An enantioselective route to paeonilactone A via palladium- and copper-catalyzed reactions.
We herein report on a formal total synthesis of paeonilactone A involving palladium-, copper-, and enzyme-catalyzed reactions starting from 1,3-cyclohexadiene. The key step in the synthesis, a palladium(II)-catalyzed 1,4-oxylactonization of a conjugated diene, simultaneously introduces two of the oxygen substituents required for the target molecule. The synthesis also includes our recently developed copper(I)-catalyzed cross-coupling reaction between dienyltriflates with Grignard reagents, introducing one of the methyl groups present in the target molecule. This new approach toward paeonilactone A allows complete control of all four stereogenic centers and is the first enantioselective route toward paeonilactone A starting from an achiral substrate.
Jonasson
C
C
Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, Sweden.
Rönn
M
M
Bäckvall
J E
JE
D002384:Catalysis; D003300:Copper; D007202:Indicators and Reagents; D007783:Lactones / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D010084:Oxidation-Reduction; D010165:Palladium; D010946:Plants, Medicinal / Q000737:chemistry*
D007202:Indicators and Reagents; D007783:Lactones; C408125:paeonilactone A; D010165:Palladium; D003300:Copper