Prelim Exam 2: Sulfur Compounds; Aldehydes and Ketones; Carboxylic Acids, Carboxylates, and Nitriles; Multistep Synthesis; Polymers and Cyclic Compounds (Chem 322- Organic Chemistry) Flashcards
1
Q
thiols
A
R-SH
2
Q
mercapto group
A
-SH group
3
Q
thiol nomenclature
A
name parent alkane and add “thiol” to the end of the name
4
Q
sulfide nomenclature
A
named as “sulfide” compounds: alkyl sulfide or alkyl-thio alkane
5
Q
sulfide
A
R-S-R
6
Q
thiol preparation
A
from alkyl halides through Sn2 displacement with sulfur nucleophile such as SH- anion (works poorly unless excess SH is present due to competing Sn2 reaction with alkyl halide to give sulfide as by-product); using thiourea works better
7
Q
thiol reaction
A
2 R-SH oxidized by Br2 or I2 to yield disulfides (R-S-S-R)
8
Q
sulfide preparation
A
treatment of thiol with base gives thiolate ion (RS-) which undergoes reaction with primary or secondary alkyl halide [R-SH –1) NaH 2) R-X –> R-S-R]
9
Q
sulfur compounds are more nucleophilic than ethers
A
because electrons are farther from the nucleus and less tightly held than those on oxygen
10
Q
sulfide reactions
A
dialkyl sulfides react rapidly with primary halides by Sn2 to give sulfonium ions (R3S+) – which are useful alkylating agents because a nucleophile can attack one of groups bonded to positively charged sulfur to displace a neutral sulfide as leaving group……. oxidation of sulfide with H2O2 to yield sulfoxide (R2SO) with further oxidation of sulfoxide with peroxyacid yielding a sulfone (R2SO2) [ R-S-R –H2O2–> RSOR –CH3CO2H–> RSOOR]
11
Q
DMSO (dimethyl sulfoxide)
A
common polar aprotic solvent
12
Q
spectroscopy of ethers
A
infrared spectroscopy– absorption due to C-O single bond at 1050-1150 cm^-1… NMR spectroscopy– H NMR absorptions in 3.4-4.5 delta region for H on carbon next to O in ether and epoxide hydrogens absorb at 2.5-3.5 delta region
13
Q
1) NaH 2) RCH2X
A
williamson ether synthesis from primary alcohols to form ethers
14
Q
1) ROH, (CF3CO2)2Hg / 2) NaBH4
A
alkoxymercuration/demercuration from alkene to form ethers
15
Q
HX, H2O
A
cleavage of ethers by HBr or HI to form an alkyl halide and alcohol
16
Q
H3O or HBr
A
acid-catalyzed epoxide opening to yield a diol or an alkyl halide alcohol
17
Q
RO-, ROH or 1) ether / 2) H3O+
A
base-catalyzed epoxide opening to yield a alkyl ether alcohol or a primary alcohol
18
Q
1) (H2N)2C=S / 2) H2O, NaOH
A
reaction of alkyl halide to yield thiol
19
Q
I2, H2O
A
oxidation of 2 RSH to yield disulfide (R-S-S-R)
20
Q
RS- + alkyl halide
A
yields sulfide (R-S-alkyl)
21
Q
H2O2
A
oxidation of sulfides to sulfoxides
22
Q
RCO3H
A
oxidation of sulfides to sulfones
23
Q
sulfoxide
A
R2S=O
24
Q
sulfone
A
R-SO2-R
25
sulfonic acid
SO3H
26
sulfuric acid
H2SO4
27
dialkyl sulfate
R2SO4
28
nucleophile
nucleus loving; attracted to positive charge... has a negative charge, a partial negative charge, or a pi bond... provides pair of electrons to form bond
29
electrophile
electron loving; attracted to negative charge... has positive charge, a partial positive charge, or a leaving group... accepts pair of electrons to form bond
30
deprotonates phenols
NaOH or NaH
31
deprotonates alcohols
NaH
32
aldehyde nomenclature
replace "e" of parent name with "al"; no number necessary because aldehydes are always carbon 1 and must always be in parent chain; cyclic aldehydes are named with suffix "carbaldehyde" on end of parent name
33
nomenclature ending priority
carboxylic acid > nitrile > aldehyde > ketone > alcohol > alkyne > alkene > halogens, alkyl, alkoxy
34
ketone nomenclature
replace "e" ending with "one"; no number if ketone can only be in one position in a parent chain; numbering of parent chain begins at end closest to carbonyl carbon; locant must be used with ketone name
35
acyl group
RC=O
36
formyl group
HC=O
37
acetyl group
CH3-C=O
38
benzoyl group
benzene-C=O
39
benzyl group
-CH2-benzene
40
1) RCOCl / 2) AlCl3
friedel-crafts acylation to convert a benzene into a phenyl ketone
41
HgSO4, H2SO4, H2O
conversion of alkynes into ketones
42
DMP, PCC or KMnO4 or CrO3
oxidation of secondary alcohols to ketone
43
1) O3 / 2) Zn, H+
ozonolysis of alkenes to yield a ketone or aldehyde
44
R2CuLi, -:R
reaction of cuprates with acid chlorides to yield ketones
