C-10b Functionalized 5,6-dihydropyrrolo[2,1-a]isoquinolines as intermediates in the synthesis of erythrinane systems. Intra- vs. intermolecular conjugate addition based strategies

C-10b Functionalized 5,6-dihydropyrrolo(2,1-a)isoquinolines have been prepared via Parham cyclization and α-amidoalkylation reactions, using functionalized organolithium reagents. Their utility as intermediates in the synthesis of erythrinanes via intra or intermolecular conjugate addition reactions has been studied. Thus, a protocol for preparing the erythrinane skeleton through a Parham cyclization−intermolecular α-amidoalkylation−intermolecular conjugate addition−ring-closing metathesis process has been described.