When an ether is treated with cold concentrated HI, cleavage occurs as follows: Practice

What is wrong with the use of such names as isopropanol and tert-butanol?

Give bond-line formulas and appropriate names for all of the alcohols and ethers with Practice Problem 11.2 the formulas (a) C3H8O and (b) C4H10O.

Predict the major products of the following reactions: Practice Problem 11.3 (a) H2O cat. H2SO4 (c) (2) NaBH4, NaOH (1) Hg(OAc)2, H2O/THF (b) (2) H2O2, NaOH (1) BH3 TH

The following reaction does not produce the product shown. Practice Problem 11.4 H2O cat. H2SO4 OH (a) Predict the major product from the conditions shown above, and write a detailed mechanism for its formation. (b) What reaction conditions would you use to successfully synthesize the product shown above (3,3-dimethyl-2-butanol).

Write equations for the acidbase reactions that would occur (if any) if ethanol were Practice Problem 11.5 added to solutions of each of the following compounds. In each reaction, label the stronger acid, the stronger base, and so forth (consult Table 3.1). (a) NaNH2 (b) H C - Na + (c) ONa O (d) NaOH

Write a detailed mechanism for the following reaction.

(a) What factor explains the observation that tertiary alcohols react with HX faster than Practice Problem 11.7 secondary alcohols? (b) What factor explains the observation that methanol reacts with HX faster than a primary alcohol?

Show how you would prepare the following compounds from the appropriate sulfonyl chlorides. (a) H3C SO3CH3 (b) OSO2Me (c) OSO2Me

Write structures for products X, Y, A, and B, showing stereochemistry. (a) (R)-2-Butanol X Y NaOH (SN2) OH H3C SO2Cl Pyridine (b) A B LiCl Pyridine H3C SO2Cl O

An exception to what we have just said has to do with syntheses of unsymmetrical ethers in which one alkyl group is a tert-butyl group and the other group is primary. For example, this synthesis can be accomplished by adding tert-butyl alcohol to a mixture of the primary alcohol and H2SO4 at room temperature. cat. H2SO4 H2O R OH HO R O Give a likely mechanism for this reaction and explain why it is successful.

(a) Outline two methods for preparing isopropyl methyl ether by a Williamson ether Practice Problem 11.12 synthesis. (b) One method gives a much better yield of the ether than the other. Explain which is the better method and why.

Epoxides can be synthesized by treating halohydrins with aqueous base. Propose a mecha- Practice Problem 11.13 nism for reactions (a) and (b), and explain why no epoxide formation is observed in (c). (a) H2O NaOH HO Cl O (c) H2O NaOH OH Cl No epoxide observed (b) H2O NaOH OH Cl O

Write structures for products A, B, C, and D, showing stereochemistry. (Hint: B and D Practice Problem 11.14 are stereoisomers.) TsCl, pyr K0 K2CO3 (H2) A C D B

Propose mechanisms for the following reactions. (a) Br OH Br O cat. H2SO4 (b) O OH cat. H2SO4

When an ether is treated with cold concentrated HI, cleavage occurs as follows: Practice Problem 11.16 RiOiR + HI 9: ROH + RI When mixed ethers are used, the alcohol and alkyl iodide that form depend on the nature of the alkyl groups. Use mechanisms to explain the following observations:

Write a detailed mechanism for the following reaction. Practice Problem 11.17 O Br HBr (excess) 2

Provide a mechanism for the following reaction. Practice Problem 11.18 OCH3 Cl HCl

Propose structures for each of the following products derived from oxirane (ethylene oxide): Practice Problem 11.19 (a) Methyl Cellosolve C3H8O2 O cat. HA MeOH (b) cat. HA Ethyl Cellosolve C4H10O2 O EtOH (c) C2H5IO O Kl H2O (d) C2H7NO O NH3 (e) C3H8O2 O MeONa MeOH

When sodium ethoxide reacts with 1-(chloromethyl)oxirane (also called epichlorohy- Practice Problem 11.21 drin), labeled with 14C as shown by the asterisk in I, the major product is II. Provide a mechanistic explanation for this result. EtONa I 1-(Chloromethyl)oxirane (epichlorohydrin) II Cl OEt * O * O

Outline a mechanism similar to the one just given that shows how the enantiomeric Practice Problem 11.22 form of trans-1,2-cyclopentanediol is produced.