45
DMP or PCC
oxidation of primary alcohols to yield aldehydes
46
1) BH3 / 2) H2O2, -OH
hydration of terminal alkynes to yield an aldehyde
47
1) DIBAH / 2) H3O+
partial reduction of esters to yield an aldehyde and an alcohol
48
carbonyl group
C=O
49
carbonyl characteristics
carbonyl carbon sp^2 hybridized and forms 3 sigma bonds and 1 pi bond... planar about double bond and have 120 degree bond angles... carbon-oxygen bond is strongly polarized because of high electronegativity of oxygen relative to carbon (carbonyl carbon acts as electrophile and carbonyl oxygen acts as nucleophile)... electron withdrawing group
50
oxo
name of ketone functional group substituent when other priority groups are in the compound
51
aldehydes are generally more reactive than ketones in nucleophilic addition reactions
because there is less steric crowding from large substituents and because a primary carbocation is higher in energy and thus more reactive
52
aldehydes/ketones + carbon nucleophile
yields alcohol
53
aldehydes/ketones + nitrogen nucleophile
yields imine
54
aldehydes/ketones + oxygen nucleophile
yields acetal
55
Wolff-Kishner Reaction
treatment of aldehyde/ketone with hydrazine (H2NNH2) in presence of KOH to yield an alkane (through intermediate hydrazone intermediate (R2C=NNH2)
56
acetal
R2C(OR)2; formed upon reaction of aldehydes/ketones with 2 equivalents of alcohol; act as protecting groups for aldehydes/ketones and can be removed with H3O+
57
hemiacetal
R2C(OH)OR; formed upon reaction of aldehydes/ketones with 1 equivalent of alcohol
58
carboxylic acid
RCOOH
59
ester
RCOOR
60
acid chloride
RCOCl
61
ketone
RCOR
62
anhydride
RCOOCOR
63
aldehyde
RCOH
64
amide
RCONR2
65
epoxide ring opening occurs by Sn2
attacks least substituted carbon if no tertiary carbon is present or ALWAYS when the nucleophile is negative or a nitrogen
66
epoxide ring opening occurs by Sn1
attacks most substituted carbon only if tertiary carbon is present (and no negative nucleophiles)
67
aldehyde/ketone + carbon nucleophile
yields an alcohol through 1) addition then 2) protonation
68
aldehyde/ketone + nitrogen nucleophile (primary amine)
yields an imine
69
aldehyde/ketone + nitrogen nucleophile (primary amine) STEPS
1. addition (of NH2-R)... 2. proton transfer (H from N to O)... 3. protonation (of hydroxyl group)... 4. elimination (of water)... 5. deprotonation (remove H from N using water to form C=N bond)
70
REVERSE REACTION: imine to aldehyde/ketone STEPS
1. protonation (of N of C=N)... 2. addition (of water)... 3. deprotonation (remove H from water group using water)... 4. protonation (add H to N using H3O+)... 5. elimination (remove NH2-R group)... 6. deprotonation (remove H from O using water to form C=O bond)
71
aldehyde/ketone + oxygen nucleophile (alcohol) STEPS
1. protonation (H from H3O+ adds to O)... 2. addition (of ROH to electrophilic C)... 3. deprotonation (removed H from OR group to yield hemiacetal)... 4. protonation (add H to OH group from H3O+)... 5. substitution (Sn1) (water group leaves followed by addition of ROH)... 6. deprotonation (H from ROH is removed to form acetal)
72
aldehyde/ketone + oxygen nucleophile (alcohol)
yields acetal
73
REVERSE REACTION: acetal to aldehyde/ketone STEPS
1. protonation (add H to OR group using H3O+)... 2. substitution (kick off ROH group followed by addition of water group)... 3. deprotonation (remove H from water group using water)... 4. protonation (of OR group with H from H3O+)... 5. elimination (remove ROH group)... 6. deprotonation (remove H from O to form C=O bond)
74
wittig reaction
conversion of aldehydes/ketones to alkenes using a ylide (R2C=PPh3); prepares mono/di/tri substituted alkenes (not a tetra substituted alkene); yields a pure alkene of predictable structure: the C=C bond always forms where C=O group was
75
cannizzaro reaction
nucleophilic addition of -OH to an aldehyde to give a tetrahedral intermediate, which expels a hydride ion as a leaving group is oxidized, while a second aldehyde accepts the hydride ion in another nucleophilic addition step and is reduced
76
conjugated (1,4) addition to α, β unsaturated aldehydes/ketones
