Tandem Pictet-Spengler/oxidation reaction: One-step synthesis of β-carbolines oxidized by Ca(ClO)2

A novel and efficient one-pot synthesis of β-carboline derivatives through a tandem Pictet-Spengler/oxidative aromatization sequence using calcium hypochlorite (Ca(ClO)₂) as a mild oxidant has been reported. This methodology enables the direct conversion of readily available tryptamine derivatives and aldehydes in methanol to afford the corresponding β-carboline products in moderate to excellent yields (34–92 %). Notably, this protocol eliminates the need for isolation of the intermediate 1,2,3,4-tetrahydro-β-carbolines, thereby significantly streamlining the synthetic process. The operational simplicity, good functional group tolerance, and avoidance of harsh reaction conditions make this method a practical approach for the synthesis of β-carboline scaffolds, which are privileged structures in medicinal chemistry.