Carbene Additions and Insertions

Molecular orbital calculations emphasize the importance of polar character in the structures of radicals that have both EWGs and EDGs. The stabilities of these structures can be readily understood using resonance theory, as shown to the right for an amino-cyano-substituted radical. 

The consequence of the captodative effect on radical additions to alkenes is a strong directing p effect for addition of the radical to the center that gives the especially stabilized radical. The captodative effect has been used in a variety of synthetic schemes, many of which are given in the reference below. 

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