Photo-induced Tungsten-catalyzed Cascade Synthesis of Pyrrolo[2,1-a]isoquinoline-1,3-dicarboxylate and its Reaction Mechanism

Tungsten-catalysed [3+2]-cycloaddition aromatization was developed. Mechanistic experiments revealed that the formation of an ion-pair intermediate is crucial for the cascade process. The cycloadduct acid was confirmed by X-ray diffraction.