different products often possess different traits which affect their relative stability. If there is more
than one product, the major product will generally be determined by differences in strain or stability
between the two molecules. More strained molecules (with significant angle, torsional, or
nonbonded strain) are less likely to form than molecules without significant sources of strain.
Products with conjugation (alternating single and multiple bonds) are significantly more stable than
those without.
EXAMPLE REACTIONS
Now, we’ll apply these rules to three novel reactions. Focus on the decision-making element of this
process so that you will be able to apply the same logic to reactions that appear on Test Day.
Reaction 1
We’ll start with a series of reactions involving ethyl 5-oxohexanoate. First, it is reacted with 1,2-
ethanediol and p-toluenesulfonic acid in benzene; second, with lithium aluminum hydride in
tetrahydrofuran, followed by a heated acidic workup. What are the intermediates and final product?
Let’s go through the steps:
First, let’s draw out the reactants and reaction conditions.This molecule has an alkane backbone, a ketone, and an ester. Both of the carbonyl carbons
are electrophilic targets for nucleophiles. The carbonyl oxygens can also be reduced. Acidic α-
hydrogens are also present.For the first part of the reaction, we have a diol, which is commonly used as a protecting group
for aldehydes or ketones. Diols are nucleophiles because of lone pairs on the oxygens in the