Alcohols and Epoxides Flashcards

1
Q

Alcohols

A
  • Polar sp3-hybridised oxygen atom
  • Creates a permanent dipole
  • soluble in water and can form hydrogen bonds
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2
Q

Synthesis of alcohols

A
  • Nucleophilic substitution on an alkyl halide
  • Via Sn2 mechanism compete with elimination
  • Markovnikov product more carbon cations (oxymercuration)
  • Acid catalysed hydration with H+
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3
Q

Acetylide ion reacting with formalderhyde

A

Formation of primary alcohol

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4
Q

Reagent in Markovnikov

A

Boron

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5
Q

Reagent in AntiMarkovnikov

A

Mercuary

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6
Q

Organometallic compound

A
  • Covalent bonds between carbon atoms and metal ions
  • Has nucleophilic carbon atoms strong nucleophile
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7
Q

Grignard Reagents

A
  • Groups are not acidic enough to be deprotonated by NaNH2
  • When ketone or alderhyde is converted to alohol with another group
  • Alkyl halide with magnesium metal in a anhydrous ether solution
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8
Q

Oxidation

A
  • Loose H2 or adding oxidising agent
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9
Q

Reduction

A
  • Loose O, O2 or X2 or adding reducing agent
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10
Q

Oxidation of primary alcohol reagent

A
  • NaOCl or chromic acid H2CrO4
  • Forms alderhyde
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11
Q

Oxidation of primary alcohol to alderhyde

A
  • Dess–Martin periodinane
  • NaOCl
  • Forms carboxylic acid
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12
Q

Oxidation of alcohol in body Ethanol

A
  • Ethanol reacts with the reagent NAD in the liver
  • The alcohol dehydrogenase forms acetalderhyde
  • then acetalderhyde reacts with NAD again and is oxidsed to acetic acid - not toxic
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13
Q

Markovnikov product

A

Acid-catalysed hydration with H2O
Oxymercuration–demercuration
Hg(OAc)2 followed by NaBH4

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14
Q

Chemical agents

A
  • Disinfection on inanimate objects and antiseptic for human tissue
  • Only few chemicalsagen achieve sterility
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15
Q

Factors that influence efficacy

A
  • Kind of organism
  • Degree of contamination
  • Time of exposure
  • Nature of the material treated
  • Concentration of disinfectant
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16
Q

Synthesis of Alcohols from Alkenes

A
  • Dihydroxylation synthesis add potassium manganite and hydroxyl ion
  • Alkene turns to peroxyacid then to epoxide then carboxylic acid to alcohol
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17
Q

Organolithium Reagent

A
  • Lithum reacts with halide to for organolithium reagent
  • Strong nucleophiles and bases
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18
Q

Alcohol synthesis with Grignard reagent

A
  • Formation of grignard where magnesium reacts with an alkyl halide in an anhydrous ether
  • Grignard reagent attacks a carbonyl compound to form alkoxide salt
  • After first reaction is complete water is added to protonate the alkoxide and give alcohol
  • Alcohol with new Carbon-Carbon bond formed
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19
Q

Epoxide with organometallic reagent

A
  • Nucleophilic displacement of epoxide forming a primary alcohol
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20
Q

Organometallic reagent with acid chloride and ester

A
  • Both form tertiary alcohol
  • Formation of unstable intermediate
  • Formation of Ketone then alkoxide finally tertiary alcohol
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21
Q

Reduction of C=O synthesis of primary and secondary alcohol

A
  • Hydride reagent add hydride ion reducing C=O to alkoxide ion
  • Sodium Borohydride transfers a hydride ion to form carbon forming alkoxide
  • Alcohol solvent protonates the alkoxide
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22
Q

Reduction of C=O using LiAlH4

A
  • LAH transfers hydride ions to hydride ions forming an alkoxide ion
  • After first reaction is complete water or diluted acid is added to protonate alkoxide
  • Stronger than NaBH4 easily reducing ketones and alderhydes
  • Reduces carbonyl groups and esters
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23
Q

Neither oxidation or reduction

A
  • Add or loss of H+, -OH, and H2O
24
Q

Oxidation and reduction can be identified by

A
  • Counting the number of carbon oxygen bonds usually converting C-H to C-O
25
Q

Alcohol reacting as weak nucleophile

A
  • Forms into a strong nucleophile by loosing the hydrogen (Alkoxide ion)
  • Alkoxide ion attack weak electrophile such as the alkyl halide
  • Another way is weak nucleophile attacking a strong electrophile
26
Q

Alcohol acting as an electrophile

A
  • Poor electrophile turns to a good electrophile by loosing the hydrogen to produce water
  • OH is a poor leavibng group needs to be converted to good leaving group
  • OH bond broken off the hydrocarbon when reacting as electrophile
27
Q

