A Concise and Free‐Metal Access to Lactone Annelated Pyrrolo[2,1‐a]isoquinoline Derivatives via a 1,2‐Rearrangement Step

An efficient approach to the previously unknown furo[2',3':2,3]pyrrolo[2,1-a]isoquinoline deriv-atives from readily available 1-R-1-ethynyl-2-vinylisoquinolines is described. The reaction fea-tures a simple procedure, occurs in hexaflouroisopropanol and does not require elevated tem-peratures. It has been found that the addition of glacial acetic acid significantly increases the yields of the target spirolactone products. Using trifluoroethanol instead of hexaflouroisopro-panol results into formation of pyrido[2,1-a]isoquinolines.