Organo-cation-catalyzed site-selective sequential alkylation of dimeric 2-oxindoles: a concise catalytic approach to (+)-calycanthidine and (+)-idiospermuline

The total synthesis of bis(cyclotryptamine) alkaloids has been realized via the development of an organo-cation-catalyzed (C5) site-selective, enantioselective (94% ee) and diastereoselective (dr > 20 : 1) sequential alkylation.