Stereoselective Total Synthesis of (±)-Pleurospiroketals A and B.
Sagar S ThoratRama Krishna GamidiRavindar KonthamPublished in: The Journal of organic chemistry (2021)
A full account of our efforts toward the stereoselective total synthesis of sesquiterpenoid-derived natural products (±)-pleurospiroketals A and B is described. Commercially available 3-methyl-2-cyclohexenone and 2,2-dimethyloxirane were used as key building blocks, and the substrate-controlled stereoselection was exploited to access the entire stereochemistry of these natural products. Initially, a planned synthetic route involving a [6,5]-bicyclic lactone intermediate was found to be insurmountable, and the later strategy comprising OsO4-NMO-mediated dihydroxylation of 3-methyl-2-cyclohexenone, followed by Luche reduction, Eschenmoser methylenation, and Brønsted acid-induced spiroketalization steps, was ultimately identified as the reliable strategy.
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