Synthesis of Karrikinolide Using the Aldol-Type Acetal Addition Reaction.

A short step total synthesis of karrikinolide has been achieved. Both α and α' positions of O-acylated acetol were alkylated by the boron-mediated aldol-type acetal addition reaction. The one-pot sequence including the Arbuzov reaction, intramolecular Horner-Wadsworth-Emmons reaction, acidic hydrolysis of acetals, and pyran formation provided karrikinolide. This procedure was applicable to the gram-scale synthesis of karrikinolide.