Carbazoles are widely exploited for their interesting photophysical and electronic properties, however bay (4,5-) functionalization is challenging, and previously inaccessible through carbazole C-H activation. We report a simple methodology which...

We report a new method for the synthesis of novel N-aryl proline analogues. By reacting an aryne precursor with N-(2-malonyl) tetrahydropyridines in the presence of tetrabutylammonium fluoride (TBAF), a tandem aryne-capture/anion isomerisation/[2,3]-sigmatropic rearrangement is induced, leading to good yields of 3-substituted N-aryl-2-acylpyrrolidines. These products are known subunits of biological probes, sensors and drug-like fragments, and are not easily accessed directly by other methods. The reaction is also notable as the first [2,3]-rearrangement of cyclic ammonium ylides at room temperature.