ChemInform Abstract: Tandem Carbophilic Addition‐N‐Acyliminium Ion Cyclization for the Synthesis of Functionalized Pyrrolo(2,1‐a)isoquinolones: Key Intermediates for the Preparation of Erythrina‐Type Alkaloids.

Abstract

Tandem Carbophilic Addition-N-Acyliminium Ion Cyclization for the Synthesis of Functionalized Pyrrolo(2,1-a)isoquinolones: Key Intermediates for the Preparation of Erythrina-Type Alkaloids.-Carbophilic addition of organolithium reagents (II) to the succinimide (I) gives a mixture of the adducts (III) and (IV) which on treatment with TFA yield the pyrroloisoquinolines (V) via cyclization of an intermediate N-acyliminium ion. Application of this methodology to educt (VI) provides the compound (IX) which is subjected to retro-Diels-Alder reaction, affording the α,β-unsaturated pyrroloisoquinolone (X), immediate precursor of Erythrina-type alkaloids. -(MANTECA, I.; SOTOMAYOR, N.; VILLA, M.-J.; LETE, E.; Tetrahedron Lett. 37 (1996) 43, 7841-7844; Dep. Quim. Org., Fac. Cienc., Univ. Pais Vasco,