Electrocyclic reaction orbital correlation theory

Discuss Frontier Molecular Orbital (F.M.O.) method for pericyclic reactions. What are electrocyclic reactions Drawing correlation diagram, describe the comrotatoiy and disrotatory interconversion of cyclobutene and butadiene. Discuss Frontier Molecular Orbital (F.M.O.) method of analysing electrocyclic reactions. Derive selection rules for electrocyclic reactions. What are electrocyclic reactions Drawing correlation diagram discuss disrotatory and conrotatory interconversion of cyclobutene and butadiene. Support the results of correlation diagram by F.M.O. theory. 

Optical purity, by NMR, 13, 14 Orbital correlation diagrams, 196-203 cycloaddition reactions, 197-196 Diels-Alder, 198 ethylene -E ethylene, 198 electrocyclic reactions, 198-200 butadienes, 199 hexatrienes, 199 limitations, 203 photochemical, 201 Woodward-Hoffinann, 197 Orbital energies, see also Energies, orbital degeneracy, 27, 90 Orbital interaction theory, 34-71 diagram, 40, 42, 47 limitations, 69-71 sigma bonds, 72-86 Orbitals... 

It is possible to treat electrocyclic reactions in another way, namely, via a two-sided correlation diagram approach. This was first worked out by Longuet-Higgins and Abrahamson [14]. Only orbitals (occupied and unoccupied) that are involved in bonds being made or broken during the course of the reaction are included in the diagram. For butadiene, these are the four n MOs already familiar from simple Hiickel theory. For cyclobutene, they are the two n MOs associated with the isolated 2-center n bond and the two a MOs associated with the new C-C a bond. These orbitals and their energies are shown in Fig. 14-20. 

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