Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
132 Cards in this Set
- Front
- Back
|
cyclohexene + bromine gas
|
trans-1,2-dibromocyclohexane (a chiral molecule), via an anti addition and halonium intermediate
|
|
|
does a catalytic hydrogenation of an alkene result in a chiral molecule?
|
yes, but a racemic mixture b/c it can attack from either side
|
|
|
tertiary alkyl halide + water, heat
|
mixture of E1/Sn1 products (an alcohol and an alkene)
|
|
|
tertiary alkyl halide + weak, bulky base
|
E1 - only proceeds by Zaitsev mechanism
|
|
|
bulky base favors Zaitsev or Hoffman?
|
Hoffman
|
|
|
alcohol + acid, heat
|
dehydration, elimination yielding an alkene
|
|
|
Zaitsev elimination
|
results in the most substituted alkene (favored by very strong base)
|
|
|
IR spectroscopy, carbonyl
|
around frequency = 1750 cm-1
|
|
|
IR spectroscopy, alcohol or acid
|
around f = 3000 cm-1, broad
|
|
|
IR spectroscopy, amine (single nitrogen-hydrogen bond)
|
around f = 3000 cm-1, sharp
|
|
|
a deshielded atom in NMR, shifts...
|
downfield (to the left); a nucleus with less electron density surrounding it is easier to exite
|
|
|
splitting peaks
|
a peak will be split into n+1 peaks, where n is the number of chemically non-identical protons within 3 bonds
|
|
|
UV-vis spectroscopy
|
used to examine conjugated systems (this includes peptides, cholesterol)
|
|
|
base peak (of mass spec)
|
the tallest peak corresponds to the most abundant ion, and is assigned a relative abundance of 100
|
|
|
molecular ion peak
|
or parent ion peak, M+ = the peak furthest to the right, i.e. with the highest mass to charge ratio; this usually represents the original molecular cation; its molecular wt is usually equal to the molecular wt of the parent molecule
|
|
|
m-cresol
|
m-methylphenol
|
|
|
alcohol boiling point?
|
much higher than those of the analogous hydrocarbonds due to H-bonding
|
|
|
acidity of an alcohol vs. phenol hydrogen?
|
hydroxyl hydrogens of phenols are more acidic than those of alcohols due to resonance structures that distribute the negative charge throughout the ring
|
|
|
alkyl groups on alcohols and acidity
|
acidity decreases as more alkyl groups are attached b/c the e- donating groups destabilize the alkoxide anion. e- withdrawing groups stabilize the alkoxy anion, making the alcohol more acidic
|
|
|
wood alcohol
|
methanol
|
|
|
grain alcohol
|
ethanol
|
|
|
reduction of aldehydes, ketones, carboxylic acids, or esters
|
results in an alcohol; use lithium aluminum hydride (LAH, or LiAlH4) for carboxylic acids and esters, and sodium borohydride (NaBH4) for aldehydes and ketones; always follow with acid workup
|
|
|
synthesis of a phenol
|
via hydrolysis of diazonium salts: aniline + HNO2, H2SO4 = benzene--N2+HSO4-, add acid = phenol
|
|
|
dehydration of an alcohol
|
proceeds in a strongly acidic solution (H2SO4), via E1... forms the most stable carbocation
|
|
|
methods of turning a hydroxyl group into a good leaving group
|
protonation (e.g., HBr, then SN1); conversion to a tosylate (p-toluenesulfonate) group (e.g., tosyl chloride, then SN2); or formation of an inorganic ester (e.g., add thionyl chloride, SOCl2, to produce a chlorosulfite and HCl -- then the chloride ion can attack via SN2, displacing SO2)
|
|
|
alcohol + PBr3
|
yields alkyl bromides, via SN2
|
|
|
alcohol + SOCl2
|
yield alkyl chlorides, via SN2
|
|
|
tosyl chloride
|
ClSO2, substituted para to toluene
|
|
|
PCC
|
pyridinium chlorochromate, C5H6NCrO3Cl, commonly used as a mild oxidant to convert primary alcohols to aldehydes without overoxidation to the acid (note: Cr(VI) is reduced to Cr(III) during the reaction); or 2* alcohols to ketones
|
|
|
KMnO4
|
a very strong oxidizing agent that will take an alcohol all the way to the carboxylic acid
|
|
|
alkali (either sodium or potassium) dichromate salt
|
Na2Cr2O7, oxidizes primary alcohols to carboxylic acids, or secondary alcohols to ketones; use with sulfuric acid
|
|
|
chromium trioxide
|
CrO3, often dissolved with dilute sulfuric acid in acetone (= Jones' reagent); it oxidizes primary alcohols to carboxylic acids and secondary alcohols to ketones
|
|
|
phenol + oxidizing reagent
|
yields quinones, e.g. 1,4-benzenediol + Na2Cr2O7, H2SO4 = p-benzoquinone (2,5-cyclohexadiene-1,4-dione)
|
|
|
oxyethane
|
cyclobutane, with oxygen substituted for one of the carbons
|
|
|
tetrahydrofuran
|
oxacyclopentane
|
|
|
ethers and bp?
