Tethered Diels-Alder Cycloaddition: (±)-Neovibsanin B (Imagawa, Nishizawa), Valerenic Acid (Mulzer), (-)-Himandrine (Movassaghi), (±)-Pallavicinolide A (Wong), (+)-Phomopsidin (Nakada)
It has generally been observed that prospective intramolecular Diels-Alder cycloadditions that would form a γ-lactone are reluctant to proceed. 5-Ethynylpyridine-2-carbaldehyde web In the course of a synthesis of (±)-Neovibsanin B…