title: Enantioselective syntheses of carbanucleosides from the Pauson-Khand adduct of trimethylsilylacetylene and norbornadiene.
abstract: A new enantioselective approach to carbanucleosides from Pauson-Khand (PK) adduct 1 is disclosed. The chiral cyclopentenone 1 is readily accessible in enantiomerically pure form via PK reaction of trimethylsilylacetylene and norbornadiene using N-benzyl-N-diphenylphosphino-tert-butyl-sulfinamide as a chiral P,S ligand. (-)-Carbavir and (-)-Abacavir were enantioselectively synthesized starting from (-)-1. The key steps of the sequence are a photochemical conjugate addition of a hydroxymethyl radical, a retro-Diels-Alder reaction, and a palladium catalyzed allylic substitution to introduce the nucleobase.
authors.affiliation: Unitat de Recerca en Síntesi Asimètrica (URSA-PCB), Institute for Research in Biomedicine and Departament de Química Orgànica, Universitat de Barcelona, Parc Científic de Barcelona c/ Baldiri Reixac 10, 08028 Barcelona, Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: Vázquez-Romero
authors.forename: Julia
authors.initials: J
authors.lastname: Rodríguez
authors.forename: Agustí
authors.initials: A
authors.lastname: Lledó
authors.forename: Xavier
authors.initials: X
authors.lastname: Verdaguer
authors.forename: Antoni
authors.initials: A
authors.lastname: Riera
mesh_terms: D003486:Cyanides / Q000737:chemistry; D003517:Cyclopentanes / Q000737:chemistry; D006900:Hydroxylation; D008745:Methylation; D015394:Molecular Structure; D009705:Nucleosides / Q000138:chemical synthesis* / Q000737:chemistry; D010777:Photochemistry; D013237:Stereoisomerism
chemical_list: D003486:Cyanides; D003517:Cyclopentanes; D009705:Nucleosides; C007201:cyclopentanone