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Flashcards in Organic Reactions Deck (46):
1

Lewis acid

Electron acceptor, vacant orbitals or positively polarized atoms

2

Lewis base

Electron donors, lone pair and often are anions

3

Bronsted-lowry acid

Proton donors

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Bronsted-lowry base

Proton acceptors

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Amphoteric molecules

Can be acidic or basic. Water common example

6

Acid dissoc constant, Ka

Measure of acidity. Equilibrium constant corresponding to dissociation of an acid into a proton and conj base

7

pKa

Negative log of Ka
lower pka is a stronger acid
Decreases down periodic table and increases with electronegativity

8

Nucleophile

Nucleus-loving
Contain lone pairs or pi bonds. Increased electron density and often carry negative charge
Similar to basicity but is a kinetic property
Charge, electronegativity, sterics, solvent all affect
Amino groups common nucleophiles

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Electrophile

electron loving contain positive charge or are positively polarized
Alcohols, aldehydes, ketones, carboxylic, derivatives

10

LG quality

Best ones stabilize additional charge through resonance or induction
Weak bases
Alkanes, hydrogen ions are almost never leaving groups because they form unreactive anions

11

SN1 reactions

Two steps
1. LG leaves, forming carbocation
2. Nucleophile attacks planar carbocation from either side (racemic mixture)
Prefer more substituted carbons
Rate is dependent only on the concentration of the substrate

12

SN2

One concerted step
Nucleophile attacks at same time that leaving group leaves
Backside attack only, inverts stereochemistry
Prefer less substituted carbons because the alkyl groups create steric hindrance and inhibit nucleophile from accessing electrophilic substrate carbon
Depends on concentrations of both substrate and nucleophile

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Oxidation state

Charge it would have if all bonds were ionic

14

Oxidizing agents

Get reduced. accept electrons. High affinity for electrons or an unusually high oxidation state. Often contain a metal and large amount of O

15

PCC

Oxidizes primary alcohols to aldehydes

16

CrO3

Oxidizes primary alcohols all the way to carboxylic acids

17

Reducing agents

get oxidized. Donate electrons and are oxidized in the process. Low electronegativity and ionization energy. Often contain metal and large number of hydrides

18

LiAlH4

Reduces aldehydes, ketones, carboxylic acids to alcohols
amides reduced to amines
esters reduced to pair of alcohols

19

Phenol

Benzene ring with hydroxyl groups
More acidic than other alcohols because aromatic ring can delocalize charge

20

Aldol condensation

Reaction in which an aldehyde or ketone acts as both electrophile and nucleophile, resulting in formation of a C-C bond in a new molecule- aldol

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Gabriel (malonic-ester) synthesis

Method of synthesizing amino acids that uses potassium phthalimide and diethyl bromomalonate followed by an alkyl halide; two substitution rxns are followed by hydrolysis and decarboxylation

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Jones oxidation

Primary alcohols are oxidized to carboxylic acids and secondary alcohols oxidized to ketons, needs CrO3 dissolved with dilute sulfuric acid in acetone

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Lactam

Cyclic amide; named according to the Greek letter of the carbon closing it

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Lactone

Cyclic ester; named according to greek letter of carbon closing ring and for straight-chain form of compound

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Michael addition

Rxn in which a carbanion attacks an alpha beta unsaturated carbonyl

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Strecker synthesis

Method of synthesizing amino acids that uses condensation between an aldehyde and hydrogen cyanide, followed by hydrolysis

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In oxidation, a C loses a bond to ___ and gains a bond to ___

H, O

28

NAD+ --> NADH is a ___ half-reaction

Reduction

29

You can tell H's will be rich in e- and therefore make the molecule a good reducing agent but seeing

that they are at the end of a molecule, cations come first and anions come last. i.e. sodium borohydride tells us that the Hs carry negative charge

30

Converting pyruvate to lactate involves the ___ of the ____ C

Reduction, second

31

FAD is ____ to form FADH2

Reduced

32

FAs are built ____ Cs at a time

2

33

Aliphatic acid

Contains no C-C pi bonds

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Good LG should have a (high/low) pKb value

High (weak base)

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Function of SOCl2

Converts an acid functionality into an acid chloride, making it a good LG

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Grignard reagent + carbonyl yields

Alcohol

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Ester reacted with excess Grignard yields

Achiral tertiary alcohol (adds same R-group twice)

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A Grignard reagent is a ____ and as such needs a _____ solvent

Strong base, aprotic (like ether)

39

An aldehyde treated with excess alcohol in the presence of an acid catalyst will form ___

an acetal, losing a molecule of water as well

40

Aldehyde treated with excess alcohol in basic environment will yield

Hemiacetal

41

Wittig reaction

Coupling reaction that forms an alkene. Requires reactant with O3P group bonded to a carbon. (phenyl group) Couples a phosphoylid with a ketone (or aldehyde) to form the alkene.

42

Aldol condensation

One ketone (or aldehyde) reacts with itself, dimerization

43

pKa of a ketone is

17-10, requires SB for deprotonation

44

Only ___ and ___ can undergo aldol condensations

Ketones and aldehydes

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Baeyer-Villiger oxidation

Ketone is converted into an ester (or an aldehyde into a carboxylic acid) by an insertion reaction with a peroxyacid

46

Intramolecular Claisen condensation results in a

Cyclic beta ketoester