Topic 42: The Claisen condensation

42.1What is a β-keto ester?
 
42.2What is the Claisen condensation (aka Claisen reaction)?
 
42.3What makes the Claisen condensation a "condensation"?
 
42.4What is the mechanism of the Claisen condensation involving ethyl acetate and sodium ethoxide?
 
42.5Why is sodium ethoxide preferred over NaOH or NaOMe in this reaction?

 
42.6Why does a Claisen condensation require a full equivalent of sodium ethoxide? Why not two?
 
42.7Why do you think we generally use hexanes and ethyl ether rather than ethyl acetate for work-ups in the organic lab?
 

Topic 43: Reactions related to Claisen condensations

43.1What is a crossed Claisen condensation?
 
43.2Compare the pKa values of acetone and ethyl acetate. Which is more acidic? Why is that? How does that relate to the reaction of a 5-keto ester with base?
 
43.3Under what circumstances might we expect a crossed Claisen condensation to be successful?
 
43.4What is the salient feature of an intramolecular Claisen condensation that makes it so valuable in organic synthesis?
 
43.5 Following up a Dieckmann condensation with aqueous base, acid, and heating, what do you get?
 
43.6What's with all these names?? What the heck. What is the Thorpe-Ziegler condensation?
 
43.7Why do organic chemists give peoples‘ names to reactions?
 
43.8Names are not particularly important here. What is important is ketones, aldehydes, and esters all undergo condensation reactions in the presence of base either with carbonyl compounds of their own kind or otherwise. What are examples of all six pairings of these three compound types?
 

Topic 44: Michael addition and Robinson annulation

44.1What‘s the twist on this story that makes for a Michael reaction?
 
44.2What is a Robinson annulation?
 
44.3What does “tandem” mean in the context of chemical reactions? (It is a little different from the general English language definition.)
 
44.4What two other named reactions did Robinson link together for his namesake annulation?
 
44.5In what field of organic synthesis has the Robinson annulation been of particular service?
 
20 questions
472 questions for Organic II

472 Questions for Organic II

Dearest Student. This web page is a set of questions I call Detailed Intended Learning Outcomes For Organic Chemistry (Part II). Some time ago I asked myself, "Bob, what do you think are the key questions that you hope students will be able to answer after taking Chemistry 248 at St. Olaf College?" So here you have them. Some are very simple; some require more thought. All are good questions to be thinking about as you read, discuss, and master the practical aspects of organic chemistry. They are discussion starters and review tips. There are no answers here (though there are some clues). The questions are here to help you focus on what's important (to me, at least!) and organize your learning process. The questions are grouped into topics. Bite-size chunks. Take them a few at a time. Don't feast on them all at one sitting!

(preliminary version 2021.01.15 feeback: Bob Hanson)