Pressure Activation in Organic Synthesis

High pressure activation is presented as a potent synthetic strategy depending on the magnitude of the activation volume. Coupling of high pressure with ancillary activation methods such as catalysis widens the methodology. The application fields are reviewed: Diels-Alder reactions, 1,3- dipolar cycloadditions, [2+2] cycloadditions, Michael and related reactions, Baylis-Hillman additions etc... Many valuable substances can be synthesized in this way. Some recent developments are outlined, directed toward generation of pressure by water freezing, supramolecular chemistry, inhibition of steric hindrance.