title: Pd(II)-catalyzed cascade Wacker-Heck reaction: chemoselective coupling of two electron-deficient reactants.
abstract: A novel palladium(II)-catalyzed oxy-carbopalladation process was developed allowing for the orchestrated union of hydroxy ynones with ethyl acrylate, two electron-deficient reactants. With beta-hydroxy ynones, this cascade Wacker-Heck process gave access to highly functionalized tri- or tetrasubstituted dihydropyranones featuring an unusual dienic system. For diastereomerically pure and for enantioenriched beta-hydroxyynones, these reactions proceed without affecting the stereochemical integrity of the existing stereocenters. In addition, tetrasubstituted furanones can be prepared when alpha-hydroxyynones and ethyl acrylate are used as starting materials. The dihydropyranones and furanones obtained upon cyclization are novel compounds, but structurally related carbohydrate derivatives featuring a similar dienic system have been used as starting materials for the construction of polyannulated products, suggesting that these cascade Pd(II)-mediated oxidative heterocyclizations are of value for various synthetic applications.
authors.affiliation: Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, UK.
authors.forename: Franck
authors.initials: F
authors.lastname: Silva
authors.forename: Maud
authors.initials: M
authors.lastname: Reiter
authors.forename: Rebecca
authors.initials: R
authors.lastname: Mills-Webb
authors.forename: Marcin
authors.initials: M
authors.lastname: Sawicki
authors.forename: Daniel
authors.initials: D
authors.lastname: Klär
authors.forename: Nicolas
authors.initials: N
authors.lastname: Bensel
authors.forename: Alain
authors.initials: A
authors.lastname: Wagner
authors.forename: Véronique
authors.initials: V
authors.lastname: Gouverneur