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CH 237 Exam 1 Study online at quizlet.com/_2z2ye h 1.

Are alcohols important biologically?

Yes

2.

Overall, what is the difference between alcohols ad alkanes? (2)

1. Alcohols have higher boiling points 2. Alcohols are more water soluble

3.

4.

Why do alcohols have higher boiling points and are more soluble compared to alkanes?

Because of their ability to hydrogen bond with themselves and water

What does the carbon on an It is partially positive and alcohol act as? electron poor What kind of alcohol is glycerol?

1°, 2° alcohol

6.

What kind of alcohol is glucose?

1°, 2° alcohol

7.

What kind of alcohol is testosterone?

2° alcohol

8.

What kind of alcohol is norethindrone?

3° alcohol

9.

What are the steps for naming alcohols? (6)

1. Find the longest continuous chain that contains the OH group 2. Take the parent alkane name, drop the -e and add -ol 3. Number the parent chain so that the carbon with the OH group gets the lowest location number 4. Name all substituents just as with alkanes 5. Alphabetical listing of substituents still applies 6. The OH group takes priority over alkenes, alkynes, and halides

5.

10.

What type of pKa's do ordinary alcohols have?

Their pKa's are similar to water

11.

In order to remove a hydrogen from an alcohol, what is needed?

A good base such as Na, K, or NaNH2 must be used

12.

What are the five ways to make an alcohol?

1. Hydroboration 2. Oxymercuration 3. Halohydrin 4. Hydration 5. Osmium

13.

Describe hydroboration: (3)

1. Anti-markovnikov 2. No rearrangement 3. Syn addition

14.

Describe oxymercuration: (3)

1. Markovnikov 2. No rearrangement 3. Anti addition

15.

Describe halohydrin:

Markovnikov

16.

Describe hydration (H+/H2O): (2)

1. Markovnikov 2. Cation rearrangement

17.

Describe osmium (OsO4):

Syn addition

18.

When does the reaction of alcohol with HX work really well?

If there is an alcohol that leaves a stable cation

19.

When does the reaction of alcohol with HX not work well?

It doesn't work well with primary and secondary carbons

20.

When will cations rearrange?

Anytime there is a cation intermediate

21.

How do secondary, tertiary, allylic, and benxylic alcohols react with HBr or HCl?

Through an SN1 mechanism

22.

How do primary and methyl alcohols react with HBr and HCl?

Through an SN2 mechanism

23.

What are the limitations to the reactions of alcohols with HX? (4)

1. Most alcohols do not react with HI to give good yields and alkyl iodide 2. Primary and secondary alcohols react very slowly with HCl resulting in poor yields 3. Elimination is always a possible side reaction when heating an alcohol in the presence of acid 4. Rearrangements are always possible when cations are the intermediates

24.

What happens with rearrangements with HBr and 2° alcohols?

The carbocation will rearrange, usually with a hydride shift

25.

How can rearrangement be prevented?

By using PBr3 and SOCl2

26.

Will the reaction of alcohols with PBr3 and SOCl2 work with tertiary alcohols?

No, due to steric hindrance

27.

What type of conditions are Milder conditions than those required with the reaction of for HBr or HCl with alcohols alcohols wtih PBr3 and SOCl2?

28.

What type of alcohols work well with PBr3 and SOCl2?

1° and 2° alcohols

29.

What is the mechanism for alcohols with PBr3 and SOCl2?

SN2

30.

What happens in the reaction of alcohols with PBr3 and SOCl2?

Inversion of stereochemistry

31.

What are the drawbacks from going directly from the alcohol to alkyl halide?

Many nucleophiles cannot survive in an acidic solution

49.

What functional groups can be reduced to form alcohols? (2)

1. Aldehydes 2. Ketones

32.

Why are alcohols converted to their corresponding ester in turning alcohols into alkyl halides?

Because most nucleophiles cannot survive in an acidic solution

50.

Can alcohols be oxidized to form aldehydes and ketones?

