The reaction of an alkene with diazomethane forms a cylcopropane ring. Propose a

What is the major product of each of the following reactions? a. CH2CH3 CH2 b. CH2 CCH2CH3 HBr HBr CH3 c. CH d. CH3CH2CCH HBr

Identify the electrophile and the nucleophile in each of the following reaction steps, and then draw curved arrows to illustrate the bond-making and bond-breaking processes. a. b. CH3CH CH2 c. CH3CHCH3 Cl CH3CHCH3 Cl CH3CH CH3 Br CH3CH CH2 BH3 CH3CH2 CH2BH2

What will be the major product of the reaction of 2-methyl-2-butene with each of the following reagents? a. HBr b. HI c. Cl 2 >CH 2 Cl 2 d. O 3 , 78 C, followed by (CH 3 )2S e. H 2 >Pd f. MCPBA (a peroxyacid) g. H2O + traceH2SO4 h. Br 2 /CH 2 Cl 2 i. Br 2 >H 2 O j. Br 2 >CH 3 OH k. BH3>THF, followed by H2O2, HO-, H2O

Give two names for each of the following: a. b. CHCHCH3 CH O 3CH2 CH3CH2 CH3 C CHCH2CH3

a. Which is the most stable: 3,4-dimethyl-2-hexene, 2,3-dimethyl-2-hexene, or 4,5-dimethyl-2-hexene? b. Which compound would you expect to have the largest heat of hydrogenation? c. Which compound would you expect to have the smallest heat of hydrogenation?

What reagents are needed to synthesize the following alcohols? OH O

Identify each of the following reactions as an oxidation reaction, a reduction reaction, or neither. Cl Cl CH3CH Cl CHCH3 + 2 CH3CHCHCH3 OH CH3CH H CHCH3 + 2O CH3CHCH2CH3 H2SO4

What are the products of the following reactions? Indicate whether each reaction is an oxidation or a reduction. a. CH3CH2C CHCH2CH3 1. O3, 78 C 2. Zn, CH3CO2H CH3 b. CH3CHCH CHCH3 CH3 H2 Pd/C c. CH3 2. (CH3)2S 1. O3, 78 C

When 3-methyl-1-butene reacts with HBr, two alkyl halides are formed: 2-bromo-3-methylbutane and 2-bromo-2-methylbutane. Propose a mechanism that explains the formation of these two products.

Problem 40 in Chapter 5 asked you to d raw the structures for all the alkenes with molecular formula C6H12. Use those structures to answer the following questions: a. Which of the compounds is the most stable? b. Which of the compounds is the least stable?

Draw curved arrows to show the fl ow of electrons responsible for the conversion of the following reactants into products. a. b. CH3C C + + c. CH3CH2 + CH3 Br CH3CH2 C OCH3 O CH3 CH3 CH3 C O CH3O H CH3C C + NH3 Br CH3O OCH3 + NH2

What reagents are needed to carry out the following syntheses? O Br Br OH OCH3 Br OH OH Br O H

What is the major product of each of the following reactions? HCl a. Br2 CH3OH b. RCOOH O c. d. H2SO4 H2O e. f. Cl2 H2O g. H2SO4 CH3OH h. Cl2 CH2Cl2 1. O3, 78C 2. (CH3)2S

Using any alkene and any other reagents, how would you prepare the following compounds? a. c. CH2OH e. CH2CHCH3 OH b. CH3CH2CH2CHCH3 Cl d. CH3CH2CHCHCH2CH3 Br OH f. CH3CH2CHCHCH2CH3 Br Cl

a. Identify two alkenes that react with HBr to form 1-bromo-1-methylcyclohexane without undergoing a carbocation rearrangement. b. Would both alkenes form the same alkyl halide if DBr were used instead of HBr? (D is an isotope of H, so D+ reacts like H+ .)

Which is more stable? a. CH3CCH3 or CH3CHCH2CH3 CH3 + + or or c. d. + + e. CH3C CHCH2CH3 or CH3CH CH3 CH3 CHCHCH3 b. CH3CHCH3 or CH3CHCH2Cl + + f. CH3 or CH3

a. Draw the product or products that would be obtained from the reaction of cis -2-butene and trans -2-butene with each of the following reagents. If a product can exist as stereoisomers, show which stereoisomers are formed. 1. HCl 4. Br 2 in CH 2 Cl 2 7. H2O + H2SO4 2. BH 3 /THF followed by HO- , H 2 O 2 , H 2 O 5. Br2 + H2O 8. CH3OH + H2SO4 3. a peroxyacid 6. H2 + Pd/C b. With which reagents do the two alkenes react to form different products?

