A New Asymmetric Synthesis of (+)-(3R, 4S, 5R, 7S)-Neoclausenamide via Intramolecular Nucleophilic Attack of Carbon Anion onto Cyclic Sulfate

摘要

An intramolecular nucleophilic substitution of carbon anion to cyclic sulfate was first employed in asymmetric synthesis of (+)-(3R, 4S 5R, 7S)-neroclausenamide 1 which is a novel hepatoprotective lactam isolated from the dry leaves of Chinese folk medicine Clausena lansium (Lour) Skeel. The regioselectivity of β-attack to this cyclic sulfate, just like its epoxide counterpart, was attributed to the increased reactivity of β-position by the phenyl