Flash Vacuum Pyrolysis

Flash vacuum pyrolysis (FVP) allows the generation, direct observation, and in many cases isolation of reactive intermediates and unusual molecules such as carbenes, nitrenes, free radicals, and cumulenes. Detailed characterization of unstable species is achieved in conjunction with matrix isolation or gas‐phase spectroscopic techniques. In addition, FVP has many important applications in organic synthesis, where reactions are often initiated by extrusion of small molecules (eg, N2, CO, CO2, or SO2), or by elimination (eg, HCl, CH3COOH, HNCO, or isobutene), or by (retro)pericyclic reaction. These reactions are chemoselective, stereospecific, and usually proceed via the lowest activation energy paths to the products, which are often formed in high yields. Photochemistry is often complementary to pyrolysis, and the two methods in combination are powerful tools in investigations of chemical reactions.