Total synthesis of dl-coccuvinine 1a and dl-coccolinine 2a, "abnormal-type" erythrinan alkaloids lacking the C(16) O-function at the aromatic ring, was effectively achieved by using the Diels–Alder reaction of dioxopyrroline. Isoquinolinopyrrolinedione 6a, a key dienophile, was synthesized via the tetrahydroisoquinoline 5a, which was prepared by Bischler–Napieralski cyclization of the amide 4a at the unactivated position. The Diels–Alder adduct 7a of 1,3-bis(trimethylsilyloxy)-butadiene with 6a with converted stereoselectively into these alkaloids in short steps.