Synthetic studies on indole alkaloids. III. Synthesis of 1-ethylindolo[2,3-a] quinolizidin-2-one

Article abstract of DOI:10.1016/S0040-4039(00)97469-0

The synthesis of 1-ethylindolo[2,3-a]quinolizidin-2-one 3 is reported by potassium tert-butoxide cyclization of N-hydroxyethyl-2-[1-(phenylsulfonyl)-3-indolyl]-4-piperidone ethylene acetal 10 followed by acid treatment of the intermediate spiroindolenines