Unprecedented access to functionalized pyrrolo[2,1-]isoquinolines from the domino reaction of isoquinolinium ylides and electrophilic benzannulated heterocycles

We have come across an unexpected reaction between electrophilic indoles and isoquinolinium methylides for accessing functionalized pyrrolo[2,1- a ]isoquinolines. The reaction was found in general to yield the products in good yields. 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. The reaction between electrophilic benzannulated heterocycles and isoquinolinium methylides results in a domino dipolar cycloaddition-ring opening transformation, generating functionalized pyrrolo[2,1- a ]isoquinolines and S-S-bridged bis-pyrrolo[2,1- a ]isoquinolines.