A Concise and Divergent Approach to the Naturally Occurring Tetracyclic Clavine Alkaloids (+)-Lysergol, (+)-Lysergine, and (+)-Isolysergine

A concise and divergent asymmetric synthesis of the tetracyclic clavine alkaloids (+)-lysergol, (+) lysergine, and (+)-isolysergine has been accomplished using a novel strategy involving a chemoselective MeOH-mediated oxa-Michael addition and lactone-lactam rearrangement of appropriately functionalized spiro α-methylene-γ-butyrolactones, efficiently prepared from (R)-4-amino-Uhle's ketone and bromomethyl acrylate. The straightforward downstream modifications complement and expand upon previous asymmetric total syntheses of these natural products.