Concept explainers
(a)
Interpretation: For the alkylation of a given compound under two different conditions to form ketoesters A and B, and for each ketoester to form cyclic diketone C and D on treatment with methoxide ion in methanol,
The structure of A and B and indicate the conditions used in the alkylation to form the ketoester has to be given.
Concept introduction: Lithium diisopropylamide is a strong base. Therefore, it can abstract a proton from
Thermodynamic enolate ion is formed at temperature
(b)
Interpretation:
Mechanism for the conversion of keto ester A into cyclic diketone has to be given.
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Organic Chemistry, Books A La Carte Edition (8th Edition)
- The anticoagulant Warfarin can be synthesized by a conjugate addition (Michael addition) reaction as shown below: a) Propose a mechanism for the reaction starting from the enolate shown below. You can assume water is present for any proton transfers needed.b) We saw that the keto tautomer is normally preferred over the enol tautomer, however, the enol tautomer is present in the final product (Warfarin) and that is the more stable tautomer in this case. Why do you think the enol tautomer is more stable? Hint: consider the molecule as a whole.arrow_forwardWhat reagents ( A–D) are needed to carry out each reaction in the following sequence?arrow_forwardAnswer the following questions about curcumin, a yellow pigment isolated from turmeric, a tropical perennial in the ginger family and a principal ingredient in curry powder.a.In Chapter 11, we learned that most enols, compounds that contain a hydroxy group bonded to a C=C, are unstable and tautomerize to carbonyl groups. Draw the keto form of the enol of curcumin, and explain why the enol is more stable than many other enols. b.Explain why the enol O—H proton is more acidic than an alcohol O—H proton. c. Why is curcumin colored? d.Explain why curcumin is an antioxidant.arrow_forward
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- Even though B contains three ester groups, a single Dieckmann product results when B is treated with NaOCH3 in CH3OH, followed by H3O+. Draw the structure and explain why it is the only product formed.arrow_forwardDraw the mechanism of the following transformation using a Wittig reagent.arrow_forwardDraw a stepwise mechanism for the following Robinson annulation. This reaction was a key step in a synthesis of the steroid cortisone by R. B. Woodward and co-workers at Harvard University in 1951.arrow_forward
- Organic Chemistry: A Guided InquiryChemistryISBN:9780618974122Author:Andrei StraumanisPublisher:Cengage Learning