Supply the missing reagents and intermediates AE. OCH3 HO

Write structures for (a) 15-crown-5 and (b) 12-crown-4.

Give an IUPAC substitutive name for each of the following alcohols:

Write structural formulas for each of the following: (a) (Z)-But-2-en-1-ol (d) 1-Ethylcyclobutanol (g) 2-Ethoxypentane (j) 2-Ethoxyethanol (b) (R)-Butane-1,2,4-triol (e) 2-Chlorohex-3-yn-1-ol (h) Ethyl phenyl ether (c) (1R,2R)-Cyclopentane-1,2-diol (f) Tetrahydrofuran (i) Diisopropyl ether

Provide the alkene needed to synthesize each of the following by oxymercurationdemercuration.

Provide the alkene needed to synthesize each of the following by hydroborationoxidation

Starting with each of the following, outline a practical synthesis of 1-butanol: (a) 1-Butene (b) 1-Chlorobutane (c) 2-Chlorobutane (d) 1-Butyne

Starting with 2-methylpropene (isobutylene) and using any other needed reagents, outline a synthesis of each of the following (T = tritium, D = deuterium):

Show how you might carry out the following transformations:

What compounds would you expect to be formed when each of the following ethers is refluxed with excess concentrated hydrobromic acid?

Considering AL to represent the major products formed in each of the following reactions, provide a structure for each of A through L. If more than one product can reasonably be conceived from a given reaction, include those as well.

Write structures for the products that would be formed under the conditions in Problem 11.34 if cyclopentanol had been used as the starting material. If more than one product can reasonably be conceived from a given reaction, include those as well.

Starting with isobutane, show how each of the following could be synthesized. (You need not repeat the synthesis of a compound prepared in an earlier part of this problem.) (a) tert-Butyl bromide (b) 2-Methylpropene (c) Isobutyl bromide (d) Isobutyl iodide (e) Isobutyl alcohol (two ways) (f) tert-Butyl bromide

Outlined below is a synthesis of the gypsy moth sex attractant disparlure (a pheromone). Give the structure of disparlure and intermediates AD. HC i CNa 9999999: 1@bromo@5@methylhexane liq. NH3 A (C9H16) 99: NaNH2 liq. NH3 B (C9H15Na) 9999: 1-bromodecane C (C19H36) 999: H2 Ni2B(P@2) D (C19H38) 999: mCPBA Disparlure (C19H38O)

Provide the reagents necessary for the following syntheses. More than one step may be required.

Predict the major product from each of the following reactions

rovide the reagents necessary to accomplish the following syntheses.

Provide reagents that would accomplish the follwing syntheses.

Write structures for compounds AJ showing stereochemistry where appropriate. (a) A C B D (2) H2O2, HO (1) BH3 THF TsCl, pyr KOH KI $ What is the stereochemical relationship between A and C? (b) OH E F pyr MsCl HC CNa (c) OH G NaH H MeI I MsCl pyr J MeONa What is the stereochemical relationship between H and J?

Write a mechanism that accounts for the following reaction:

Propose a reasonable mechanism for the following reaction.

Propose a reasonable mechanism for the following reaction.

Propose a reasonable mechanism for the following reaction

Vicinal halo alcohols (halohydrins) can be synthesized by treating epoxides with HX. (a) Show how you would use this method to synthesize 2-chlorocyclopentanol from cyclopentene. (b) Would you expect the product to be cis-2-chlorocyclopentanol or trans-2- chlorocyclopentanol; that is, would you expect a net syn addition or a net anti addition of iCl and iOH? Explain.

