title: Enantioselective total synthesis of the natural gamma-tocopherol metabolite (S)-gamma-CEHC [(S)-LLU-alpha].
abstract: The asymmetric synthesis of the natural gamma-tocopherol metabolite (S)-gamma-CEHC (1) is described in 10 steps and 18.4% overall yield starting from 2,3-dimethylhydroquinone. The key step is a stereoselective TiCl(4)-mediated homochiral sulfoxide-directed allylation of ketal (SS)-3 to efficiently generate the challenging C-2 stereogenic carbon of chroman (SS,S)-2 with the correct absolute configuration.
authors.affiliation: Departamento de Química Orgánica (Módulo 01), Universidad Autónoma de Madrid, c/Francisco Tomas y Valiente 7, Cantoblanco, 28049-Madrid, Spain.
authors.forename: Mercedes
authors.initials: M
authors.lastname: Lecea
authors.forename: Gloria
authors.initials: G
authors.lastname: Hernández-Torres
authors.forename: Antonio
authors.initials: A
authors.lastname: Urbano
authors.forename: M Carmen
authors.initials: MC
authors.lastname: Carreño
authors.forename: Françoise
authors.initials: F
authors.lastname: Colobert
mesh_terms: D000818:Animals; D002384:Catalysis; D002839:Chromans / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure; D011422:Propionates / Q000138:chemical synthesis* / Q000737:chemistry; D051381:Rats; D013237:Stereoisomerism; D024504:gamma-Tocopherol / Q000378:metabolism*
chemical_list: D002839:Chromans; D011422:Propionates; C107690:2,7,8-trimethyl-2-(beta-carboxyethyl)-6-hydroxychroman; D024504:gamma-Tocopherol