nucleophile adds to beta carbon and a hydrogen adds to alpha carbon (adding to the alkene portion to form an alkane portion) while ketone/aldehyde is retained
77
conjugate addition of amines
primary and secondary amines add to α, β unsaturated aldehydes/ketones to yield β-amino aldehydes/ketones; proceed with thermodynamic control to form more stable addition product
78
conjugate addition of water
H2O can add to α, β unsaturated aldehydes/ketones to yield β-hydroxyl aldehydes/ketones, but unsaturated aldehydes/ketones predominate at equilibrium
79
conjugate addition of alkyl groups: organocopper reactions
alkyl group adds to α, β unsaturated ketones (NOT aldehydes) in a 1,4 addition reaction; uses lithium diorganocopper reagent (R2CuLi) to ensure conjugate addition (grignard reagents would add to ketone)
80
addition of primary amine to ketone/aldehyde
yields imine
81
addition of secondary amine to ketone/aldehyde
yields enamine
82
stronger base
more electropositive atom with negative charge
83
better nucleophile
larger atom and more electropositive
84
forming wittig reaction reagent
MUST start with a PRIMARY alkyl halide + Ph3P (as it is an Sn2 reaction)... add butyl lithium to form RC=P+Ph3
85
wittig reaction steps
1. Ph3P... 2. butyl lithium (CH3CH2CH2CH2Li)... 3. ketone or aldehyde
86
infrared spectroscopy of aldehydes/ketones
strong C=O absorption at 1660-1770 cm^-1; aldehydes have additional C-H absorptions at 2700-2760 cm^-1 and 2800-2860 cm^-1 (which is the distinguishing characteristic between aldehydes and ketones)
87
nuclear magnetic resonance spectroscopy
aldehyde protons absorb at 10 delta (distinctive because no other absorptions occur in this region); hydrogens on the carbon next to a carbonyl group normally absorb at 2-2.3 delta... carbonyl group carbon atoms have distinctive 13C NMR resonances from 190-215 delta (no other kinds of carbons absorb in this region)
88
mass spectrometry
fragment ions from Mclafferty rearrangement and alpha cleavage are visible in mass spectrum
89
1) NaBH4 / 2) H3O+
addition of hydride to aldehydes/ketones to give alcohols
90
1) RMgX / 2) H3O+
addition of grignard reagent to aldehydes/ketones to yield alcohols
91
1) HCN
addition of HCN to aldehydes/ketones to yield cyanohydrins (CN and OH groups)
92
RNH2, H3O+
addition of primary amines to aldehydes/ketones to give imines
93
HNR2, H3O+
addition of secondary amines to aldehydes/ketones to give enamines
94
NH2NH2, KOH
wolff-kishner reaction to aldehydes/ketones to give alkanes
95
2 ROH, H3O+
addition of alcohols to aldehydes/ketones to yield acetals (or hemiacetals with addition of one mol of alcohol)
96
1) Ph3P... 2) BuLi... 3) aldehyde/ketone
wittig reaction: converts primary alkyl halide to yield an alkene
97
RNH2 to α, β unsaturated aldehydes/ketones
yields a β-amino aldehydes/ketones
98
H2O to α, β unsaturated aldehydes/ketones
yields a β-hydroxyl aldehydes/ketones
99
1) R2CuLi / 2) H3O+ to α, β unsaturated aldehydes/ketones
yields a 1,4 addition product to form a longer alkane chain and a ketone
100
carboxylic acid nomenclature
replace terminal "e" of parent name with "oic acid" (CO2H carbon is Carbon 1)... CO2H bonded to a ring causes the compound to have the suffix "carboxylic acid" at end of parent name; conjugate base name has "oate" ending
101
carboxyl group
CO2H as a substituent
102
acyl groups
COR; derived from parent carboxylic acids and are named with "yl" endings or "oyl" endings
103
nitrile
RCN (C is triple bonded to N)
104
nitrile nomenclature
"nitrile" suffix at end of parent name (nitrile carbon is carbon 1).... or can be named as carboxylic acid derivatives: "onitrile" suffix for open chain parent or "carbonitrile" suffix for ring parent (nitrile carbon is attached to carbon 1 but not numbered)
105
properties of carboxylic acids
carboxyl carbon is sp^2 hybridized... carboxylic groups are planar with C-C=O and O=C-O bond angles of approximately 120 degrees... are strongly associated due to hydrogen bonding... higher boiling points than corresponding alcohols... are acidic and react with bases to give metal carboxylate salts (RCO2- Metal+), with the salts being very water soluble and allows purification of acid (acid-base extractions)... more acidic than alcohols due to delocalization of negative charge over two equivalent oxygen atoms (ie-- stabilized by resonance)
