Ozone HOMO-LUMO interactions

The cycloaddition can also be analyzed in terms of HOMO-LUMO interactions (see page 756), with the interaction of the LUMO of ozone and the HOMO of the alkene being dominant. For a discussion, see Kuczkowski, R. L. in Padwa, A., Ed. 1,3-Dipolar Cycloaddition Chemistry, Vol. 2 Wiley-Interscience New York, 1984 pp. 197-276. 

This type of dipolar addition reaction was introduced in chapter 3 in connection with ozonolysis (sec. 3.7.B), as well as permanganate (sec. 3.5.A),346 and osmium (sec. 3.5.B) oxidation of alkenes. Ozone is a classical example of a dipolar molecule (see canonical forms of 424 +0—O—0 and 0—O—0+). Fleming showed that the HOMO/LUMO orbitals of ozone interact with those of ethene (as shown in Figure 11.21).347... 

C with BCP (3) most likely for the preferred interaction of the high lying HOMO of BCP with the low lying LUMO of ozone. 

Interaction of the HOMO of ozone with the LUMO of the alkene, and of the LUMO of ozone with the HOMO of the alkene are symmetry allowed. Just as with [4+2]-cycloaddition, the energy difference of these orbitals will control the facility of the reaction. In general, the low-energy interaction is the one between HOMOdipoie and LUMOalkene-... 

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