Synthesis and transformations of new annulated pyranosides using the Pauson-Khand reaction.
The synthesis and transformations of new annulated pyranosides are described. These adducts were prepared by Pauson-Khand reaction on differently functionalized prop-2-ynyl-2,3-dideoxy-alpha-D-erythro-hex-2-enopyranosides (1-8). Compound 1 with a free hydroxyl group at C-4 afforded significant amounts of the hydrogenolysis product 12 in addition to the normal adduct 13. The C-4 O-protected similar precursors (2-8) gave PK products in yields ranging from 39 to 63%. Pauson-Khand adduct 19 provided intermediate 23 after selective manipulation. The oxidation plus decarbonylation synthetic sequence applied to intermediate 23 gave a poor yield of compound 24 using Wilkinson's catalyst. The t-butyl hydroperoxide promoted decarbonylation of product 23 afforded formate 25 in a typical Baeyer-Villiger rearrangement. The Ferrier-II reaction on intermediate 45, readily available from compound 9, afforded the hydrindane-type derivative 46 in 34% yield using a Ferrier-II type reaction.
Marco-Contelles
J
J
Laboratorio de Radicales Libres (CSIC), Instituto de Química Organica General, C/Juan de la Cierva 3, ES-28006 Madrid, Spain. iqoc21@iqog.csic.es
Ruiz-Caro
J
J
D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000138:chemical synthesis*; D002247:Carbon Isotopes; D002625:Chemistry, Organic / Q000379:methods; D019906:Nuclear Magnetic Resonance, Biomolecular; D011714:Pyrans / Q000138:chemical synthesis
D019086:Bridged Bicyclo Compounds, Heterocyclic; D002247:Carbon Isotopes; D011714:Pyrans