Organic Reactions Flashcards
(136 cards)
1
Q
What does an acid-base reaction form?
A
Conjugate acid and conjugate base
2
Q
What is required of the reactants for an acid-base reaction to run?
A
Reactants are stronger than the products
3
Q
What is the definition of a lewis acid?
A
Electron acceptor, electrophile
4
Q
Is a lewis acid an electrophile or nucleophile?
A
Electrophile
5
Q
Is a lewis base an electrophile or nucleophile?
A
Nucleophile
6
Q
What is the definition of a lewis base?
A
Electron donor, nucleophile
7
Q
Is an electron donor a lewis acid or base?
A
Base
8
Q
Is an electron acceptor a lewis acid or base?
A
Acid
9
Q
What is a coordinate covalent bond?
A
Bond in which both bonding e- come from the same atom
10
Q
What is the definition of a Bronsted-Lowry acid?
A
H+ donor
11
Q
What is the definition of a Bronsted-Lowry base?
A
H+ acceptor
12
Q
Is a proton acceptor a Bronsted-Lowry acid or base?
A
Base
13
Q
Is a proton donor a Bronsted-Lowry acid or base?
A
Acid
14
Q
What is the definition of an amphoteric molecule?
A
Can act as a Bronsted-Lowry acid or base depending on the solution
15
Q
Is water an acid or base in a basic solution and what product is formed?
A
Acid, donates H+ to make OH-
16
Q
Is water an acid or base in an acidic solution and what product is formed?
A
Base, accepts H+ to make H3O+
17
Q
What are some examples of amphoteric molecules?
A
H2O
AL(OH)3
HCO3-
HSO4-
18
Q
What is Ka and how is it calculated?
A
Acid Dissociation Constant, represents the strength of an acid
Ka=([H+][A-])/[HA]
19
Q
pKa
A
-log(Ka)
20
Q
Does a smaller Ka indicate a stronger or weaker acid?
A
Stronger
21
Q
What pKa defines a strong acid?
A
Lower,
22
Q
What does it mean if an acid is strong?
A
Dissociates in aqueous solution
23
Q
Does acidity increase or decrease as you go down the periodic table?
A
Increase
24
Q
Does acidity increase or decrease as you go up the periodic table?
A
Decrease
25
Does acidity increase or decrease with electronegativity?
Increase
26
Which hydrogen is easily lost in a carbonyl compound?
Alpha hydrogen (bonded to the alpha carbon, which is next to the carbonyl group)
27
Is electro and nucleophilicity a thermodynamic or kinetic property?
Kinetic property based on reaction rates
28
What is a kinetic property based on?
Reaction rates
29
What is a thermodynamic property based on?
Reaction equilibrium
30
Is acid-base strength a thermodynamic or kinetic property?
Thermodynamic based on acid-base equilibrium
31
What are nucleophiles?
"nucleus loving" with lone pairs or pi bonds that can form new bonds
32
Is nucleophilicity similar to acidity or basicity?
Basicity
33
Are nucelophiles usually positive or negative?
Negative
34
Do electronegative atoms increase or decrease nucleophilicity?
Decrease because they are electron withdrawing (reduce negative charge)
35
Do bulky groups increase or decrease nucleophilicity?
Decrease because they provide steric hindrance
36
```
Rank the following in decreasing reactivity:
Ester
Amide
Anhydride
Carboxylic Acid
```
Anhydride>Carboxylic Acid/ Ester > Amide
37
Do protic solvents increase or decrease nucleophilicity?
Decrease by protonating the nucleophile
38
What are electrophiles?
"Electron-loving" species with a positive charge or positively polarized atom that acts as an electron acceptor
39
Do electrophiles behave like acids or bases?
Acids
40
Heterolytic Reactions
When a bond is broken and both electrons go to the same atom
41
Are weak bases good or bad leaving groups?
Good
42
Why are weak bases good leaving groups?
They are stable with extra electrons
43
How many steps is an Sn1 reaction?
