A practical approach to the fused β-carboline system. asymmetric synthesis of indolo [2, 3-a] indolizidinones via a diastereoselective intramolecular α-amidoalkylation …
A Ardeo, E Garcı́a, S Arrasate, E Lete, N Sotomayor
Fused β-carboline systems, as indolo [2, 3-a] indolizidinones, indolo [2, 3-a] quinolizidinones, their 2-oxa analogues, and benzo [a] indolo [2, 3-a] indolizidinones are prepared efficiently via an RLi addition-N-acyliminium ion cyclisation sequence on readily available imides. In an enantioselective variant of these α-amidoalkylation reactions, the addition of MeLi to a chiral non-racemic imide derived from tryptophan yielded an oxo ...