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문제 25b
Predict the product of the following Stille coupling reactions.
(b)
문제 31a
Predict the product of the following Sonogashira coupling reactions.
(a)
문제 31b
Predict the product of the following Sonogashira coupling reactions.
(b)
문제 32
The trimethylsilyl (TMS) group, used as a protecting group for alcohols, can also be used a protecting group for terminal alkynes. Show how TMS-acetylene could be used to link together two aryl halides using the Sonogashira reaction. [Hint: Deprotection of the TMS-acetylene can be done using KF in H₂O.]
문제 33a
Predict the product of the diorganocuprate cross-coupling reactions shown.
(a)
문제 33b
Predict the product of the diorganocuprate cross-coupling reactions shown.
(b)
문제 33c
Predict the product of the diorganocuprate cross-coupling reactions shown.
(c)
문제 34
Based on the stereochemical result alone, how can you tell that this reaction does not proceed by an Sₙ2 mechanism?
문제 35
Suggest a synthesis of the following molecule starting with the reagents shown, using cuprate cross-coupling as the key step.
문제 36a
Predict the product of the following epoxide opening reactions.
(a)
문제 36b
Predict the product of the following epoxide opening reactions.
(b)
문제 37
The situation shown here is an example where a cuprate is the only organometallic that will allow the product alcohol to be obtained. What is the problem with using a Grignard or an organolithium to attempt the same reaction?
문제 42
Which of the following solvents are reasonable choices for a Grignard reaction? Justify your choices. [Hint: Carbonyls are good electrophiles.]
문제 43
A chemist failed to generate the diol using the reaction shown here.
(a) Suggest a reason why this reaction did not work as written.
(b) How could the reaction conditions be modified to allow formation of the diol? [It may require more than one step.]
문제 44a
A chemist failed to generate the alcohol using the reaction shown here.
(a) Suggest a reason why this reaction did not work as written.
문제 44b
A chemist failed to generate the alcohol using the reaction shown here.
(b) How could the reaction conditions be modified to allow formation of the product?
문제 58
The following transformation is used as an early step in the synthesis of cilastatin, a drug used to counter antibiotic resistance. Identify a possible reagent for this step.
문제 59
Nitrogen-containing heterocycles form particularly stable carbenes and are commonly used as ligands in organometallic chemistry. (a) Why is the carbene shown particularly stable? [It may be helpful to draw the molecular orbital picture.]
