Many abundant and highly bioactive natural alkaloids contain an indolizidine skeleton. A simple, high yielding method to synthesize this scaffold from N-heterocycles was developed. A wide range of pyridines, quinolines and isoquinolines reacted with donor-acceptor (DA)-aminocyclopropanes via an ytterbium(iii) catalyzed [3 + 2] annulation reaction to give tetrahydroindolizine derivatives. The pr...

Leontidine and camoensine, the main representatives of small quinolizidine-indolizidine alkaloid subgroup, are characterized by an inner bispidine system to which a 2-pyridone pyrrolidine fused on opposite sides. We efficiently synthesized both natural products from commercially available abundant cytisine, was converted into key intermediate, N-Boc-11-oxocytisine, iodine oxidation protection. ...

Alkyliminoacetonitrile derivatives were investigated as dienophiles in the Diels-Alder reaction. These activated imines react with dienes in intramolecular [4+2] cycloadditions to provide products with either the quinolizidine or indolizidine ring system, depending on the length of the tether connecting diene and dienophile. Quinolizidine cycloadducts are formed in good yield and with high ster...

Due to its tropical location, chains of mountains, inter-Andean valleys, Amazon basin area, eastern plains and shores on both the Atlantic and Pacific Oceans, Colombia has many ecosystems and the second largest plant biodiversity in the world. Many plant species, both native and naturalized, are currently recognized as toxic for both animals and humans, and some of them are known to cause their...