Two
44
What are the step(s) of an Sn1 reaction?
1. Leaving group leaves and generates a carbocation
| 2. Nucleophile attacks the carbocation
45
What is the stereochemistry of the products of an Sn1 reaction?
Usually racemic
46
What reaction order is an Sn1 reaction?
First order
47
Which step is rate-limiting in an Sn1 reaction?
First step
48
What type of compounds are best suited for Sn1 reactions?
Bulky, more substituted alkanes
49
How many steps is an Sn2 reaction?
One
50
What are the step(s) of an Sn2 reaction?
1. Back-side attack by nucleophile at the same time the leaving group leaves
51
What is the stereochemistry of the products of an Sn2 reaction?
Inverted compared to the original
52
What reaction order is an Sn2 reaction?
Second order
53
What type of compounds are best suited for an Sn2 reaction?
Strong nucleophiles and alkanes without steric hindrance
54
What happens in redox reactions?
The oxidation states of the reactants change
55
What type of compounds are best suited for an Sn2 reaction?
Strong nucleophiles and alkanes without steric hindrance
56
What is the most oxidized form of carbon and what is the oxidation state?
CO2, +4
57
What is the most reduced form of carbon and what is the oxidation state?
CH4, -4
58
Is oxidation loss or gain of electrons?
Loss
59
Is reduction loss or gain of electrons?
Gain
60
Does an oxidizing agent accept or donate electrons?
Accepts
61
Is an oxidizing agent oxidized or reduced?
Reduced
62
Does a reducing agent accept or donate electrons?
Donate
63
Is a reducing agent oxidized or reduced?
Oxidized
64
Does reactivity increase or decrease with oxidation?
Increase
65
How are carbonyl compounds protected in reaction?
Addition of two equivalents diol (or geminal diol) to form acetal or ketal
66
What is an acetal?
Carbon bound to two OR groups from alcohol (with other two bonds to R groups and H)
67
What is a ketal?
Carbon bound to two OR groups from alcohol (with other two bonds to R groups)
68
What is the difference between acetal and ketal?
One bond to H in acetal, all bound to R groups in ketal
69
How are protecting groups removed?
Acid and heat
70
How are alcohols protected in reaction?
Reduced to t-butyl ethers
71
How is alcohol oxidized to an aldehyde?
PCC
72
Is alcohol to aldehyde oxidation or reduction?
Oxidation
73
What is phenol?
-OH attached to aromatic ring
74
Is phenol more or less acidic than C-chain alcohols and why?
More because of resonance stabilization through the ring
75
What is ortho designation?
Two groups on adjacent carbons in ring
76
What is meta designation?
Two groups separated by one C in a ring
77
What is para designation?
Two groups on the opposite sides of a ring
78
Do alcohols have higher or lower boiling points than their alkane counterparts and why?
Higher due to inter molecular hydrogen bonding
79
Rank the following by increasing BP:
Aldehyde
Alkane
Alcohol
Ketone
Alkane
Aldehyde/Ketone
Alcohol
80
What happens when a primary alcohol is reacted with PCC?
Aldehyde
81
What happens when a primary alcohol is reacted with a strong oxidizing agent?
Carboxylic Acid
82
What happens when a secondary alcohol is reacted with PCC?
Ketone
83
What happens when a secondary alcohol is reacted with a strong oxidizing agent?
Ketone
84
What is sodium dichromate?
Na2Cr2O7
85
What is potassium dichromate?
K2Cr2O7
86
Is Na2Cr2O7 an oxidizing or reducing agent?
Oxidizing
87
Is LiAlH4 an oxidizing or reducing agent?
Reducing
88
What is mesylate?
S double bound to two O, single bound to one O with a negative charge, and single bound to methyl group
SO3CH3-
89
What is tosylate?
S double bound to two O, single bound to one O with a negative charge, and single bound to benzene with a methyl group in para position
90
What is the purpose of reacting mesylates and tosylates with alcohols?