Yes

51.

33.

What is the reaction of turning an alcohol into its corresponding base?

It is done in the presence of p-Toluenesulfonyl chloride and a base

When a primary alcohol 1. Aldehydes is oxidized, what do they 2. Carboxylic acids form? (2)

52.

Describe a tosylate group: (3)

1. Good leaving group 2. Can be isolated 3. Stable on its own

When a secondary alcohol is oxidized, what do they form?

Ketones

34.

53.

What types of alcohols are used to prepare alkyl tosylates?

1° or unhindered 2° alcohols are used

36.

Why is a mild base used in the reaction?

To absorb the HCl generated during the reaction (often pyridine)

Can tertiary alcohols be oxidized without breaking bonds and destroying the molecule?

No

35.

54.

Through a chromate ester

What does pyridine do?

Encourages the hydrogen to leave and bond with chlorine, producing a salt (HCl)

How does the mechanism of chromate oxidation occur?

55.

What is the color of From dark orange to green chromium 6 and what color does it turn when it is oxidized to chromium 3?

56.

Describe the elimination of a chromate ester:

The alkyl chromate reactions with a base, in this case water, which results in a C—H bond breaking

37.

38.

Besides pyridine, what chemicals can also be used? (3)

1. CN2. I3. N3-

39.

What is the reaction between tosylate and a nucleophile?

SN2

40.

What happens to a chiral center during the reaction of tosylate and a nucleophile?

Inversion

57.

What is an alternative to the chromate ester oxidation?

Swern oxidation

41.

Why is tosylate a good leaving group?

Due to resonance

58.

What does pyridinium chloromate (PCC) do?

Will only oxidize a 1° alcohol to aldehyde, not a carboxylic acid

42.

What is the reaction of the dehydration of alcohols with acid?

E1

59.

Why is PCC used instead Because chromic acid attacks of chromic acid? C=C

60.

43.

What alcohols can be dehydrated with acid?

3° or 2° alcohol

Describe the pinacol rearrangement:

44.

When dehydrating alcohols with acid, what is the reaction carried out with?

With either 85% H3PO4 or concentrated H2SO4

1. Oxidation of a molecule containing two —OH groups 2. Contains a 3° cation that rearranges, there is a methyl shift

61.

45.

What is the alcohol reactivity in dehydrating them with acid?

3° > 2° > 1°

Why does rearrangement occur in pinacol rearrangement?

The pair of electrons on oxygen create a resonance structure which causes an intermediate, making all the molecules have an octet

46.

Describe 1° alcohol dehydration Require high temperature, with acid: give poor yields, and rearrangement is common

62.

What is the product of pinacol rearrangement?

Ketone

Describe 2° alcohol dehydration with acid:

Require lower temperature and rearrangement may or may not occur

63.

47.

What can vicinal or 1,2diols be cleaved under oxidative conditions to yield? (2)

1. Aldehydes 2. Ketones

Describe 3° alcohol dehydration with acid:

May eliminate at room temperature and rearrangement is highly uncommon

64.

In 1,2-diol cleavage, what is the oxidizing agent

Periodic acid HIO4

48.

65.

In order for 1,2-diol cleavage to occur, how must the two -OH groups be arranged?

They must be on the same molecule (cis)

66.

What is the only bond that breaks in 1,2-diol cleavage?

The bond between the two -OH groups because all of the electrons move at the same time

67.

What compounds can be used to form new C-C bonds? (3)

1. Organomagnesium 2. Organolithium 3. Diorganocopper

68.

Why can organomagnesium, organolithium, and lithium diorganocopper be used to form new C-C bonds? (2)

1. They all behave as nucleophiles or are nucleophile-like 2. All three types are extremely reactive toward electrophiles and are sensitive to water

78.

What groups can Grignard reactants not interact with? (6)

1. RC ≡ CH 2. RNH2 3. RCOOH 4. RSH 5. ROH 6. H2O

79.

