title: Stereoselective convergent synthesis of 24,25-dihydroxyvitamin D3 metabolites: a practical approach.
abstract: Vitamin D3 active metabolites 24R,25-(OH)2-D3, 24S,25-(OH)2-D3, and 1 alpha, 24R,25-(OH)3-D3 were synthesized by a convergent and stereoselective approach. In the synthetic route, the stereogenic center at C-24 was generated through ultrasonically induced aqueous conjugate addition of iodide 6 to Seebach's dioxolanone 5, and the vitamin D triene system was constructed using the Lythgoe approach. The synthesis, which is both short (seven steps from iodide 6) and efficient (32-40% overall yield), allows the preparation of large quantities of the metabolites and provides a novel example of a highly stereoselective reaction promoted by the zinc-copper couple in aqueous media.
authors.affiliation: Departamento de Química Fundamental Universidade da Coruña, 15071 A Coruña, Spain.
authors.forename: José
authors.initials: J
authors.lastname: Pérez Sestelo
authors.forename: Iván
authors.initials: I
authors.lastname: Cornella
authors.forename: Olga
authors.initials: O
authors.lastname: de Uña
authors.forename: Antonio
authors.initials: A
authors.lastname: Mouriño
authors.forename: Luis A
authors.initials: LA
authors.lastname: Sarandeses
mesh_terms: D015650:24,25-Dihydroxyvitamin D 3 / Q000031:analogs & derivatives / Q000138:chemical synthesis* / Q000737:chemistry / Q000378:metabolism*; D008968:Molecular Conformation; D015394:Molecular Structure; D013237:Stereoisomerism
chemical_list: D015650:24,25-Dihydroxyvitamin D 3