Asymmetric synthesis of both enantiomers of novel tetracyclic heterocycle, furo[3',2':2,3]pyrrolo[2,1-a]isoquinoline derivative via a diastereoselective N-acyliminium ion cyclization

Article abstract of DOI:10.1016/S0040-4020(96)01179-9

An efficient synthesis of both enantiomers of tetracyclic isoquinoline derivative (-)-2 and (+)-2 was accomplished starting from L-malic acid and L-tartaric acid, respectively. The key step is the stereoselective introduction of quaternary carbon-center in ring juncture using a diastereoselective N-acyliminium ion cyclization of chiral enamides (1, 3).