How do Grignard reagents react with formaldehyde?

They form primary alcohols

80.

How do Grignard reagents react with aldehydes?

They form secondary alcohols

81.

How do Grignard reagents react with ketones?

They form tertiary alcohols

82.

How do Grignard reagents react with esters?

They form tertiary alcohols

83.

How do Grignard reagents react with CO2?

They form acids

84.

How do Grignard reagents react with epoxides?

They form primary alcohols

85.

What do epoxides do with Grignard reagents? (3)

1. They are reactive and can pop open, mostly with nucleophiles due to the polarity of oxygen 2. Because of the ring strain, they react with a variety of nucleophiles including Grignard reagents 3. This reaction not only creates a new C-C bond, but also add an OH group to the molecule

69.

How are Grignard reagents prepared?

By reacting an alkyl, aryl, or alkenyl halide with magnesium metal in either diethyl ether or tetrahydrofuran (THF)

70.

What are some problems with Grignard reagents?

1. Not good at coupling (will not react with alkane reactants) 2. Don't dissolve salts 3. Once they interact with water they become inactive

86.

What are epoxides?

What does the ether do to a Grignard reagent?

It protects it during a reaction

Three-member rings consisting of an oxygen and two carbons

87.

SN2 reaction

How does a Grignard reaction take place?

The reactions are run in the absence of water and under either N2 or Ar gas.

What type of reaction happens between a Grignard reactant and an epoxide?

88.

What do epoxides add to a Extra carbons and make molecule? alcohols

89.

What is a Gillman reagent? 1. Nucleophile like because it (3) doesn't form a negative charge on a carbon 2. Attack C-H bonds 3. Must contain C-X

71.

72.

What is the change in oxidation state of the metal when magnesium reacts with an alkyl bromide to give an alkyl magnesium bromide (Grignard reagent)?

0 to +2

74.

In Grignard reagents, what is the alkyl metal bond?

It is very polar

90.

Can water stop a Gillman reagent?

Yes

75.

What ionic character does the CMg bond have?

35%

91.

76.

Is the Grignard reagent a good nucleophile?

Yes because it is very polar

What are some commonalities between Grignard, organolithium, and Gilman? (3)

1. All contain metals 2. All or nucleophiles or nucleophile-like (Gilman) 3. All form new C-C bonds

77.

Because Grignard reagents are extremely basic, what must happen?

The reactions must be carried out in the absence of water or acidic hydrogens

92.

What is the easiest way to make a three membered carbon ring? (2)

1. Simmons-Smith Reaction 2. Alpha Elimination

73.

93.

What are carbenes? 1. Reactive species where the carbon (2) has two bonds and two unpaired electrons 2. A carbon that doesn't have all the electrons, it's neutral and can act as a nucleophile

94.

What is stereospecific?

The stereospecifity depends on one of the reactants

95.

Can carbenes be treated as electrophile?

Yes and can add to C=C in a concerted fashion

96.

In carbene addition, Stereochemistry stereochemistry at the ______ is maintained after addition

97.

How can carbene addition occur? (2)

1. Simmons-Smith Reaction 2. Alpha Elimination

98.

What happens in Simmons-Smith?

Generates a carbenoid, not a carbene, products include ZnI2 and an ethylene carbene

99.

What are aldehydes?

Have one alkyl or aryl group attached to the carbonyl carbon

100.

What are ketones?

Have two alkyl or aryl groups attached to the carbonyl carbon

101.

What do many steroids contain?

A carbonyl along with other functional groups

102.

In naming, what gets priority over everything else?

Carbonyl carbons

103.

What are the ways to make aldehydes or ketones?

1. Hydroboration 2. Oxymercuration 3. Ozonolysis

104.

Are aldehydes more reactive than ketones?

