Molecular orbitals product formation rate

The overall results of substituent effects are observed in the products of a reaction, their rates of formation, and their stereochemistries. The purpose of this article is to apply very simple theoretical techniques to correlations and predictions of the rate and stereoselectivity effects of substituents in [2+2] photocycloadditions. The theoretical methods that will be used are perturbational molecular orbital (PMO) theory and its pictorial representation, the interaction diagram. Only an outline of the theory will be given below, since several more detailed descriptions are available. 4,18-34)... 

Oxidation rates of I ascorbic add (ASA) in a low dielectric solvent (MeOH) were determined, and initial autoxidation products were separated and identified. Mechanisms of ASA autoxidation were studied using the semi-empirical molecular orbital (MO) method. In this solvent, MeOH and in the absence of metals, ASA reacts with triplet oxygen yielding very similar to or nearly identical reaction products as those observed with singlet oxygen, suggesting the formation of ascorbate-2-peroxy-anion type intermediate.Mechanisms of ASA autoxidation including the formation mechanism of superoxide anion radical were proposed, which were supported by die MO calculation. 

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