27: Decarboxylations
- Page ID
- 150984
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Name: ______________________________
Section: _____________________________
Student ID#:__________________________
Another Pericyclic Reaction: Decarboxylation
β-keto acids (shown below) spontaneously decarboxylate in the mechanism shown.
- What is the final product in this sequence?
- Draw the mechanism for decarboxylation of this compound.
- Show the product of these reaction sequences:
Application Problems
- Treatment of (R,S)-2,3-dibromo(4-methoxyphenyl)propanoic acid with potassium carbonate in 2-butanone at 80°C gave a product with the Mass Spectra and 1H NMR spectral data given below.
Product: 1H NMR: 7.60 (d, 2H, J = 11 Hz), 7.28 (d, 2H, J = 11 Hz), 6.88 (d, 1H, J = 9 Hz), 6.38 (d, 1H, J = 9 Hz), 3.78 (s, 3H). MS: molecular ions with m/z 212/214 (of equal height).
- Draw the starting material with the correct stereochemicstry.
- Fully analyze this spectral data and show the structure of the product.
- Provide amechanism that clearly explains for the regioselectivity of the product.
- Step 3 of the TCA Cycle is the conversion of isocitrate to α-ketoglutarate (shown below). This reaction is catalyze by isocitrate dehydrogenase and it utilizes NAD+ and a divalent cation such as Mg+2.
- Propose a mechanism for this reaction. Show all of the steps and include the NAD+ and Mg+2 in your mechanism.
- Is this an oxidation reaction? Show calculations.