The four T orbitals of 1, 3-butadiene are of the following symmetries under the preserved symmetry plane( see the orbitals in Fig.55):π=e,丌2=o,π3=e,π4=0.The T and T and o and o orbitals of the product cyclobutane, which evolve from the four orbitals of the 1, 3-butadiene, are of the following symmetry and energy order o=e, I e,T=0,0=o The Woodward-Hoffmann rules instruct us to arrange the reactant and product orbitals in order of increasing energy and to then connect these orbitals by symmetry, starting with the lowest energy orbital and going through the highest energy orbital. This process gives the following so-called orbital correlation diagram T Figure 5.6 The orbital correlation diagram for the 1, 3-butadiene to cyclobutene reaction We then need to consider how the electronic configurations in which the electrons are arranged as in the ground state of the reactants evolves as the reaction occurs We notice that the lowest two orbitals of the reactants, which are those occupied by the four T electrons of the reactant, do not connect to the lowest two orbitals of the14 The four p orbitals of 1,3-butadiene are of the following symmetries under the preserved symmetry plane (see the orbitals in Fig. 5.5): p1 = e, p2 = o, p3 =e, p4 = o. The p and p* and s and s* orbitals of the product cyclobutane, which evolve from the four orbitals of the 1,3-butadiene, are of the following symmetry and energy order: s = e, p = e, p* = o, s* = o. The Woodward-Hoffmann rules instruct us to arrange the reactant and product orbitals in order of increasing energy and to then connect these orbitals by symmetry, starting with the lowest energy orbital and going through the highest energy orbital. This process gives the following so-called orbital correlation diagram: Figure 5.6 The orbital correlation diagram for the 1,3-butadiene to cyclobutene reaction. We then need to consider how the electronic configurations in which the electrons are arranged as in the ground state of the reactants evolves as the reaction occurs. We notice that the lowest two orbitals of the reactants, which are those occupied by the four p electrons of the reactant, do not connect to the lowest two orbitals of the s * s p * p p4 p3 p2 p1