Topic 17: Organometallic reagents

17.1What is the definition of an organometallic compound?
 
17.2What three metals are particularly highlighted in this chapter?
 
17.3What change in oxidation state of the metal occurs when Li reacts with an alkyl halide? How about Mg?
 
17.4Does the same sort of thing happen in the reaction of copper(I) iodide with methyllithium?
 
17.5Given that information about oxidation state change of the metal, is the formation of an alkyllithium or Grignard reagent from an alkyl halide technically an organic oxidation or an organic reduction? If it is an oxidation, where did the electrons go? If it is a reduction, where did they come from? How many electrons are we talking about?
 
17.6Acetylides are a special fourth case (along with alkyllithiums, Grignard [pronounced GRIN-yard] reagents, and organocuprates). What makes them so special?
 
17.7[OK, here‘s the answer to Question 6: They are the only ones that can be formed by deprotonation by a strong base.] Approximately what is the pKa of 1-butyne? Given that pKa, which of the following bases could be used to remove that terminal proton — Na2CO3, NaOH, NaNH2, NaH, CH3Li?
 

Topic 18: Nucleophilic reactions of organometallic reagents

18.1Why is acetylide ion a better nucleophile than methyllithium? (two reasons)
 
18.2Methyllithium is such a strong base, it is generally only useful for one thing. What is that? (See Section 17.9A)
 
18.3sec-butylllithium and tert-butylllithium are never used as nucleophiles. Why is that?
 
18.4Section 17.9D overgeneralizes. What two (of the four) organometallic reagent types are the only ones that are genererally used for nucleophilic addition to ketones and aldehydes?
 
18.5All of these reagents are extremely reactive with water and O2. Thus, they must be used only by experienced professionals. In https://tinyurl.com/y88xnfq7>this video, what is the purpose of toluene, isopropanol, and dry ice? How do they work in this case?
 
18.6What are all the precautions taken by this graduate student that minimize the risk of explosion, fire, and exposure to harmful chemicals? (Two are surprisingly not mentioned but might be guessed.)
 
18.7Given that information, how is it that the mechanisms in your book involve H2O? [Hint: What is the difference in an organic synthesis laboratory between the reaction and the work up?]
 
18.8How can the reaction of these reagents with water be an advantage synthetically? [Hint: Two good answers, one involving isotopes.]
 
15 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)