title: Sulfur-directed enantioselective synthesis of functionalized dihydropyrans.
abstract: The highly selective base-promoted cyclization of enantiopure sulfinyl dienols affords allylic sulfinyl dihydropyrans. The scope of this methodology, including the preparation of seven-membered rings, has been studied in depth. The reactivity of our sulfinyl dihydropyrans toward oxidation, imination, and dihydroxylation has been explored, and thus several routes to densely functionalized pyran derivatives have been outlined. The reactivity of allylic dihydropyranyl sulfones and sulfoximines in S(N)2' processes with organocuprates has been examined. The displacement products were obtained with good regio- and stereoselectivity and fair to good yields. The reactivity of these products to dihydroxylation opens new possibilities to access enantiopure polyhydroxylated tetrahydropyrans that could be of interest for the synthesis of natural products.
authors.affiliation: Instituto de Química Orgánica General, CSIC, Juan de la Cierva, 3, 28006 Madrid, Spain. iqofp19@iqog.csic.es
authors.forename: Roberto
authors.initials: R
authors.lastname: Fernández de la Pradilla
authors.forename: Mariola
authors.initials: M
authors.lastname: Tortosa
authors.forename: Nadia
authors.initials: N
authors.lastname: Lwoff
authors.forename: Miguel A
authors.initials: MA
authors.lastname: del Aguila
authors.forename: Alma
authors.initials: A
authors.lastname: Viso
mesh_terms: D000498:Allyl Compounds / Q000737:chemistry; D003500:Cyclization; D008956:Models, Chemical; D010084:Oxidation-Reduction; D011714:Pyrans / Q000138:chemical synthesis*; D012451:Safrole / Q000031:analogs & derivatives / Q000737:chemistry; D013237:Stereoisomerism; D013450:Sulfones / Q000737:chemistry; D013457:Sulfur Compounds / Q000737:chemistry*
chemical_list: D000498:Allyl Compounds; D011714:Pyrans; D013450:Sulfones; D013457:Sulfur Compounds; D012451:Safrole; C005746:sulfoxide