Pictet-Spengler Reaction Revisited: Engineering of Tetherd Biheterocycles into Annulated Polyheterocycles

This micro review focuses on the application of the modified Pictet-Spengler reaction to the synthesis of diverse polyheterocycles with structural resemblance to natural products. The modified Pictet-Spengler reaction takes use of tethered biheterocycles comprising nucleophilic partner and a source for electrophilic partner followed by their condensation with aldehydes/ketones to furnish annulated polyheterocycles. Using this strategy engineering of numerous tethered biheterocycles into annulated polyheterocycles has been successfully carried out using both 6-endo as well as 7-endo cyclizations.