title: RCM for the construction of novel steroid-like polycyclic systems. 1. Studies on the synthesis of a PreD3-D3 transition state analogue.
abstract: Natural and nonnatural polycyclic systems containing eight-membered carbocycles constitute a large class of compounds of importance in organic chemistry, biology, and medicine. Here we describe a new strategy by which complex polycyclic steroid-like systems can be constructed on the steroid CD framework, by a combination of RCM and Heck cyclizations. The method is exemplified by its application to the stereoselective synthesis of 6-8-6 fused carbocyclic systems that mimic the putative transition structure of the isomerization of previtamin D3 to vitamin D3.
authors.affiliation: Departamento de Química Orgánica e Unidade Asociada ó C.S.I.C., Facultade de Química, Universidade de Santiago, 15782 Santiago de Compostela, Spain.
authors.forename: Rebeca
authors.initials: R
authors.lastname: García-Fandiño
authors.forename: María José
authors.initials: MJ
authors.lastname: Aldegunde
authors.forename: Eva M
authors.initials: EM
authors.lastname: Codesido
authors.forename: Luis
authors.initials: L
authors.lastname: Castedo
authors.forename: Juan R
authors.initials: JR
authors.lastname: Granja
mesh_terms: D002762:Cholecalciferol / Q000031:analogs & derivatives* / Q000138:chemical synthesis* / Q000737:chemistry; D003500:Cyclization; D015394:Molecular Structure; D011084:Polycyclic Aromatic Hydrocarbons / Q000737:chemistry*; D013237:Stereoisomerism; D013256:Steroids / Q000737:chemistry*
chemical_list: D011084:Polycyclic Aromatic Hydrocarbons; D013256:Steroids; D002762:Cholecalciferol; C025168:previtamin D(3)