Organic Synthesis at High Temperatures. Gas‐Phase Flow Thermolysis [New Synthetic Methods (57)]

The preference for carrying out synthetic organic reactions at the lowest possible temperature is due to the expectation that the selectivity often increases with decreasing temperature, as is confirmed by many examples and also theoretically justified. Selectivity, however, is not the only problem at high temperatures; further factors include the frequently limited thermal stability of the functional groups and structural elements not directly involved in the transformation. In spite of these limitations, the advantages of high temperatures and the greatly improved knowledge of the mechanisms of dynamic gas‐phase processes accumulated in recent years can be exploited in directed organic synthesis. In this review the synthetic potential of gas‐phase flow thermolysis will be described from the viewpoint of the synthetic chemist with the aid of typical examples of application.