Base-catalyzed hydrolysis of the 1,2-chlorohydrin 1 is found to give a chiral glycol 2 with retention of configuration. Propose a reasonable mechanism that would account for this transformation. Include all formal charges and arrows showing the movement of electrons.

While simple alcohols yield alkenes on reaction with dehydrating acids, diols form carbonyl compounds. Rationalize mechanistically the outcome of the following reaction:

When the bicyclic alkene I, a trans-decalin derivative, reacts with a peroxy acid, II is the major product. What factor favors the formation of II in preference to III? (You may find it helpful to build a handheld molecular model.)

Use Newman projection formulas for ethylene glycol (1,2-ethanediol) and butane to explain why the gauche conformer of ethylene glycol is expected to contribute more to its ensemble of conformers than would the gauche conformer of butane to its respective set of conformers.

When the 3-bromo-2-butanol with the stereochemical structure A is treated with concentrated HBr, it yields meso-2,3- dibromobutane; a similar reaction of the 3-bromo-2-butanol B yields ({)-2,3-dibromobutane. This classic experiment performed in 1939 by S. Winstein and H. J. Lucas was the starting point for a series of investigations of what are called neighboring group effects. Propose mechanisms that will account for the stereochemistry of these reactions.

Reaction of an alcohol with thionyl chloride in the presence of a tertiary amine (e.g., pyridine) affords replacement of the OH group by Cl with inversion of configuration (Section 11.9). However, if the amine is omitted, the result is usually replacement with retention of configuration. The same chlorosulfite intermediate is involved in both cases. Suggest a mechanism by which this intermediate can give the chlorinated product without inversion.

Draw all of the stereoisomers that are possible for 1,2,3-cyclopentanetriol. Label their chirality centers and say which are enantiomers and which are diastereomers. HO OH OH (Hint: Some of the isomers contain a pseudoasymmetric center, one that has two possible configurations, each affording a different stereoisomer, each of which is identical to its mirror image. Such stereoisomers can only be distinguished by the order of attachment of R versus S groups at the pseudoasymmetric center. Of these the R group is given higher priority than the S, and this permits assignment of configuration as r or s, lowercase letters being used to designate the pseudoasymmetry.)

Dimethyldioxirane (DMDO), whose structure is shown below, is another reagent commonly used for alkene epoxidation. Write a mechanism for the epoxidation of (Z)-2-butene by DMDO, including a possible transition state structure. What is the by-product of a DMDO epoxidation?

Two configurations can actually be envisioned for the transition state in the DMDO epoxidation of (Z)-2-butene, based on analogy with geometric possibilities fitting within the general outline for the transition state in a peroxycarboxylic acid epoxidation of (Z)-2-butene. Draw these geometries for the DMDO epoxidation of (Z)-2-butene. Then, open the molecular models on the books website for these two possible transition state geometries in the DMDO epoxidation of (Z)-2-butene and speculate as to which transition state would be lower in energy

Devise two syntheses for meso-2,3-butanediol starting with acetylene (ethyne) and methane. Your two pathways should take different approaches during the course of the reactions for controlling the origin of the stereochemistry required in the product.

(a) Write as many chemically reasonable syntheses as you can think of for ethyl 2-methylpropyl ether (ethyl isobutyl ether). Be sure that at some point in one or more of your syntheses you utilize the following reagents (not all in the same synthesis, however): PBr3, SOCl2, p-toluenesulfonyl chloride (tosyl chloride), NaH, ethanol, 2-methyl-1-propanol (isobutyl alcohol), concentrated H2SO4, Hg(OAc)2, ethene (ethylene). (b) Evaluate the relative merits of your syntheses on the basis of selectivity and efficiency. (Decide which ones could be argued to be the best syntheses and which might be poorer syntheses.)

Synthesize the compound shown below from methylcyclopentane and 2-methylpropane using those compounds as the source of the carbon atoms and any other reagents necessary. Synthetic tools you might need include Markovnikov or anti-Markovnikov hydration, Markovnikov or anti-Markovnikov hydrobromination, radical halogenation, elimination, and nucleophilic substitution reactions.