Formation of Tosylates

A
  • Convert OH to a better tosylate leaving group
  • Alkyl tosylate made from tosyl chloride
  • P- toluenesulfonyl chrolide addition of pryridine base forming tosylate ester the bond is then broken
  • Sn2 displacement of tosylate ion
  • Formed in to diffrent functional group via Sn2 mechanism
28
Q

Tosylate ester + Hydroxide ion

A
  • Alcohol + tosylate ion
  • (Must be unhindered primary or secondary alkyl group )
29
Q

Tosylate ester + Cyanide ion

A
  • Nitrile + Tosylate ion
  • (Must be unhindered primary or secondary alkyl group )
30
Q

Tosylate ester + Halide ion

A
  • Alkyl halide + Tosylate ion
  • (Must be unhindered primary or secondary alkyl group )
31
Q

Tosylate ester + Alkoxide ion

A
  • Ether + tosylate ion
  • (Must be unhindered primary or secondary alkyl group )
32
Q

Tosylate ester + Ammonia ion

A
  • Tosylate ion +amine salt
  • (Must be unhindered primary or secondary alkyl group )
33
Q

Tosylate ester + LAH

A
  • Alkane + Tosylate ion
  • (Must be unhindered primary or secondary alkyl group )
34
Q

Conversion of alcohol to alkyl halide (Hydrophilic acids HBr, HCl and HI

A
  • Conversion of poor leaving hydroyl group to good leaving water group
  • Protonation substitution Sn1 for 3 and 2 alcohol and for primary Sn1
35
Q

Reaction with phosphorus halide

A
  • Reaction with primary and secondary alcohol but not with tertiary
36
Q

Dehydration reaction of alcohol

A
  • Protonation of hydroxy group due to being poor leaving group
  • Strong acid added forming water which is good leaving group and H2SO4
  • Ionisation to a carbon cation slow step
  • Deprotonation to give alkene fast step
  • E1 elimination with tertiary and secondary not primary
37
Q

Bimolecular condensation

A
  • Nucleophile alcohol attacks electrophile via Sn2 displacement (primary alcohol) formation of an ether
38
Q

Condensation

A
  • Joins 2 or more molecules often with loss of a small molecule such as water under acidic dehydration conditions 2 reactions compete
39
Q

Elimination

A
  • Dehydration to give an alkene
40
Q

Substitution

A
  • Condensation to give an ether
41
Q

Esterification of alcohol
(Fischer esterification)

A
  • Alcohol + carboxylic acid = ester + water
42
Q

Powerful way of forming an ester

A
  • Alcohol + acid chloride = Ester (addition of pryodine to neutralise)
43
Q

Inorgainc esters

A
  • Alkoxy group replaces a OH of inorganic
44
Q

Para-toluenesulfonyl chloride esterification

A
  • Addition with alcohol and prydine forms tosylate ester and HCl
45
Q

Formation of sulfate diester

A
  • Sulphuric acid + alcohol = Sulphate ester
  • Sulphate ester + alcohol = Sulphate diester
46
Q

Formation of nitrate ester

A
  • Nitric acid + alcohol = Nitrate ester and alcohol
47
Q

Phosphoric acid esterification

A
  • Can form triester phosphate 3 levels of esterification
48
Q

Williamson ether synthesis

A
  • Alkoxide ion is a strong nucleophilic base can react with primary alkyl halide and tosylate to form ether
  • Leaving group can be a tosulate or a primary halide to form ether
  • If alkyl halide is tosylate it is hindered by elimination
49
Q

Ether formation

A
  • From alkyl or aryl groups may be symetrical ether or unsymetrical
  • Relatively unreactive and commonly used as a solvent
50
Q

Epoxide

A
  • 3 membered cyclic ether
  • Used to add OH group to any compound as it is highly reactive
51
Q

Synthesis of epoxide

A
  • Alkene + Peroxyacid = epoxide + acid
  • Base promoted cyclisation halohydrins
  • Halohydrin + hydroxyl forms intermediate then epoxide which is an internal Sn2 reaction
52
Q

Opening of epoxide via water

A
  • Acid-Catalysed in water to form glycols
  • Protonation of oxygen followed by Sn2 attack by water
53
Q

Opening of epoxide via alcohol

A
  • Protonation of oxygen forming good leaving group followed by alcohol attack Sn1 as alkocyl group bonds to more highly substitued carbon
54
Q

Opening epoxide via hydrohalic acid

A
  • Using a hydrogen halide forming a hydroylhalide then adding another hydrogen halide
55
Q

Opening of epoxide with base catalyst

A
  • Addition of either alcohol or hydroxide ion
  • Attacking of the less hindered carbon atom in an Sn2 displacement
56
Q

Opening of epoxides with organometallics

A
  • R-MgX attacks epoxide by attacking least hindered carbon atom and R is bonded to the less substituted carbon
  • Nucleophilic displacement of epoxide