Unprecedented Access of Functionalized Pyrrolo[2,1-a]isoquinolines from the Domino Reaction of Isoquinolinium Ylides and Electrophilic Benzannulated Heterocycles

We have come across an unexpected domino dipolar cycloaddition-ring opening reaction between electrophilic indoles and isoquinolinium methylides for accessing functionalized pyrrolo[2,1-a]isoquinolines. The reaction was found to be general yielding the products in good yields and scalable to gram-scale. We also observed the formation of S-S bridged bis-pyrrolo[2,1-a]isoquinolines from the reaction of 3-nitro benzothiophene and isoquinolinium methylides.