Preparation and a Novel Rearrangement Reaction of 1,2,3,4-Tetrahydro-9-hydroxy-b-carboline, and Their Applications for the Total Synthesis of (±)-Coerulescine

Novel 9-hydroxy-β-carboline derivatives were produced for the first time.A novel rearrangement reaction of 1,2,3,4-tetrahydro-9-hydroxy-β-carbolines was discovered to give 3,3-disubstituted oxindoles, which was successfully applied to the total synthesis of (±)-coerulescine.1-Hydroxyindoles undergo various types of reactions depending on the structures and reaction conditions. 2We have designed 1,2,3,4-tetrahydro-9-hydroxyβ-carbolines (1a-d, Scheme 1) as key substrates to elucidate whether the rearrangement of the 2-substituent to the 3-position 3a or vice versa, predicted by our