title: Versatile use of hindered oxalates for the stereoselective preparation of novel 11-modified androst-5-ene derivatives.
abstract: The 11alpha- and 11beta-modified androst-5-ene derivatives 3a,b as well as the exo- and endocyclic dehydrated compounds 4a-c and 5b-c were produced using the oxalate derivatives of the highly hindered 11beta-hydroxyandrost-5-enes 1a-c. The 11-tetrahydrofuran derivative 6 was produced for the first time with good diastereoselectivity by an intramolecular 5-exo cyclization under radical conditions from the corresponding oxalate as precursor.
authors.affiliation: Laboratoire de Chimie et Biochimie des Complexes Moléculaires, Ecole Nationale Supérieure de Chimie et CNRS, 11 rue Pierre et Marie Curie, 75005 Paris, France.
authors.forename: Vincent
authors.initials: V
authors.lastname: Lecomte
authors.forename: Elie
authors.initials: E
authors.lastname: Stéphan
authors.forename: Marie-Noelle
authors.initials: MN
authors.lastname: Rager
authors.forename: Gérard
authors.initials: G
authors.lastname: Jaouen
mesh_terms: D000736:Androstenes / Q000138:chemical synthesis*; D000737:Androstenols / Q000737:chemistry; D003500:Cyclization; D005609:Free Radicals / Q000737:chemistry; D005663:Furans / Q000737:chemistry; D015394:Molecular Structure; D010070:Oxalates / Q000737:chemistry*; D010084:Oxidation-Reduction; D013237:Stereoisomerism
chemical_list: D000736:Androstenes; D000737:Androstenols; D005609:Free Radicals; D005663:Furans; D010070:Oxalates