Cryptopleurospermine (1), a 1, 2-secobenzylisoquinoline alkaloid was synthesized from hydrastinine derivative 2 and isovanillin 1, 3-propylene dithioacetal 3. The formation of CC bond between these two synthons involved addition of dilithio salt of dithian 3 to aldehyde group in 2. Reduction and hydrolysis of the masking group in addition product 4 furnished the synthesis.
