Diastereoselective Intramolecular α-Amidoalkylation Reactions of l-DOPA Derivatives. Asymmetric Synthesis of Pyrrolo[2,1-a]isoquinolines

Stereocontrolled intramolecular α-amidoalkylation reactions of l-DOPA-derived succinimides have been studied. Addition of MeLi to nonracemic succinimides 9a−d yields oxoamides, which are cyclized upon treatment with Lewis or protic acids to afford (5S,10bS)-trans 11 or (5S,10bR)-cis 12 pyrroloisoquinolines with variable diastereoselectivities, but with high enantiomerical purities (ee 99%).