title: Palladium-catalyzed synthesis of 4-oxaspiro[2.4]heptanes via central attack of oxygen nucleophiles to π-allylpalladium intermediates.
abstract: A palladium-catalyzed decarboxylative cyclopropanation of γ-methylidene-δ-valerolactones with aromatic aldehydes has been developed to give 4-oxaspiro[2.4]heptanes with high selectivity. The site of nucleophilic attack to a π-allylpalladium intermediate has been controlled with a sterically demanding phosphine ligand. The course of the reaction is highly dependent on ligands and solvents, and selective formation of methylenetetrahydropyrans has also been realized.
authors.affiliation: Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo, Kyoto 606-8502, Japan. shintani@kuchem.kyoto-u.ac.jp
authors.forename: Ryo
authors.initials: R
authors.lastname: Shintani
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Ito
authors.forename: Tamio
authors.initials: T
authors.lastname: Hayashi
mesh_terms: D002384:Catalysis; D003521:Cyclopropanes / Q000737:chemistry; D006536:Heptanes / Q000138:chemical synthesis* / Q000737:chemistry; D008024:Ligands; D015394:Molecular Structure; D010100:Oxygen / Q000737:chemistry*; D010165:Palladium / Q000737:chemistry*; D010720:Phosphines / Q000737:chemistry; D011753:Pyrones / Q000737:chemistry; D013141:Spiro Compounds / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D003521:Cyclopropanes; D006536:Heptanes; D008024:Ligands; D010720:Phosphines; D011753:Pyrones; D013141:Spiro Compounds; C052207:delta-valerolactone; D010165:Palladium; C044646:phosphine; D010100:Oxygen