Electrophilic addition reactions energy changes

Finally, consider the addition of an experimentally ambiphilic carbene (MeOCCl) to a simple alkene (e.g., propene). Now the carbene and aUcene FMO s are roughly in balance both differential FMO energies will be comparable. This is depicted in the A Case of Fig. 6. Now changing the alkene s Me substituent to BuO will raise both the K and 7t orbital energies of the alkene, and convert the A Case to the N Case i.e., the addition reaction will become electrophilic. Alternatively, changing propene s Me substituent to CN will convert the A Case to the N Case the addition reaction will become nucleophilic. Of course, these imaginary manipulations describe the behavior of an ambiphilic carbene, and the expression of these thought experiments is represented by the relative reactivities of MeOCCl collected in Table 2. 

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