Orbital-controlled reactions

In some cases the site of attack is in no doubt, e.g., 9 adds PMe3 at the carbyne carbon in an orbital-controlled reaction (29,31) ... 

It is convenient to separate the total electron density at each atom into a- and 71-components. It is likely to be the 7t-density that will be important in reactions with nucleophiles, since in an orbitally controlled reaction (Chapter 1) the donor orbital of the incoming nucleophile will initially interact with the lowest vacant 7i -orbital. The overall pattern of charge alternation is repeated in both the 7t- and the a-electron densities, and nucleophiles are expected to attack at the 2- or 4-positions. This is exactly the pattern that is seen in... 

It is demonstrated that besides ionic interactions, covalent interactions can be important in zeolitic systems. Then, besides acid strength, the concept of acid softness-hardness in zeolites needs to be considered and its importance to explain selectivity effects in orbital controlled reactions is discussed. The influence of zeolite composition and pore structure (electronic confinement) on acid softness-hardness, and orbital control, and their effects on para/ortho selectivity during alkylation of toluene by methanol in large pore zeolites is presented. 

Corma A, Llopis F, Viruela P, Zicovich Wilson CM Acid softness and hardness in large pore zeolites as a determinant parameter to control selectivity in orbital controlled reactions. 

Next, we consider the first order mixed derivatives of the energy with respect to electron and spin number on one hand and the external potentials v and V5 on the other hand. These derivatives are generalizations of the Fukui function, the reactivity index used to probe frontier orbital-controlled reactions. The generalized Fukui function /jvjv can be considered as the spin-resolved extension of the regular Fukui function given in eqn (26)... 

Hence, both Fukui functions are usefid reactivity descriptors especially for orbital controlled reactions. Considering the Eqs. 8.6 and 8.7, it is easy to see that the Fukui function integrates to one ... 

---