(a)
Interpretation:
The given reactions are final steps in one industrial synthesis of vitamin A acetate.
The mechanism has to be proposed for the acid-catalyzed cyclization in step-1.
Concept Introduction:
The ring cyclization occurs when an acyclic molecule reacts with acid. by the abstraction of proton from the acid molecule, internal bond shifting occurs to form the cyclization product.
(b)
Interpretation:
The given reactions are final steps in one industrial synthesis of vitamin A acetate.
The reagents has to be given for the reaction involved in step-2.
(c)
Interpretation:
The given reactions are final steps in one industrial synthesis of vitamin A acetate.
The mechanism has to be proposed for the formation of phosphonium salt in step-4.
(d)
Interpretation:
The given reactions are final steps in one industrial synthesis of vitamin A acetate.
The reagents that are involved in the reaction of step-3 has to be proposed.
(e)
Interpretation:
The given reactions are final steps in one industrial synthesis of vitamin A acetate.
Wittig reaction of step-5 has to be shown.
Concept Introduction:
Wittig reaction:
The reaction of carbonyl compound with the ylide of phosphonium salt to give an
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Chapter 16 Solutions
Organic Chemistry
- (b) Answer ALL parts (i)-(iv) of this question. The scheme below outlines a synthesis of a vitamin A analogue. (i) Suggest reagents for the conversion of 1 into 2 and write a mechanism for this reaction; (ii) Suggest a reagent for the conversion of 3 into 4; (iii) Propose a mechanism for the conversion of 4 into 5; (iv) Suggest reagents for the conversion of 5 into 6 and provide a mechanism for this transformation. reagents? 2 reagents? PPH3; HBr ÓH 3 4 PPH3 Br reagents?arrow_forward(b) Propose a mechanism for the following reaction, with curved arrows to show bonding changes. OH H2SO4 + THF HO HOarrow_forward(a) Draw the mechanism for the formation of both of the enols that can be formed from A (use acetic acid & AcOH as the source of the protons) (b) Draw the mechanism of reaction of this enol with bromine to give product Barrow_forward
- b) Listed below are several hypothetical nucleophilic substitution reactions. None is synthetically useful because the product indicated is not formed at an appreciable rate. In each case provide an explanation for the failure of the reaction to take place as indicated. OMe HO + OMe + OH HO + CH; OHarrow_forward2) a) n-Butyllithium is used to deprotonate the following compounds. Draw the structures of the resulting organolithium compounds (assume they are monomeric). Me₂N SO₂ b) Explain the selectivity of deprotonation. c) Each organolithium is reacted with ethyltosylate. Draw the structures of the resulting products.arrow_forwardShow how you would synthesize octan-2-one from each compound. You may use any necessary reagents.(a) heptanalarrow_forward
- (c) Suggest a synthesis of 2-methyl butanoic acid from butanoic acid, as shown below. You must pay attention to the stereochemistry and may use any reagents you deem necessary. OH Butanoic Acid OH 2-Methyl Butanoic Acidarrow_forwarda) Propose a synthesis route to prepare 3-methylhexan-3-ol from pentan-2-one. Note that more than one step reaction is required and you must show all the reaction steps including preparation of the intermediates.arrow_forward3) Propose a mechanism for the following reaction. HO H2SO4arrow_forward
- A common illicit synthesis of methamphetamine involves an interesting variation of the Birch reduction. A solution of ephedrine in alcohol is added to liquid ammonia, followed by several pieces of lithium metal. The Birch reduction usually reduces the aromatic ring, but in this case it eliminates the hydroxy group of ephedrine to give methamphetamine. Propose a mechanism, similar to that for the Birch reduction, to explain this unusual course of the reaction.arrow_forwardD H,O* CH,CI H,SO, H3C KMNO, + + ΗΝO, H A AICI, AICI, A Cl, FeCl, F+ G 7. Based on the reaction scheme above: (a) Draw the structural formula for compound A to H. (b) Show the mechanism for the formation of compound C. (c) Explain why the activating group, such as -OH is ortho and para director. Give an example of a compound from the reaction scheme. (d) Explain why a deactivating group, such as -NO2 is a meta director. Give an example of compound from the reaction scheme. Br2 FeBr3arrow_forwardb) The Wolf-Kishner reduction is a reaction used in Organic Chemistry to convert carbonyl functionalities into methylene group. The reaction was used to convert an aldehyde or ketone to an alkane using hydrazine, base and thermal conditions. The mechanism begins with the attack of hydrazine of the aldehyde or ketone. Stage 1: The reaction of aldehyde/ketone with hydrazine to produce hydrazine Stage 2: Reaction with the base and heat to convert hydrozone to alkane Write the mechanism of the reaction.arrow_forward
- Organic ChemistryChemistryISBN:9781305580350Author:William H. Brown, Brent L. Iverson, Eric Anslyn, Christopher S. FootePublisher:Cengage Learning