Vital role of entropy in photochirogenesis

The effects of temperature, pressure, solvent, and substrate concentration upon several enantio- and diastereodifferentiating photochemical reactions have been investigated and discussed in detail. These entropy-related external factors, which manipulate the weak electronic and steric interactions in the excited state, dynamically control the stereochemical outcome of asymmetric photochemical reactions, and even switch the product chirality. A global view on the entropy chemistry and its potential applications are also discussed.