106
henderson-hasselbalch equation
pH = pKa + log [A-]/[HA]
107
substituent effects on acidity
more stabilization of carboxylate anion relative to undissociated carboxylic acid will drive equilibrium toward increased dissociation and increased acidity, with more electron-withdrawing atoms helping to delocalize negative charge... halogens closer to carboxylic acid increase acidity due to inductive effects operating through sigma bonds.... benzoic acids with deactivating groups are more acidic
108
carboxylate ion nomenclature
metal alkanOATE
109
oxidation of substituted alkyl benzene with KMnO4 or Na2Cr2O7
yields carboxylic acid
110
oxidation of a primary alcohol or aldehyde with CrO3
yields carboxylic acid
111
hydrolysis of nitriles using 1) NaOH, H2O / 2) H3O+
yields carboxylic acid
112
converting an alkyl halide to a nitrile
use NaCN
113
carboxylation of grignard reagents using CO2, H3O+
yields carboxylic acid
114
for 1,2 addition
use grignard reagents (RMgX) or alkyl lithium (RLi)
115
for 1,4 addition
organo cuprate (R2CuLi), RNH2, R2NH
116
enamine formation (secondary amine + aldehyde/ketone)
1. addition
2. proton transfer
3. protonation
4. elimination
5. deprotonation
117
wolff-kishner reaction (NH2NH2, OH)
Carbonyl converted to a hydrazone (NNH2) then N2 removed with base to yield an alkane... once the base is added to N=N compound, the rest of the reaction is irreversible
118
wittig reaction from primary alkyl halide
1. Ph3P... 2. butyl lithium... 3. ketone/aldehyde... formation of an alkene, with the double bond being where the C=O bond was prior
119
1,2 / 1,4 addition to alpha,beta-unsaturated carbonyls
1. Nucleophile (1,2: RMgX, RLi... 1,4: R2CuLi, RNH2, R2NH)... 2. H3O+ (unless using RNH2 or R2NH, then no H3O+ is needed)
120
formic acid
aka methanoic acid; has one carbon; is a chemical weapon used by ants
121
acetic acid
aka ethanoic acid; has two carbons; is found in vinegar
122
propionic acid
aka propanoic acid; has two carbons; is rancid and pungent
123
buteric acid
aka butanoic acid; has four carbons; is found in rancid butter
124
valeric acid
aka pentanoic acid; has five carbons; is found in valerion root (a sedative)
125
caproic acid
aka hexanoic acid; has six carbons; is the essence of goat
125
caproic acid
aka hexanoic acid; has six carbons; is the essence of goat
126
oxalic acid
dicarboxylic acid with two carbons
127
malonic
dicarboxylic acid with three carbons
128
succinic acid
dicarboxylic acid with four carbons
129
glutaric acid
dicarboxylic acid with five carbons
130
adipic acid
dicarboxylic acid with six carbons
131
pimelic acid
dicarboxylic acid with seven carbons
132
acidity of carboxylic acids increases with
closer electron withdrawing groups (strong deactivators) due to higher inductive effect; having greater delocalization through resonance
133
1) CO2 / 2) H3O+
grignard reagent to carboxylic acid
134
1) NaCN / 2) excess H3O+
converting an alkyl halide into a carboxylic acid
135
1) SOCl2, benzene to an amide
converts the amide to a nitrile
136
1) LiAlH4 / 2) H2O
conversion of nitriles into amines
137
nitrile + grignard reagent
converts nitrile into a ketone
138
spectroscopy of carboxylic acids
IR: OH bond of carboxyl group has broad absorption at 2500-3300 cm^-1 and C=O bond has absorption 1710-1760 cm^-1... NMR: acidic CO2H protons absorbs around 12 delta
139
IR spectroscopy of nitriles
C-N bond absorption between 2230-2250 cm^-1
140
acids with ortho substituents
generally the more acidic form of the acid
141
carboxylic acid + excess NaOH, NaHCO3, NH3, or NH2R
forms conjugate base of the acid
142
epoxide + grignard is classified as
SUBSTITUTION because only a sigma bond is formed and broken
143
deprotonates carboxylic acids
NaOH or NH3 or RNH2 or NaHCO3
144
naming carboxylic acids
find the longest carbon chain including the acid group and begin numbering from the acid carbon... drop the "e" from alkane and add "oic acid"... label substituents as normal and complete the name
145
naming nitriles
circle and name the longest carbon chain containing the nitrile carbon... number from the nitrile carbon and name as alkanenitrile
