Sequential carbophilic addition of organolithium reagents-N-acyliminium ion cyclization of N-phenenethylsuccinimide 3 yields pyrrolo[2,1-a]isoquinolones 1 in high yields, with the possibility of varying the substituent at C-10b by changing the organolithium. Application of this methodology to the cis-norbor-5-en-2,3-dicarboximide 7 using a functionalized organolithium reagent, the 3-(2-trimethylsilyl-1,3-dithian-2-yl)propyllithium 11, followed by desilylation and subsequent retro-Diels-Alder reaction affords the alpha,beta-unsaturated pyrroloisoquinolone 9b, immediate precursor of Erythrina-type alkaloids. Copyright (C) 1996 Published by Elsevier Science Ltd