Dienophile electrostatic potential maps

Compare electrostatic potential maps for the following Diels-Alder transition states cyclopentadiene+ethene, cyclopentadiene+acrylonitrile and cyclopentadiene+ tetracyanoethylene, with those of reactants cyclopentadiene, ethene, acrylonitrile and tetracyanoethylene. Are electrons transferred from diene to dienophile in the transition states (relative to reactants) or vice versa For which reaction is the transfer the greatest The least Quantify your conclusion by measuring the total charge on the diene and dienophile components in the three transition states. 

In all the preceding cases, the double or triple bond of the dienophile is next to the positively polarized carbon of an electron-withdrawing substituent. Electrostatic potential maps show that the double-bond carbons are less negative in these substances than in ethylene (Figure 14.8). 

Diels-Alder reaction, 492 characteristics of, 492-497 dienes in, 496-497 dienophiles in. 493-494 electrostatic potential map of. 493 endo stereochemistry of, 495 HOMO in. 1188-1189 LUMO in. 1188-1189 mechanism of. 493 s-cis diene conformation in, 496-497... 

Use SpartanView to examine electrostatic potential maps of ethylene, benzoquinone, and 3,3,3-trifluoropropene. Which of these compounds are reactive as Diels-Alder dienophiles ... 

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See also in sourсe #XX -- [ ]

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