Abstract
Several attempts to predict directional selectivity of photoreactions on the basis of molecular orbital theory are described. Particularly, attention is paid to predict regioselectivity and periselectivity of 1, 7 sigmatropic shifts and electrocyclizations of singlet state of cycloheptatrienes by our new indices ΔGr, s ΔEr, s' and/or sudden polarization model, and to show how our new prediction model (T-K-H model) is applicable for organic chemists. In addition to our own works, several static indices and models for predicting photoreactive sites, which include ΔPr, s', π-electron density, second order perturbation energy in the excited states, and Brember's empirical model, are also introduced.