Yes, because aldehydes are less hindered and more electron poor which makes it easier for a nucleophile to attack and react with the carbonyl group

What are the two mechanisms for a nculeophile attack on carbonyl groups? (2)

1. When the reagent is a strong nucleophile, OH-,H-,R3C-, RO-, or NC2. When the nucleophile is neutral or weak, HOH, ROH, NH3, RNH2, the reaction requires an acid catalyst

105.

106.

Describe the formation of primary alcohols from formaldehyde:

1. Addition of any Grignard reagent to formaldehyde yields a 1° alcohol 2. Strong nucleophile 3. Grignard is good at reacting with a carbonyl group 4. SN2 like reaction

107.

Describe the formation 1. Addition of any Grignard reagent of secondary alcohols to any aldehyde other that from aldehydes: (2) formaldehyde yields a 2. 2° alcohol Example: bromobenzene

108.

Describe the formation Addition of any Grignard reagent of tertiary alcohols to any ketone yields a 3° alcohol from ketones:

109.

Describe the nucleophilic addition of -CN: (2)

1. Linamarin and Amygdalin are two naturally occurring cyanohydrin derivatives. 2. Both compounds are toxic because they are metabolized to cyanohydrins, which are hydrolyzed to carbonyl compounds and HCN gas

110.

What do wittig reagents react readily with?

1. Aldehydes 2. Ketones

111.

How do sterically hindered ketones react with wittig reagents?

They react slowly and give poor yields

112.

What can wittig carbonyl carbons contain? (4)

1. OH 2. OR 3. Aromatic nitro 4. Ester groups

113.

What are wittig reagents best formed from? (2)

1. 1° allylic halides 2. 2°allylic halides

114.

What type of alkynes can be synthesized with wittig reagents? (3)

1. Mono-substituted alkenes 2. Di-substituted alkenes 3. Tri-substituted alkenes

115.

What type of stereochemistry do wittig products have?

Alkene products can be a mixture of E and Z stereochemistry

116.

______ stereochemistry can be favored by stabilized Wittig reagents

E

117.

Do wittig reactions always follow zaitsev's rule?

No

118.

What is an alternative method to the Wittig reaction?

HEW reaction

119.

Ketones which are unreactive toward ______ reagents can be used with HEW

Wittig

120.

In HEW reaction, the __________ reacts to form α,β-unsaturated aldehyde, ketone, or ester

phosphonoester

121.

What isomer is formed exclusively in the HEW reaction?

E isomer

138.

Why do acetals make good protecting groups in synthesis?

Because they are easily removed

122.

What do oxygen and nitrogen-containing nucleophiles react readily with? (2)

1. Aldehydes 2. Ketones

139.

What is used with acetals reacting with Grignard reagents to control entropy?

Ethylene glycol

123.

Water adds to carbonyls to form _______

Hydrates

140.

What is another name for imines?

Schiff bases

124.

Describe hydrates: (4)

1. Unstable 2. Hard to isolate 3. Reversible reactions 4. Stable hydrates are ones with withdrawing groups on a neighboring carbon

141.

What are imines formed from? (2)

1. Primary amine 2. Aldehyde or ketone

142.

Is the imine reaction reversible?

Yes

143.

What must the imine reaction take place in the presence of?

An acid catalyst (pH = 4.5)

144.

What is the reaction of imines driven by? (2)

1. Precipitation of the product 2. Removal of water

145.

What double bond does an imine contain?

Double bond between nitrogen and carbon

146.

What are enamines formed from? (2)

1. Secondary amines 2. Aldehydes or ketones

147.

the mechanism for the formation of ______ is identical to imines until the next to the last step

Enamines

125.

Alcohols add to carbonyls to form ______

Acetals

126.

Describe acetals: (4)

1. Protecting groups 2. Can be produced by acids or bases 3. Final product is diethyl acetal 4. If mixed with acid and water it will go back to starting product

127.

Primary amines add to carbonyls to form ______

Imines

128.

Secondary amines add to carbonyls to form ________

Enamines

148.

What happens in the mechanism for imines?

The protonated nitrogen looses H+ ...