Advantages of continuous-flow technologies for organic synthesis include facile automation, reproducibility, energy efficiency, precise control of reaction parameters and the restriction of by-product formation often caused by prolonged heating.

Magnus Rueping and co-workers, Aachen University, Germany, report the first simple and efficient continuous-flow method for the hydroarylation of arenes and heteroarenes. The process is suitable for various styrenes and employs the heterogeneous catalyst, amberlyst-15.

The reactions were sequentially introduced into the flow cell and performed several times without having to change the catalyst. A series of 1,1-diarylalkanes was produced in good yields (typically 60-95 %), and scale up of this method was achieved to produce diarylmethanes in multigram quantities.

• Efficient and General Continuous-Flow Hydroarylation and Hydroalkylation of Styrenes
  M. Rueping, T. Bootwicha, E. Sugiono,
  Adv. Synth. Catal. 2010, 352 (17), 2961-2965.
  DOI: 10.1002/adsc.201000538