|
bp similar to alkanes of comparable molecular weight because there is no hydrogen bonding
|
|
|
Williamson Ether Synthesis
|
metal alkoxide + primary alkyl halide or tosylate = ether; the alkoxide behaves as a nucleophile, displacing the halid or tosylate via an SN2 reaction. Can also be applied to phenols, and require rather mild rxn conditions due to the phenol's acidity
|
|
|
phenol + 1-bromoethane
|
ethoxybenzene (with sodium hydroxide, water)
|
|
|
cyclic ether synthesis
|
via an internal SN2 displacement (think hydroxy and halide substituents, treat with base); or oxidation of an alkene with a peroxy acid (mcpba) will produce an oxirane
|
|
|
peroxy acid
|
RCOOOH, e.g. mcpba = m-chloroperoxybenzoic acid
|
|
|
peroxide formation
|
ROOR, ether + O2
|
|
|
cleavage of an ether?
|
usually at high temperatures, acid catalyzed for straight-chains; either acid- or base-catalyzed for cyclic ethers
|
|
|
acid vs. base catalyzed cleavage of cyclic ethers
|
most substituted carbon is nucleophilically attacked in the presence of acid; whereas the least substituted carbon is attacked in the presence of base (more SN1 character because oxygen gets protonated first)
|
|
|
formaldehyde
|
methanal
|
|
|
acetaldehyde
|
ethanal
|
|
|
propanal
|
propionaldehyde
|
|
|
butanal
|
butyraldehyde
|
|
|
pentanal
|
valeraldehyde
|
|
|
formyl-
|
prefix for an aldehyde function group, e.g. m-formylbenzoic acid
|
|
|
suffix for an aldehyde
|
is -carbaldehyde, e.g. cyclopentanecarbaldehyde
|
|
|
acetone
|
2-propanone, dimethyl ketone
|
|
|
3-oxobutanoic acid
|
a 4-carbon carboxylic acid with a ketone functional group at carbon-3
|
|
|
boiling point of carbonyls
|
slightly elevated due to the dipole moment (resulting in dipole-dipole interactions); but not as high as alcohols b/c there is no hydrogen bonding
|
|
|
synthesis of a carbonyl
|
oxidation of alcohols (PCC, sodium or potassium dichromate, or Jones' reagent/chromium trioxide); ozonolysis of alkenes; Friedel-Crafts acylation
|
|
|
tautomers
|
differ only in the placement of a proton; e.g., keto and enol isomers
|
|
|
Michael additions
|
formation of an enolate carbanion with a strong base (LDA or KH) yields a nucleophile that reacts via SN2 with alpha-beta-unsaturated carbonyl compounds
|
|
|
LDA
|
lithium diisopropyl amide, a strong base
|
|
|
KH
|
potassium hydride, a strong base
|
|
|
hydration of an aldehyde or ketone
|
yields gem-diols (1,1-diols); reaction proceeds slowly but rate may be increased by the addition of a small amt of acid or base
|
|
|
acetal/ketal formation
|
aldehyde/ketone + two equivalents of alcohol, catalyzed by anhydrous acid; if one equivalent of alcohol used, then hemiacetal or hemiketals form
|
|
|
reversing acetal/ketal formation?
|
use aqueous acid
|
|
|
aldehyde/ketone + HCN
|
yields cyanohydrins; the nucleophilic cyanide anion attacks the carbonyl carbon
|
|
|
condensations with ammonia derivates (and carbonyls)
|
e.g., ammonia adds to the carbonyl carbon, loss of a water atom results in an imine (use acid to facilitate the reaction)
|
|
|
imine
|
a compound with a nitrogen atom double-bonded to a carbon atom
|
|
|
aldol condensation
|
aldehyde treated with base yields an enolate ion, which acts as a nucleophile that can react with another carbonyl group. Yields an aldol, unless under high temperatures and stronger base... then it produces an alpha, beta-unsaturated aldehyde.
