Synthesis of 5,6-dihydropyrrolo[2,1-a]isoquinolines via a TFA-promoted annulation of arylpropiolaldehydes and 1,2,3,4-tetrahydroisoquinolines

Abstract

A simple and efficient synthesis of a variety of 5,6-dihydropyrrolo[2,1-a]isoquinoline derivatives via an cyclization reaction between 3-arylpropiolaldehydes and 1,2,3,4-tetrahydroisoquinolines (THIQs) is reported. The reaction could be efficiently conducted by simply using trifluoroacetic acid (TFA) as the additive, which offered a variety of biologically existent pyrrolo[2,1-a]isoquinolines core with moderate to good yields.