title: Polymer-supported palladacycles: efficient reagents for synthesis of benzopyrans with palladium recovery. Relationship among resin loading, Pd:P ratio, and reactivity of immobilized palladacycles.
abstract: [reaction: see text] Oxapalladacycles were immobilized on polystyrene-divinylbenzene supports and treated with 3-aryl-2-propynoates or 1-alkyl-1,2-propadienes to afford 2H-1-benzopyrans in yields superior to those for solution-phase experiments. Isolation of benzopyrans was facilitated, and 71-80% of the palladium was recovered. Effects of resin loading with phosphorus and palladium were studied, and the optimum immobilized palladacycles featuring a medium loading with P (1.35 mmol P/g) and a high loading with Pd (Pd:P ratio 1:1.7) were identified. Resins with higher swelling capacities were more reactive.
authors.affiliation: Department of Chemistry, University of Kansas, 1251 Wescoe Hall Drive, Lawrence, Kansas 66045-7582, USA.
authors.forename: John C
authors.initials: JC
authors.lastname: Hershberger
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.forename: Genliang
authors.initials: G
authors.lastname: Lu
authors.forename: Helena C
authors.initials: HC
authors.lastname: Malinakova
mesh_terms: D001578:Benzopyrans / Q000737:chemistry*; D003500:Cyclization; D015394:Molecular Structure; D010165:Palladium / Q000737:chemistry*
chemical_list: D001578:Benzopyrans; D010165:Palladium