|
|
|
aldol + heat
|
dehydration through E1 yields an alpha,beta-unsaturated aldehyde
|
|
|
Wittig reaction
|
converts the carbonyl to an alkene; step 1 is formation of a phosphonium salt from the SN2 rxn of an alkyl halide with the nucleophile triphenylphospine (C6H5)3P -- phosphonium salt is deprotonated at the alpha-C to phosphorus with a strong base, yielding an ylide -- ylide + carbonyl yields a betaine intermediate, which forms an oxaphosphetane intermediate which decomposes to yield an alkene and triphenylphosphine oxide.
|
|
|
ylide
|
or phosphorane, (C6H5)3P+R- -- (C6H5)3P=R
|
|
|
oxidation of aldehydes
|
KMnO4, CrO3, Ag2O, or H2O2... produces a carboxylic acid
|
|
|
reduction of an aldehyde or ketone
|
use LAH (or NaBH4 for milder conditions) to produce an alcohol
|
|
|
Wolff-Kishner
|
reduction of a carbonyl to an alkane; carbonyl + H2NNH2 = hydrazone, which releases N2 when heated and forms an alkane (use base to abstract protons)... since it is performed in basic solution, this is only useful when the product is stable under basic conditions.
|
|
|
hydrazone
|
R=NNH2, intermediate of a Wolff-Kishner reduction
|
|
|
Clemmensen Reduction
|
carbonyl heated with amalgamated zinc (Hg(Zn)) in hydrochloric acid yields an alkane
|
|
|
pKa range of the hydroxyl hydrogens of carboxylic acids
|
3 to 6
|
|
|
formic acid
|
methanoic acid
|
|
|
acetic acid
|
ethanoic acid
|
|
|
propanoic acid
|
propionic acid
|
|
|
ethanedioic acid
|
oxalic acid
|
|
|
propanedioic acid
|
malonic acid
|
|
|
butanedioic acid
|
succinic acid
|
|
|
pentanedioic acid
|
glutaric acid
|
|
|
hexanedioic acid
|
adipic acid
|
|
|
heptanedioic acid
|
pimelic acid
|
|
|
bp of carboxylic acids
|
higher than corresponding alcohols because, in addition to H-bonds, they can form dimers
|
|
|
acidity of carboxylic acids
|
is due to resonance stabilization, and can be enhanced by adding electronegative (e- withdrawing) groups or other potential resonance structures
|
|
|
e- donating groups
|
destabilize negative charges, lead to decreased acidity; e.g., -NH2 or -OCH3
|
|
|
beta-ketoacids and beta-dicarboxylic acids
|
alpha protons (between the two functional groups) are highly acidic, pKa around 10.
|
|
|
carbonation of organometallic reagents
|
example: Grignard reagent (R-MgBr) + 1)CO2 and 2) H+, H20 = R-COOH
|
|
|
Grignard reagent
|
alkyl halide + Mg, ether = R-MgX
|
|
|
hydrolysis of nitriles
|
nitrile + acid or base = carboxylic acid + ammonia (or ammonium salts, NH4+)
|
|
|
nitrile, formation
|
alkyl halide + HCN = R-CN
|
|
|
soap formation
|
long-chain carboxylic acids + NaH (or KH) = RCOO-Na+, a soap; able to solubilize nonpolar organic compounds in aqueous solutions by forming micelles
|
|
|
micelle
|
a spherical structure in which nonpolar tails surround a nonpolar organic compound, but polar heads face outward to make the compound soluble in aqueous solution; fat is solubilized in micelles with bile salts
|
|
|
nucleophilic substitution of carboxylic acids
|
RCOOH + Nu- = tetrahedral intermediate + proton = elimination of a leaving group (usually water), RCONu
|
|
|
reduction of carboxylic acids
|
use LAH to reduce to corresponding alcohols (has aldehyde intermediates, but these are also reduced), procedes via nucleophilic addition of the hydride to carbonyl group
|
|
|
carboxylic acid + alcohol
|
only proceeds under acidic conditions (oxygen of carbonyl is first protonated) -- alcohol attacks carbonyl, loss of water and reformation of C=O double bond yields an ester
|
|
|
acyl halide formation
|
RCOOH + SOCl2, H+ = RCOCl, very reactive and more susceptible to nucleophilic attack
|
|
|
decarboxylation
|
is spontaneous when 1,3 dicarboxylic acids (and other beta-keto acids) are heated; carboxyl group is lost and replaced with a hydrogen, proceeding through a 6-membered ring transition state. An enol is formed which tautomerizes to its keto form.
