Li, GuangPiemontesi, CyrilWang, QianZhu, Jieping2019-02-232019-02-232019-02-23201910.1002/anie.201813920https://infoscience.epfl.ch/handle/20.500.14299/154698Controlling the cis C20/C21 relative stereochemistry remains an unsolved issue in the synthesis of eburnane-type indole alkaloids. Provided herein is a simple solution to this problem by developing a unified and diastereoselective synthesis of four representative members of this class of natural products, namely, eburnamonine, larutensine, terengganensine B, and melokhanine E. The synthesis features the following key steps: a) an a-iminol rearrangement transforming the 3-hydroxyindolenine into spiroindolin-3-one, b) a highly diastereoselective conformation-directed cyclization leading to the melokhanine skeleton with the desired C20/C21 cis stereochemistry, and c) either an aza pinacol or an unprecedented aaminoketone rearrangement converting spiroindolinone back into the indole skeleton.alkaloidscyclizationsnatural productsrearrangementstotal synthesistext::journal::journal article::research article