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CH223 > CH223 Part 3/4: Organometallic & Aldehydes/Ketones (Conceptual) > Flashcards

CH223 Part 3/4: Organometallic & Aldehydes/Ketones (Conceptual) Flashcards

1
Q

What do weakly activating substituents direct to?

A

ortho and para

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2
Q

What do strongly activating substituents direct to?

A

ortho and para

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3
Q

Who do weakly deactivating substituents direct to?

A

ortho para

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4
Q

What do strongly deactivating substituents direct to?

A

meta

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5
Q

What are some weakly deactivating substituents?

A

F, Cl, Br, I

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6
Q

What are some strongly activating substituents?

A

EDG

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7
Q

What substituent controls regioselectivity?

A

the most activating one

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8
Q

Where does substitution occur when positions are comparatively activated?

A

the less hindered site

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9
Q

What should you use when you have an ortho, para director but only want ortho?

A

SO3H blocking group

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10
Q

How are primary alkyl groups more efficiently introduced?

A

freidel-crafts acylation

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11
Q

Why are aryl halides less reactive than alkyl halides?

A
  • carbon halogen bonds are stronger
  • the backside attack is blocked
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12
Q

What are exceptions that allow NAS to occuer?

A

the presence of a strong electronegative substituent

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13
Q

What position(s) will NOT react in a NAS reaction?

A

meta

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14
Q

Compare the reactivity of the halogens in an NAS reaction

A

X=F > X=Cl > X=Br > X=I

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15
Q

Why are X=F more reactive than X=I in an NAS reaction?

A

the most electronegative atom better stabilizes the negative charge on the intermediate

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16
Q

What are organometallic compounds?

A

compounds that have a carbon-metal bond

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17
Q

Which way are electrons pulled when carbon is bound to a metal?

A

towards the carbon

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18
Q

Compare the rates of reaction of Grignard reagents?

A

R-I > R-BR > R-Cl > R-F > alkene > alkyne

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19
Q

Organometallic compounds are prepared in which solvent?

A

aprotic solvents

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20
Q

Why do organometallic compounds have to be prepared in aprotic solvents?

A

they are extremely basic’ will deprotonate any slightly acidic molecule

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21
Q

What functional groups can Grignard reagents not be used in the presence of?

A

NH, OH, and SH

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22
Q

What product does an aldehyde reaction with an organometallic reagent give?

A

secondary alcohol

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23
Q

What product does an ketone reaction with an organometallic reagent give?

A

tertiary alcohol

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24
Q

What product does a formaldehyde reaction with an organometallic reagent give?

A

primary alcohol

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25
Q

What are the most acidic hydrocarbons?

A

alkynes

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26
Q

What does it mean for something to act catalytically?

A

for as little as 1 mol % to be used

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27
Q

Which reaction is extremely efficient and tolerant of various functional groups?

A

palladium-catalyzed cross-couplings

28
Q

What leaving group can be used in a Pd. catalyzed reaction?

A

aryl/vinyl (sp2) halides or OTf

29
Q

What are the four steps of a Suzuki mechanism?

A

1) Oxidative Addition
2) Ligand Exchange
3) Transmetallation
4) Reductive Elimination

30
Q

What happens during oxidative addition?

A

two groups are added to a metal

31
Q

What happens during ligand exchange?

A

hydroxide attacks Pd and kicks out X

32
Q

What happens during transmetallation?

A

other carbon attacks palladium, breaking bond between OH and Pd

33
Q

What happens during reductive elimination?

A

the two Pd groups are removed from the metal

34
Q

What are the three steps to the Heck mechanism?

A

1) Oxidative Addition
2) Migratory Insertion
3) Beta-hydride Elimination

35
Q

Which Pd. catalyzed reaction should you use if you want a trans product?

A

Heck

36
Q

What happens to the cis and trans conformation during a Pd. catalyzed reaction?

A

the conformation is retained

37
Q

Do aldehydes/ketones or alcohols have priority?

A

aldehydes/ketones

38
Q

Do aldehydes/ketones or halogens have priority?

A

aldehydes/ketones

39
Q

Do aldehydes or ketones have priority?

A

aldehydes

40
Q

What group do aldehydes contain?

A

formyl group

41
Q

How are aldehydes names?

A

by replacing the -e with -al

42
Q

How are ketones names?

A

by replacing -e with -one

43
Q

What orbital do electrophiles react with?

A

LUMO

44
Q

The presence of water in Cr-based oxidations leads to what?

A

the formation of a carboxylic acid

45
Q

The absence of water in a Cr-based oxidation leads to what?

A

the formation of the aldehyde

46
Q

What does hydration lead to for terminal alkynes?

A

ketones

47
Q

What does hydroboration lead to for terminal alkynes?

A

aldehydes

48
Q

Why are aldehydes more electrophilic than ketones?

A

1) lower steric hinderance
2) lower stability of partial positive charge on C

49
Q

Describe the rate of hydration of an aldehyde compared to a ketone?

A

aldehydes are hydrated at a much higher rate

50
Q

Why is HCN not often used in Cyanohydrin formation?

A

HCN is highly toxic

51
Q

How would you push an acid-catalyzed acetal/ketal formation to the right?

A

the presence of a large excess of alcohol reactant

52
Q

Are acetals and ketals reactive towards nucleophiles?

A

no

53
Q

Are amines more or less nucleophilic than alcohols?

A

more (no need for catalyst)

54
Q

Are carboxylic acids more or less electrophilic than aldehydes/ketones?

A

less electrophilic

55
Q

How do you name a carboxylic acid?

A

replace the -e ending with -oic acid

56
Q

True or False: carboxylic acids have priority over other functional groups

A

True

57
Q

Why are carboxylic acids less electrophilic than ketones/aldehydes?

A

the lone par on the hydroxyl oxygen stabalizes the structure through resonance

58
Q

Why is the melting point of carboxylic acids so high?

A

hydrogen-bonding between the hydroxy groups of one acid and the carbonyl oxygen of a second contribute to strong intermolecular attractive forces

59
Q

What is the pKa of carboxylic acids?

A

around 5

60
Q

What is the pKa of alcohols?

A

around 16

61
Q

Why are carboxylic acids more acidic than alcohols?

A
  • the conjugate base of a carboxylic acid is more stable (multiple resonance forms)
  • the inductive effect
62
Q

What substituents are involved in the inductive effect?

A

electronegative substituents such as halogens increase acidity

63
Q

True or False: the inductive effect is distance dependent

A

true

64
Q

Will a closer substituent cause a more or less significant change in pH?

A

more

65
Q

What is the major limitation of the use of a Grignard reaction to make a carboxylic acid?

A

functional group incompatibility with Grignard reagents

66
Q

What is another way to create a carboxylic acid?

A

hydrolysis of nitrile (carbon of nitrile becomes carbonyl carbon)

67
Q

What are two common ways to prepare nitriles?

A

1) nucleophilic substitution of alkyl halides
2) addition of potassium cyanide to aldehydes and ketones

CH223 (5 decks)

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