Organic Chemistry CHM 252 and CHM 254L

CHM 252 Organic Chemistry II
Spring 2001
Workshop #9

1.  Propose a mechanism to account for each of the following transformation:

2.  List the following compounds in order of decreasing K_eq for hydrate formation (That is, from most reactive to least reactive). Recall that a K_eq > 1 is equivalent to a DG_rxn that is negative (spontaneous) according to DG_rxn = -RT ln K_eq.

3.  Discuss (in detail) which of the two compounds listed below is more or less reactive in nucleophilic acyl substitution. Draw completely labeled reaction energy diagrams to support your rationale. (HINT: There are basically two primary reasons that you need to address).

(a) 3,3,3-trifluoropropanoyl chloride (b) propanoic acid

4.  Assume that each of the following esters can be hydrolyzed to the corresponding carboxylic acid and alcohol under acidic conditions as follows (acid-catalyzed hydrolysis of an ester).

(a) List the following esters in order of decreasing reactivity in the first part of nucleophilic acyl substitution (formation of the TAI via addition). Explain your ordering.

(b) List the following esters in order of decreasing reactivity in the second part of nucleophilic acyl substitution (collapse of the TAI and expulsion of the leaving group via elimination). Explain your ordering.

(c) Overall, considering your answers to parts (a) and (b), which compound do you think is the most reactive in NAcS?  Explain.

HINT: You'll definitely want to refer to the extra handout that I gave you in class on Tuesday!

(d) Work through the mechanism of hydrolysis for any ONE of the compound listed above.

Timm A. Knoerzer
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Naz Chem. Dept.
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Last Updated Monday, March 26, 2001 06:48:55 PM