title: Cross-coupling reactions of organosilicon compounds in the stereocontrolled synthesis of retinoids.
abstract: This paper presents a full account of the use of Hiyama cross-coupling reactions in a highly convergent approach to retinoids in which the key step is construction of the central C10-C11 bond. Representatives of two families of oxygen-activated dienyl silanes (ethoxysilanes and silanols) and of all reported families of "safety-catch" silanols (siletanes, silyl hydrides, allyl-, benzyl-, aryl-, 2-pyridyl- and 2-thienylsilanes) were regio- and stereoselectively prepared and stereospecifically coupled to an appropriate electrophile by treatment with a palladium catalyst and a nucleophilic activator. Both all-trans and 11-cis-retinoids, and their chain-demethylated analogues, were obtained in good yields regardless of the geometry (E/Z) and of the steric congestion in each fragment. This comprehensive study conclusively establishes the Hiyama cross-coupling reaction, with its mild reaction conditions and stable, easily prepared, ecologically advantageous silicon-based coupling partners, as the most effective route to retinoids reported to date.
authors.affiliation: Departamento de Química Orgánica, Facultad de Química, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain.
authors.forename: Julián
authors.initials: J
authors.lastname: Bergueiro
authors.forename: Javier
authors.initials: J
authors.lastname: Montenegro
authors.forename: Fermín
authors.initials: F
authors.lastname: Cambeiro
authors.forename: Carlos
authors.initials: C
authors.lastname: Saá
authors.forename: Susana
authors.initials: S
authors.lastname: López
mesh_terms: D002384:Catalysis; D003432:Cross-Linking Reagents / Q000737:chemistry*; D015394:Molecular Structure; D017646:Organosilicon Compounds / Q000737:chemistry*; D012176:Retinoids / Q000138:chemical synthesis* / Q000737:chemistry*; D012821:Silanes / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D003432:Cross-Linking Reagents; D017646:Organosilicon Compounds; D012176:Retinoids; D012821:Silanes; C082343:silanol