One-pot enantioselective construction of indoloquinolizidine derivatives bearing five contiguous stereocenters using aliphatic aldehydes, nitroethylenes, and tryptamine

An organocatalytic cascade reaction was established for the construction of indoloquinolizidine derivatives bearing five contiguous stereo-centers from readily available aliphatic aldehydes, nitroethylenes, and tryptamine. This one-pot process gave 30-55% overall yields with excellent d.r. (> 20:1 in all cases) and ee (91-98%). Additionally, quaternary stereogenic carbon center-containing indoloquinolizidines were prepared through NBS-mediated cyclization of one of the intermediates.