1,3-dipolar cycloaddition chemistry for the preparation of novel indolizinone-based compounds

The beta-carbolinone core structure present in a variety of alkaloids was efficiently prepared from 5-oxo-1,2,3,5-terahydroindolozine-6-trifluoromethanesulfonate precursors. Allylation of methyl 6-hydroxy-5-oxo-1,2,3,5-tetrahydroindolizine-8-carboxylate gave the corresponding ethers, which subsequently underwent thermal Claisen rearrangement to afford the C-allyl products in high yields.