D015394:Molecular Structure; D013237:Stereoisomerism
chemical_list: D000438:Alcohols; D000475:Alkenes; D044946:Biflavonoids; C508389:benzotropolone; D002392:Catechin