The second-order rate constant (in units of M-1 s-1 ) for acid-catalyzed hydration at 25 C is given for each of the following alkenes: CH2 4.95 x 108 8.32 x 108 3.51 x 108 2.15 x 104 3.42 x 104 H3C H C H3C H3C CH3 CH3 C C H3C H CH3 CH3 C C H3C H H CH3 C C H3C H CH3 H C C a. Calculate the relative rates of hydration of the alkenes. ( Hint: Divide each rate constant by the smallest rate constant of the series: 3.51 * 10-8 .) b. Why does ( Z )-2-butene react faster than ( E )-2-butene? c. Why does 2-methyl-2-butene react faster than ( Z )-2-butene? d. Why does 2,3-dimethyl-2-butene react faster than 2-methyl-2-butene?

Which compound has the greater dipole moment? a. or H H H Cl C C Cl H H Cl C C b. or Cl H CH3 H C C Cl H H CH3 C C

Draw the products of the following reactions. If the products can exist as stereoisomers, show which stereoisomers are formed. a. CH3 CH2CH3 Br2 CH2Cl2 c. Br2 CH2Cl2 CH3 CH3 b. CH3CH2CH2CH CH2 + H2O H2SO4 d. HBr

A student was about to turn in the products he had obtained from the reaction of HI with 3,3,3-trifl uoropropene when he realized that the labels had fallen off his fl asks and he did not know which label belonged to which fl ask. His friend reminded him of the rule that says the electrophile adds to the sp2 carbon bonded to the most hydrogens. In other words, he should label the fl ask containing the most product 1,1,1-trifl uoro-2-iodopropane and label the fl ask containing the least amount of product 1,1,1-trifl uoro3- iodopropane. Should he follow his friends advice?

a. Propose a mechanism for the following reaction (show all curved arrows): H2SO4 CH3CH2CH CH2 + CH3OH CH3CH2CHCH3 OCH3 b. Which step is the rate-determining step? e. What is the electrophile in the second step? c. What is the electrophile in the fi rst step? f. What is the nucleophile in the second step? d. What is the nucleophile in the fi rst step?

Draw the products, including their confi gurations, obtained from the reaction of 1-ethylcyclohexene with the following reagents: a. HBr b. H 2 , Pd/C c. R 2 BH/THF followed by HO , H 2 O 2 , H 2 O d. Br 2 /CH 2 Cl 2

Which stereoisomer of 3-hexene forms a meso compound when it reacts with Br 2 ?

Which stereoisomer of 3-hexene forms (3 S ,4 S )-4-bromo-3-hexanol and (3 R ,4 R )-4-bromo-3-hexanol when it reacts with Br 2 and H 2 O?

Propose a mechanism for each of the following reactions: + + Cl

What is the major product of each of the following reactions? CH2Cl2 CH2Cl2 a. HOCH b. 2CH2CH2CH CH2 Br + 2 HOCH2CH2CH2CH2CH CH2 Br + 2

Draw the products of the following reactions. If the products can exist as stereoisomers, show which stereoisomers are formed. a. cis -2-pentene + HCl f. 1,2-dideuteriocyclohexene + H 2 , Pd/C b. trans -2-pentene + HCl g. 3,3-dimethyl-1-pentene + Br 2 /CH 2 Cl 2 c. 1-ethylcyclohexene + H 2 O + H 2 SO 4 h. 1E2@3,4@dimethyl@3@heptene + H2, Pd/C d. 2,3-dimethyl-3-hexene + H 2 , Pd/C i. 1Z2@3,4@dimethyl@3@heptene + H2, Pd/C e. 1,2-dimethylcyclohexene + HCl j. 1@chloro@2@ethylcyclohexene + H2, Pd/C

a. What product is obtained from the reaction of HCl with 1-butene? With 2-butene? b. Which of the two reactions has the greater free energy of activation? c. Which compound reacts more rapidly with HCl, ( Z )-2-butene or ( E )-2-butene?

