Orbital Interaction Between a Nucleophilic Radical and an Electron-poor Alkene

11 Orbital Interaction Between a Nucleophilic Radical and an Electron-poor Alkene 

Electron withdrawing substituents at the alkene, which lower the LUMO energy, increase the addition rate by reducing the SOMO-LUMO difference. Therefore, cyclohexyl radicals react almost 8500 times faster with acrolein than with 1-hexene.4 

The orbitals are crucial to the fact that a tert-buty radical reacts faster than primary or secondary radicals with alkenes such as vinylphosphinic esters or acrylonitrile. Thus, the increase in the SOMO energy on going from primary to tertiary radicals has a larger effect on the rate than the decrease in the strength of the bonds that are formed. Alkyl, alkoxyalkyl, aminoalkyl and other similar radicals are therefore nucleophiles. However, radicals with electron-withdrawing 

Basic Radical Chemistry General Aspects of Synthesis with Radicals 

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