Unveiling the N‐Nucleophilicity of Non‐Aromatic Pyrroles Through Rhodium Catalysis: A Case of Synthesis and Luminescence Studies of Pyrrolo[2,1‐a]isoquinolinium Salts

Abstract

An expedient synthesis of hitherto unknown pyrrolo[2,1a]isoquinolinium salts from non-aromatic aryl-substituted 2Hand 3H-pyrroles and internal alkynes has been developed. The process represents a rare example of N-nucleophilic reaction of 2H-and 3H-pyrroles and relies on the ortho-CÀ H bond activation of non-aromatic arylpyrroles in the presence of rhodium catalyst followed by alkyne annulation reaction. A broad range of diversely substituted salts was obtained in high yields under mild reaction conditions. The photophysical properties for selected representatives of novel pyrrolo[2,1a]isoquinolinium salts have been evaluated to demonstrate their potential as fluorescent materials for light-emitting devices and bioimaging.