Organometallic reagents, water and alcohols Flashcards

1
Q

Grignard reagent NA draw mechanism

A

see notes

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2
Q

Why is dry ether added?

A

stabilises organometallic and increases its ability to react

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3
Q

why are strictly anhydrous reaction conditions needed?

A

R-metals destroyed by traces of water

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4
Q

RLi draw reaction with water

A

see notes

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5
Q

What is the aqueous workup?

A

when a source of protons is added in a separate step

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6
Q

Draw out reaction of bromobenzene to primary alcohol (you have to add own reagent)

A

see notes

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7
Q

draw out reaction of chloroethane to carboxylic acid

A

see notes

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8
Q

HCl (aq) and HCl, H2O on arrows….

A

mean same thing

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9
Q

How to organometallics react with water?

A

very rapidly and exothermically to produce hydrocarbon as they are strong bases

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10
Q

CH3MgBr PKa?

A

48 (same as methane)

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11
Q

PhLi PKa?

A

43 (same as benzene)

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12
Q

How would EtMgBr react with an alkyne?

A

see notes

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13
Q

How would BuLi react with an amine?

A

see notes

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14
Q

What is the most acidic of the hydrocarbons and what is PKa?

A

alkyne, 24

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15
Q

Terminal CH of an alkyne…

A

Is easily deprotonated by R-Metal

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16
Q

Draw out reaction scheme for alkyne and BuLi, giving conditions

A

see notes (conditions are -78 degrees, THF)

17
Q

Alkyne and NaNH2 reaction scheme

A

see notes (conditions -33 degrees, THF)

18
Q

LiNH2…

A

is a strong non-nucleophilic base that accepts a proton

19
Q

Alkyne anions…

A

Are very good carbon nucleophiles, react with carbonyls, epoxides, and substitute primary SN2 substrates

20
Q

ketone plus alkyne organolithium plus HCl (aq)…

A

see notes

21
Q

draw out reaction scheme for epoxide with alkyne organolithium

A

see notes

22
Q

draw out reaction scheme for primary bromide with alkyne organolithium

A

see notes

23
Q

What are hydrates

A

2x OH attached to one carbon, form when water reacts with aldehydes/ketones

24
Q

Hemiacetals?

A

1x OR group 1x OH group, formed when alcohol reacts with aldehyde/ketone

25
Q

Acetals?

A

2x OR groups, formed when acetal reacts with alcohol

26
Q

Large R groups effect on acetal formation?

A

Less formed due to steric hindrance reducing carbonyl reactivity

27
Q

Ring strain effect on amount of acetal formed?

A

More formed, release of ring strain with increased acetal bond angle

28
Q

EWGs effect on acetal formation?

A

More formed, reason beyond 1A

29
Q

Give hydrate formation mechanism

A

see notes

30
Q

Give acetal formation mechanism

A

see notes

31
Q

Why must acetal formation be acid mediated?

A

OH needs to be made into good leaving group