Oxidation and Reduction

Question: In the $\mathit{C}{\mathit{r}}^{\mathbf{6}\mathbf{+}}$oxidation of cyclohexanols, it is generally true that sterically hindered alcohols react faster than unhindered alcohols. Which of the following alcohols should be oxidized more rapidly?

Question: Classify each reaction as oxidation, reduction, or neither

a.

b.

c.

d.

Question: What alkane is formed when each alkene is treated with H₂ and a Pd catalyst?

a.

b.

c.

Question: Draw all alkenes that react with one equivalent of H₂ in the presence of a palladium catalyst to form each alkane. Consider constitutional isomers only

a.

b.

c.

Question: Which alkene in each pair has the larger Heat of hydrogenation?

a.

b.

Question: Explain why heats of hydrogenation cannot be used to determine the relative stability of 2-methylpent-2-ene and 3-methylpent-1-ene.

Question: Given that syn addition of H₂ occurs from both sides of a trigonal planar double bond, draw all stereoisomers formed when each alkene is treated with H₂ .

a.

b.

c.

Question: Complete the missing information for compounds A, B, and C, each subjected to hydrogenation. The number of rings and π bonds refers to the reactant (A, B, or C) prior to hydrogenation.

Question: Draw the compounds formed when triacylglycerol A is treated with each reagent, forming compounds B and C. Rank A, B, and C in order of increasing melting point.

A.

a.  (excess), Pd-C (Compound B) 

b.   (1 equiv), Pd-C (Compound C)

Question: Which alkyne has the smaller Heat of hydrogenation $\mathrm{HC}\equiv {\mathrm{CCH}}_2{\mathrm{CH}}_2{\mathrm{CH}}_3 \mathrm{or} {\mathrm{CH}}_3\mathrm{C}\equiv {\mathrm{CCH}}_2{\mathrm{CH}}_3$ ? Explain your choice.

Question: What is the structure of cis-jasmone, a natural product isolated from jasmine flowers, formed by the treatment of alkyne A with H₂ in the presence of the Lindlar catalyst?

Question: a) Draw the structure of a compound of molecular formula  C₆H₁₀  that reacts with H₂ in the presence of Pd-C but does not react with H₂ in the presence of Lindlar catalyst. (b) Draw the structure of a compound of molecular formula C₆H₁₀  that reacts with H₂  when either catalyst is present

Question: What product is formed when ${\mathrm{CH}}_3{\mathrm{OCH}}_2{\mathrm{CH}}_2\mathrm{C}\equiv {\mathrm{CCH}}_2\mathrm{CH}{\left({\mathrm{CH}}_3\right)}_2$ is treated with each reagent: (a) H₂   (excess), Pd-C; ; (b) H₂ (1 equiv), Lindlar catalyst; (c) H₂ (excess), Lindlar catalyst; (d) Na,NH₃ ?

Question: A chiral alkyne A with molecular formula C₆H₁₀  is reduced with  and Lindlar catalyst to B having the R configuration at its stereogeniccentre. What are the structures of A and B?

Question: Draw the products of each reaction

a.

b.

Question:What epoxide is formed when each alkene is treated with mCPBA?

a.

b.

c.

Question: Draw all stereoisomers formed when each alkene is treated with mCPBA.

a.

b.

c.

Question: Draw the products formed when both cis- and trans-but-2-ene are treated with a peroxyacid followed by – OH (in H₂O ). Explain how these reactions illustrate that anti-dihydroxylation is stereospecific.

Question: Draw the products formed when both cis- and trans-but-2-ene are treated with OsO₄, followed by hydrolysis with NaHSO₃+H₂O. Explain how these reactions illustrate that syndihydroxylation is stereospecific.

Question: Draw the products formed when each alkene is treated with  O₃ followed by Zn,  H₂O.

a.

b.

c.

Question: What alkene yields each set of oxidative cleavage products?

a. 

b.

Question: Draw the products formed when each diene is treated with O₃ followed by CH₃SCH₃.

a.

b.

c.

Question: Draw the products formed when each alkyne is treated with O₃ followed by H₂O .

a.

b.

c.

Question: What alkyne (or diyne) yields each set of oxidative cleavage products?

a.

b.

c.

d.

Question: Draw the organic products in each of the following reactions.

a. 

b.

c.

d.

Question: What carbonyl compound is formed when each alcohol is treated with HCrO₄––Amberlyst A-26 resin? 

a.

b.

c.

Question: Sodium hypochlorite (NaOCl, the oxidant in household bleach) in aqueous CH₃COOH is also touted as a “green” oxidizing agent. For example, oxidation of (CH₃)₂CHOH  with NaOCl forms along with NaCl and H₂O. (a) What advantages and/or disadvantages does this method have over oxidation with HCrO₄––Amberlyst A-26 resin? (b) What advantages and/or disadvantages does this method have over oxidation with CrO₃, H₂SO_4,H₂O.

Question: Draw the products of each Sharpless epoxidation.

a.

b.

Question:  Explain why only one C=C of geraniol is epoxidized with the Sharpless reagent.

Question: Draw the products formed when A is treated with each reagent: (a) H₂ Pd-C; (b) mCPBA; (c) PCC; (d) CrO₃, H₂SO4, H₂O; (e) Sharpless reagent with (+)-DET.

