chain and one oxygen atom closing the ring, meaning there are still six elements. γ-butyrolactone
will have five elements because it contains a bond between the ester oxygen and the third carbon
away from the carbonyl carbon. The five elements will be the oxygen, the carbonyl carbon, and
the three carbons in between.5 . D
With the same R groups, steric influence is the same in each case, so we can therefore rely solely
on electronic effects. When this is all that is taken into account, reactivity toward nucleophiles is
highest for anhydrides, followed by esters and carboxylic acids, then amides.6 . C
Anhydrides, particularly cyclic anhydrides, will form spontaneously from dicarboxylic acids when
heated.7 . A
Methylamine would react readily to form an amide. The less substituted the nucleophile, the
easier it will be for the nucleophile to attack the carbonyl carbon and form the amide. In fact,
triethylamine, choice (B), would not be able to form an amide at all because it does not have a
hydrogen to lose while attaching to the carbonyl carbon.8 . A
Propanamide is an amide; as such, it is the least reactive of the carboxylic acid derivatives
discussed in this chapter. Without strong acid or base, propanamide will not be able to undergo
nucleophilic acyl substitution and no reaction will occur.9 . D
β-lactams are amides in the form of four-membered rings; amides are generally the least reactive
type of carboxylic acid derivative. β-lactams experience significant ring strain from both eclipsing
interactions (torsional strain) and angle strain, and are therefore more susceptible to hydrolysis
than the linear form of the same molecule.10 . C
As far as we can tell, we are converting one ester to another in this reaction. The fact that this
reaction is acid-catalyzed should confirm the suspicion that this is a transesterification reaction.
11 . B