|
|
|
order of reactivity of carboxylic acid derivatives
|
acyl halides > anhydrides > esters > amides
|
|
|
acetyl chloride
|
ethanoyl chloride
|
|
|
benzoyl choride
|
benzyl-COCl
|
|
|
thionyl chloride
|
SOCl2 - used to prepare acid chlorides from a carboxylic acid (SO2 and HCl are side products); note: PCl3 or PCl5 can also be used to form acyl chlorides
|
|
|
formation of an acid bromide
|
carboxylic acid + PBr3
|
|
|
acyl halide + alcohol
|
yields ester via a tetrahedral intermediate
|
|
|
acyl halide + amine
|
yields an amide, RCONR2 and ammonium chloride
|
|
|
Friedel-Crafts acylation
|
benzene + acyl halide, AlCl3 (or other Lewis acid) = alkyl aryl ketone; the attacking reagent is an acylium ion formed by reaction of an acid chloride with AlCl3; mechanism = electrophilic aromatic substitution
|
|
|
reduction of acyl halides
|
to an aldehyde: acyl chloride + H2, Pd/BaSO4, quinoline = aldehyde
|
|
|
anhydrides
|
the condensation dimers of carboxylic acids, ROOCOR; name by replacing the word acid in alkanoic acid with anhydride
|
|
|
ethanoic anhydride
|
acetic anhydride
|
|
|
phthalic anhydride
|
1,2-methanoic anhydryl benzene
|
|
|
succinic anhydride
|
result of an intramolecular condensation/dehydration of succinic acid
|
|
|
o-phtalic acid (1,2-dimethanoic acid benzene) + heat
|
yields phthalic anhydride
|
|
|
synthesis of an anhydride
|
acid chloride + carboxylate salt
|
|
|
anhydride + ammonia
|
yields amide + ammonium carboxylate
|
|
|
anhydride + alcohol
|
ester + carboxylic acid
|
|
|
anydride + benzene, AlCl3
|
Friedel-Crafts acylation via electrophilic aromatic substitution mechanism yields benzyl alkanoyl acid and an alkoxy anion
|
|
|
synthesis of amides
|
by acid chloride + amine, or acid anhydride + ammonia (note: only primary or secondary amines can be used to form amides)
|
|
|
hydrolysis of amides
|
under acidic conditions, yields carboxylic acids; under basic conditions, forms carboxylates.
|
|
|
Hofmann rearrangement
|
amide + BrO- = RCNHBr + OH- = nitrene (RCON(-) Br) + H20 -- rearrangement = isocyanate (O=C=NR +Br-) hydrolyzed to the amine = H2NR + CO2 + Br-
|
|
|
reduction of amide
|
RCONH2 + LAH = RCH2NH2, yields corresponding amine
|
|
|
ethyl ethanoate
|
ethyl acetate
|
|
|
carboxylic acid + alcohol
|
condense into esters under acidic conditions
|
|
|
triacylglycerols
|
also called fats; esters of long-chain carboxylic acids (often called fatty acids) and glycerol (so three fatty acids, RCOOH, attached to glycerol at its three hydroxyl groups)
|
|
|
fatty acids
|
long-chain carboxylic acids
|
|
|
glycerol
|
1,2,3-propanetriol
|
|
|
saponification
|
process whereby fats are hydrolyzed under basic conditions to produce soaps (acidification of soaps yields triacylglycerol)
|
|
|
ammonia + ester
|
amide + alcohol
|
|
|
transesterification
|
ester + alcohol, transforms one ester into another (and yields a different alcohol)
|
|
|
ester + Grignard reagent
|
yields tertiary alcohols, since the first addition of Grignard makes a ketone that is even more susceptible to nucleophilic attach than the original ester; the ketone can only be isolated if the alkyl groups are sufficiently bulky to prevent further attack)
|
|
|
Claisen condensation
|
also called the acetoacetic ester condensation; 2 esters react under basic conditions to produce a beta-keto ester; the mechanism is analogous to to that of the aldol condensation
|
|
|
reduction of esters
|
occurs with LAH (to primary alcohols), but not with NaBH4
|
|
|
phosphate esters
|
found in living systems in the form of phospholipids (phosphoglycerides), in which glycerol is attached to two carboxylic acids and one phosphoric acid
|
