title: Stereoselective synthesis by olefin metathesis and characterization of η-carotene (7,8,7',8'-tetrahydro-β,β-carotene).
abstract: The purported structure of the elusive η-carotene (7,8,7',8'-tetrahydro-β,β-carotene), a natural C(40) carotenoid first detected in the berries of Lonicera japonica and in citrus fruits sixty years ago, has been synthesized by olefin cross-metathesis/dimerization of a C(21) polyene derived from trans-7,8-dihydroretinal, thus allowing the full characterization of this highly unstable natural product.
authors.affiliation: Departamento de Química Orgánica, Facultade de Química,  Universidade de Vigo , 36310 Vigo, Spain.
authors.forename: Noelia
authors.initials: N
authors.lastname: Fontán
authors.forename: Rosana
authors.initials: R
authors.lastname: Alvarez
authors.forename: Angel R
authors.initials: AR
authors.lastname: de Lera
mesh_terms: D000475:Alkenes / Q000737:chemistry*; D002338:Carotenoids / Q000138:chemical synthesis* / Q000737:chemistry*; D002957:Citrus / Q000737:chemistry; D005638:Fruit / Q000737:chemistry; D031239:Lonicera / Q000737:chemistry*; D015394:Molecular Structure; D013237:Stereoisomerism
chemical_list: D000475:Alkenes; C573868:nu-carotene; D002338:Carotenoids