A short diastereoselective synthesis of 1-aminoindolo-[2,3-a]quinolizidines via an N-acyliminium ion cyclisation

Article abstract of DOI:10.1016/S0040-4039(99)01922-X

trans 1-Aminoindolo[2,3-a]quinolizidines were synthesised using an intramolecular Pictet-Spengler-like reaction. Starting from commercially available N-Cbz-L-glutamic acid, indoloquinolizidines were obtained in only five steps with good yields. This improved synthesis is the result of both a highly regioselective imide reduction and a highly diastereoselective reaction using N-acyliminium ions.