1. Makes them into better leaving groups
| 2. Can serve as protecting groups as they will not react with oxidizing agents
91
Do mesylates react with oxidizing agents?
No
92
Do tosylates react with oxidizing agents?
No
93
What is a quinone?
6 carbon ring with two double bonds opposite one another and two =O in para position
94
How are quinones formed?
Oxidation of phenol
95
What is formed when phenol is oxidized?
Quinone
96
What are two examples of biological quinones?
Vitamin K1 and K2
97
What is formed when quinone is oxidized?
Hydroxyquinone
98
What is hydroxyquinone?
Quinone with hydroxyl group
99
What is butyraldehyde?
Butanal
100
What is valeraldehyde?
Pentanal
101
What is an aldehyde attached to a ring called?
Carbaldehyde
102
What is carbaldehyde?
An aldehyde attached to a ring
103
Do carbonyls act as electophiles or nucleophiles?
Both
104
When do carbonyls act as electrophiles?
Nucleophile attacks the carbon which is partially positive due to electron-withdrawing properties of Oxygen
105
Are aldehydes or ketones more electrophilic and why?
Aldehydes because they lack steric hindrance and do not have electron-donating alkyl groups
106
Are alkyl groups electron donating or withdrawing
Donating
107
Do electron donating groups increase or decrease electrophilicity?
Decrease
108
Do electron withdrawing groups increase or decrease electrophilicity?
Increase
109
What does a ketone plus nucleophile form?
Secondary alcohol
110
What is a hydration reaction?
Formation of geminal diols from ketone/aldehydes with water
111
What happens when water is added to aldehyde?
Geminal diol
112
What is a hemiacetal and how is it formed?
Addition of one equivalent of alcohol to acetal
C boudn to R, OH, OR, and H
113
What happens when ammonia is added to carbonyl?
Formation of imine through loss of water
114
What is the strucute of an imine?
C bound to two R groups and double bound to N-H
115
Hydrazine
H2N-NH2
116
Semicarbide
H2N-NH-carbonyl-NH2
117
Hydrogen cyanide
HCN
118
What is cyanohydrin?
C single bound to two R groups, OH, and -CN
119
How is cyanohydrin formed?
HCN plus ketone/aldehyde
120
How are ketones and aldehydes transformed to alcohols?
Reduction by hydride reagents
121
What are examples of hydride reagents?
LiAlH4
| NaBH4
122
What is an alpha hydrogen?
Hydrogen attached to alpha carbon (carbon attached to carbonyl carbon)
123
When do carbonyls act as nucelophiles?
When ketone/aldehyde is reacted with base, alpha carbon is lost and carbanion is formed
124
What is keto-enol tautomerization?
Move H and double bond in ketone - C=C and H transferred to O to make OH
125
Is keto or enol form favored in tautomerization?
Keto
126
Enamination
Tautomerization between imine and enamine
Move H and double bond in imine - C=C bound to NH2
127
Is imine or enamine form favored in tautomerization?
Imine
128
What are the steps of the Michael addition?
1. Base deprotonates the alpha carbon of ketone/aldehyde forming a carbanion
2. Carbanion attacks a double bond of an alpha-beta unsaturated carbonyl
129
What is a kinetic enolate?
Double bond moves to the less substituted alpha carbon
130
Under what reaction conditions is a kinetic enolate formed?
Fast
Irreversible
Strong, bulky base
Lower temperature
131
Under what reaction conditions is a thermodynamic enolate formed?
Slow
Reversible
Higher temperature
Weak, small base
132
What is a thermodynamic enolate?
Double bond moves to the more substituted alpha carbon
133
Is a kinetic or thermodynamic enolate more stable?
Thermodynamic
134
What happens to an aldehyde or ketone in the presence of a base?
Aldol condensation
135
What is an aldol condensation?
Aldehyde or ketone acts as both a nucleo and electrophile to form a C-C bond in the presence of a base
136
What is an aldol?
Molecule that contains an alcohol and an aldehyde
