- Pd(II)-catalyzed cascade Wacker-Heck reaction: Chemoselective coupling of two electron-deficient reactants
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A novel palladium(II)-catalyzed oxy-carbopalladation process was developed allowing for the orchestrated union of hydroxyynones with ethyl acrylate, two electron-deficient reactants. With β-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 β-hydroxyynones, these reactions proceed without affecting the stereochemical integrity of the existing stereocenters. In addition, tetrasubstituted furanones can be prepared when α-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.
- Silva, Franck,Reiter, Maud,Mills-Webb, Rebecca,Sawicki, Marcin,Klaer, Daniel,Bensel, Nicolas,Wagner, Alain,Gouverneur, Veronique
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p. 8390 - 8394
(2007/10/03)
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- Expeditious Routes to Multiply Functionalized Pyrans
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The scope of the Lewis acid catalyzed cyclocondensation reaction of activated dienes and aldehydes has been investigated.With a 3-(trialkylsilyl)oxy group in the basic diene, the reaction has been shown to be feasible with 1,1-dimethoxy, 1-(silyloxy)-1-al
- Danishefsky, Samuel,Harvey, Daniel F.,Quallich, George,Uang, Biing Jiun
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p. 392 - 393
(2007/10/02)
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