Is the trans-2-Butene Model Meaningful?
Real-World Manifestations
Medium-sized trans cycloalkenes have twisted double
bonds. For example, the twisted and pyramidalized nature
of the double bond in trans-cyclooctene has been experimentally
substantiated, and theory is in agreement with the experimental
structure. Figure 7 illustrates the twisted and
pyramidalized nature of the CC double bond in the trans
geometric isomer of cyclohexene, cycloheptene, cyclooctene,
and cyclononene. Distortion of the π bond can be illustrated
by viewing the calculated HOMO. For example, see Figure
8, which illustrates the HOMO in trans-cyclooctene.