A convenient synthesis of indole and 1,4-dihydropyridine hybrid macromolecules by dimerization of [2-(1h-indol-3-yl)ethyl]pyridinium salts
The design and synthesis of a novel type of macrocyclic compounds containing indole and 1,4-dihydropyridine heterocyclic subunits is presented. The key reaction involved in the synthesis was a base-mediated dimerization of [2-(1H-indol-3-yl)ethyl]pyridinium salts. The structure of the macrocycles was unambiguously confirmed by NMR and HRMS spectroscopic and X-ray single crystal diffraction.
Construction of Chiral Tetrahydro-β-Carbolines: Asymmetric Pictet–Spengler Reaction of Indolyl Dihydropyridines
A highly efficient synthesis of the enantioenriched tetrahydro-β-carbolines was developed by using a chiral phosphoric acid catalyzed Pictet–Spengler reaction of indolyl dihydropyridines. The reaction proceeds under mild reaction conditions to afford the desired chiral tetrahydro-β-carbolines in good to excellent yields (up to 96 %) and high enantioselectivities (up to 99 % ee). With this method, a formal synthesis of tangutorine and a total synthesis of deplancheine were achieved in a highly efficient manner.