1. Consider the reaction of 1-(2-(hydroxymethyl)phenyl)ethane-1-one (below) with base. a. OH Base 1-(2-(hydroxymethyl)phenyl)ethan- 1-one Using curved arrows, show the mechanism and expected product of this reaction. b. What type of reaction is this? (I.e., aldol, nucleophilic acyl substitution, etc.) C. What type of compound is the product?

1. Consider the reaction of 1-(2-(hydroxymethyl)phenyl)ethane-1-one (below) with base. a. OH Base 1-(2-(hydroxymethyl)phenyl)ethan- 1-one Using curved arrows, show the mechanism and expected product of this reaction. b. What type of reaction is this? (I.e., aldol, nucleophilic acyl substitution, etc.) C. What type of compound is the product?

Organic Chemistry: A Guided Inquiry

2nd Edition

ISBN:9780618974122

Author:Andrei Straumanis

Publisher:Andrei Straumanis

Chapter26: Aldol And Claisen Reactions

Section: Chapter Questions

Problem 9E

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f. Additional Questions: 1) For each reaction - identify the nucleophile and electrophile, the type of mechanism (e.g. SN1, E2, etc.) and draw the major product(s) a. e. OK OH -OK d. CH³CH₂OH + HBr → OTS OH x Br NaOH 1) PBr3 Br 2) KCI/ acetone 6
Why we need step 3 before step 4? a. Because the nitro group increases the electrophilicity at the ortho positions which is where the bromine is added. b. Because the amine group is a strong ortho, para director which is what controls the regiochemical outcome of this bromination. c. Step 4 is unessesary. The symmetry of compound 3 allows for the bromination to be regioselective and give compound 5. 5. There will be a mixture of products because there is no selectivity for a major product.
Write structures for the carbonyl electrophile and enolate nucleophile that react to give the aldol below. OH H You do not have to consider stereochemistry. • Draw the enolate nucleophile in its carbanion form. Draw one structure per sketcher. Add additional sketchers using the drop-down menu in the bottom right corner. Separate multiple reactants using the sign from the drop-down menu. ? ChemDoodle Sn [F
1. The dramatic reaction below was reported in the Evans synthesis of colchicine in 1981. MeO. ÇO,Me -CO,Me MeO, OMe CF3CO2H MeO OMe Meo OMe OMe A. Label reactant carbon atoms 1-7 in the product and circle the single bond made in the product through an electrophilic aromatic substitution process. B. Add curved arrows and a reactive intermediate below to show how the starting materials of this reaction convert to intermediate A via 1. pt; 2. [AE + SN2]. CO, Me OH Мео. OMe pt MeO ÓMe F3CCO2-H [AE + SN2] Meo, -CO2ME MeO OH -02CCF3 ÓMe OMe A. OH
6. Draw out the mechanism of the final step(s) of each reaction scheme (i.e., mechanism that starts at the indicated intermediate (A-C) and ends in the final product N-benzyl-3- phenylpropanamide). Use curved arrows to indicate the flow of electrons. Be sure to show any intermediates that are formed along the way. Show any by-products besides the ones provided. Scheme 1: Acid Chloride Route O: -R ö: Many steps -CO2 -co -HCI
10. Explain the reaction shown below. Include the following pieces in your explanation. Identify the electrophile and the nucleophile. Draw a curved arrow mechanism for this reaction. (Assume an acidic work-up). Explain the electron flow. Indicate any regiochemical or stereochemical preferences. one b. c. d. LIAIH4 OH one
4. If you were to try to do the reaction below, theoretically 8 different aldol reactions (ignoring stereochemistry and possible aldol condensation products) could occur. Some may be easier than others and, overall, this is likely a difficult reaction given the two ketone starting materials. a. Provide all 8 theoretically possible products for this reaction. b. How could you change the reaction conditions to favor the formation of just one of the 8 possible products. It can be any of the products but you must give at least one specific step that could be taken to help increase selectivity. L NaOH
a. What are the products of following reactions?b. Write the reaction mechanism for each using the right arrows and define it as Sn2, Sn1, E2 or E1.c. Explain why do you choose that product and mechanism or in case something else happens explain why.
5. Retrosynthesis. Suggest how the molecules mentioned below can be synthesized (give the reagents and intermediate compounds to arrive at the target product. (choose only one) CH3 CH3 H3C Br A. B. CH3 'H CH3 form
10. Explain the reaction shown below. Include the following pieces in your explanation. a. Identify the electrophile and the nucleophile. b. Draw a curved arrow mechanism for this reaction. (Assume an acidic work-up). Explain the electron flow. Indicate any regiochemical or stereochemical preferences. C. d. LIAIH4 OH
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