Dienes local softness

Table 10.11 gives the value of the local softness for some representative diene and dienophiles. 

Table 10.11. Local Softness Parameters for Dienes and Dienophiles ...

Equations (10.4) and (10.5) is the fact that the more remote positions (4 and 2 ) change less than the substituted positions. Local softness parameters have also been calculated by a bond electronegativity equalization approach.All the computations reported to date refer to diene (HOMO)-dienophile (LUMO) combination pairs, so it is not possible to see if this approach successfully predicts the case in which both the diene and the dienophile carry EWG substiments. 

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