What would be the major product of the reaction of each of the following with HBr?

For each compound, show the products obtained from ozonolysis, followed by treatment with dimethyl sulfi de.

Which stereoisomer of 3,4-dimethyl-3-hexene forms (3 S ,4 S )-3,4-dimethylhexane and (3 R ,4 R )-3,4-dimethylhexane when it reacts with H 2 , Pd/C?

a. How many alkenes could you treat with H 2 , Pd/C in order to prepare methylcyclopentane? b. Which of the alkenes is the most stable? c. Which of the alkenes has the smallest heat of hydrogenation?

Draw the products of the following reactions. If the products can exist as stereoisomers, show what stereoisomers are formed. a. cis@2@pentene + Br2>CH2Cl2 b. trans@2@pentene + Br2>CH2Cl2 c. 1@butene + HCl d. methylcyclohexene + HBr e. trans@3@hexene + Br2>CH2Cl2 f. cis@3@hexene + Br2>CH2Cl2 g. 3,3@dimethyl@1@pentene + HBr h. cis@2@butene + HBr i. 1Z2@2,3@dichloro@2@butene + H2, Pd/C j. 1E2@2,3@dichloro@2@butene + H2, Pd/C k. 1Z2@3,4@dimethyl@3@hexene + H2, Pd/C l. 1E2@3,4@dimethyl@3@hexene + H2, Pd/C

the possible products shown for the following reaction, are there any that would not be formed? + HCl CH2CH CH2 H Br CH3 CH3 CH3 Br H H Cl CH3 CH3 H Br H Cl CH3 CH3 H Br Cl H H H H H H H

The reaction of an alkene with diazomethane forms a cylcopropane ring. Propose a mechanism for the reaction. ( Hint: It is a concerted reaction.) CH2 N N + 2 diazomethane N + CH2 CH2 + Note: Diazomethane is a gas that must be handled with great care because it is both explosive and toxic.

Two chemists at Dupont found that ICH 2 ZnI is better than diazomethane at converting a CC bond to a cylcopropane ring. Propose a mechanism for the reaction, now known as the SimmonsSmith reaction in their honor.

a. Dichlorocarbene can be generated by heating chloroform with HO- . Propose a mechanism for the reaction. HO + chloroform dichlorocarbene CHCl3 + H2O Cl2C Cl + b. Dichlorocarbene can also be generated by heating sodium trichloroacetate. Propose a mechanism for the reaction. Cl2C sodium trichloroacetate

What product would be obtained from the reaction of dichlorocarbene with cyclopentene?

What alkene gives the product shown after reaction fi rst with ozone and then with dimethyl sulfi de O O O O b. H H O C O C

Draw the products of the following reactions including their confi gurations: H CH3 H3C CH(CH3)2 HBr H2 Pd/C Br2, CH3OH H2O, H2SO4 Br2, CH2Cl2 Br2, H2O 1. BH3/THF C C 2. H2O2, HO

a. Propose a mechanism for the following reaction: Br HBr Br + + b. Is the initially formed carbocation primary, secondary, or tertiary? c. Is the rearranged carbocation primary, secondary, or tertiary? d. Why does the rearrangement occur?

Which compound would you expect to be hydrated more rapidly? CH3C CH2 CH3 ClCH2C CH2 CH3

When the following compound is hydrated in the presence of acid, the unreacted alkene is found to have retained the deuterium atoms. What does this tell you about the mechanism for hydration? CH CD2

When fumarate reacts with D 2 O in the presence of the enzyme fumarase, only one isomer of the product is formed, as shown here. Is the enzyme catalyzing a syn or an anti addition of D 2 O? + D2O OOC H fumarate COO fumarase COO COO DO H D H H C C

When ( S )-(+)-1-chloro-2-methylbutane reacts with chlorine, one of the products is ()-1,4-dichloro-2-methylbutane. Does this product have the R or the S confi guration?

Propose a mechanism for the following reaction: H2O HO + H2SO4 H3C CH3 CH3 CH CH2

What hydrocarbon would form the following products after reaction fi rst with ozone and then with dimethyl sulfi de? + O O O H H O O H H + O H H

Ozonolysis of an alkene, followed by treatment with dimethyl sulfi de, forms the following product(s). Identify the alkene in each case. a. O O O O H b. O H O O O + H H