Question: Draw the products formed when the following diene is treated with  O₃ followed by  H₃CSCH₃ .

Question: Devise a synthesis of the following compound from acetylene and organic compounds containing two carbons or fewer. You may use any other required reagents.

Question: Label each reaction as oxidation, reduction, or neither.

a.

b.

c.

d.

Question: Draw the organic products formed when each alkene is treated with H₂ / Pd-C. Indicate the three-dimensional structure of all stereoisomers formed.

a.

b.

c.

Question: Match each alkene to its heat of hydrogenation.Alkenes: 3-methylbut-1-ene, 2-methylbut-1-ene, 2-methylbut-2-ene $∆\mathrm{H}°$(hydrogenation) kJ/mol: –119, –127, –112

Question: How many rings and π bonds are contained in compounds A–C? Draw one possible structure for each compound. 

a. Compound A has molecular formula  C₅H₈ and is hydrogenated to a compound having molecular formula C₅H₁₀.

b. Compound B has molecular formula C₁₀H₁₆ and is hydrogenated to a compound having molecular formula C₁₀H₁₈  .

c. Compound C has molecular formula C₈H₈ and is hydrogenated to a compound having molecular formula C₈H₁₆.

Question: For alkenes A, B, and C:

Compound A (Monosubstituted)

             Compound B (Tetrasubstituted)

          Compound C (disubstituted)

(a) Rank A, B, and C in order of increasing heat of hydrogenation;

(b) Rank A, B, and C in order of increasing rate of reaction with H₂ Pd-C; (c) Draw the productsformed when each alkene is treated with ozone, followed by Zn-H₂O.

Question: Stearidonic acid (C₁₈H₂₈O₂ ) is an unsaturated fatty acid obtained from oils isolated from hemp and blackcurrant (see also Problem 10.11).

a. What fatty acid is formed when Stearidonic acid is hydrogenated with excess H₂ and a Pd catalyst? 

b. What fatty acids are formed when stearidonic acid is hydrogenated with one equivalent of H₂ and a Pd catalyst?

c. Draw the structure of a possible product formed when stearidonic acid is hydrogenated with one equivalent of H₂  and a Pd catalyst, and one double bond is isomerized to a trans isomer.

d. How do the melting points of the following fatty acids compare: stearidonic acid; one of the products formed in part (b); the product drawn in part (c)?

Draw the organic products formed when cyclopentene is treated with each reagent. With some reagents, no reaction occurs.

a. H₂+Pd-C

b. H₂+ Lindlar catalyst

c. Na ,NH₃

d. CH₃CO₃H

e. [1]. CH₃CO₃H [2] H₂O ,OH^-

f. [1] OSO₄+NMO [2] NaHSO₃, H₂O

g.KMnO₄ ,H₂O ,OH^-

h. [1] LiAlH₄ [2] H₂O

i. [1] O₃ .[2] H₃CSCH₃

j. (CH₃)₃ COOH ,Ti [OCH(CH₃)₃]₄  (-) DET

k. mCPBA

l.Product in (k); Then [1] LiAlH₄ [2] H₂O

Question: Draw the organic products formed when allylic alcohol A is treated with each reagent.

a. H₂ +Pd-c

b. mCPBA 

c. PCC 

d. CrO₃ ,H₂SO₄, H₂O

e.(CH₃)₃COOH , Ti [OCH(CH₃)₃]₄ (+) -DET

f. (CH₃)₃COOH , Ti [OCH(CH₃)₃]₄ (-) -DET 

g. [1] PBr₃ ,[2] LiAlH₄ ,[3] H₂O

h.  HCrO₄^-   –Amberlyst A-26 resin

Question: Draw the organic products formed in each reaction.

a.

b.

c.

d.

Question: One step in the degradation of fats involves the reaction of (R)-glycerol phosphate with NAD⁺  in the presence of the enzyme glycerol phosphate dehydrogenase. What products are formed if reaction occurs only at the 2° alcohol.

Question: Draw the structure of two different epoxides that would yield 2-methylpentan-2-ol [ (CH₃)₂CH(OH)CH₂CH₂CH₃] when reduced with LiAlH₄ .

Question: Hydrogenation of alkene A with D2 in the presence of Pd-C affords a single product B. Keeping this result in mind, what compound is formed when A is treated with each reagent: 

Question: What alkene is needed to synthesize each 1,2-diol using [1]   followed by NAHSO₃  in H₂O ; or [2] CH₃CO₃H  followed by -OH  in H₂O ?

a.

b.

c.

Question: Draw a stepwise mechanism for the reduction of epoxide A to alcohol B using LiAlH₄ . What product would be formed if  LiAlD₄ were used as reagent? Indicate the stereochemistry of all stereogenic centers in the product using wedges and dashed wedges.

Question: a) What product is formed in Step [1] of the following reaction sequence?  

(b) Draw a mechanism for Step [2] that accounts for the observed stereochemistry. 

(c) What reaction conditions are necessary to form chiral A from prop-2-en-1-ol  

Question: Draw the products formed after Steps  and  in the following three-step sequence. Then draw stepwise mechanisms for each step.

Question: Draw the products formed in each oxidative cleavage.

a.

b.

c.

d.

Question: What alkene or alkyne yields each set of products after oxidative cleavage with ozone?

a. 

b.

c.

d.