Orgo Test 3 Reactions

Front 1

What type of halide & base are used in an Sn1 Reaction?

Back 1

Tertiary Alkyl Halide
Weak Base

Front 2

What is the basic mechanism of an Sn1 Reaction?

Back 2

Halide leaving group forms carbocation which is attacked by the base

Front 3

What is the stereochemical result if there is a stereocenter in an Sn1 Reaction?

Back 3

Both frontside and backside attacks occur producing a racemic mixture

Front 4

What is the best soldvent for an Sn1 Reaction? Examples?

Back 4

Polar Protic Donor
Ex. Methanol, water, ethanol

Front 5

What type of halide & base is used in an E1 Reaction?

Back 5

A tertiary alkyl halide wiht a stron, bulky base

Front 6

What is the basic mechanism of an E1 Reaction?

Back 6

Leaving group leaves substrate to form carbocation, base attacks one B-hydrogen and double bond is formed between a & B carbons

Front 7

What is the regioselectivity of an E1 Reaction?

Back 7

The product with the most branching at the double bond is dominant (Zaitsev's Rule)

Front 8

What is the best solvent for an E1 Reaction? Examples?

Back 8

Polar Protic Donor
Ex. Methanol, water, ethanol

Front 9

What is the halide & base type for an Sn2 Reaction?

Back 9

Primary alkyl halide with a weak base

Front 10

What is the basic mechanism for an Sn2 reaction?

Back 10

Electron pair of base attacks a-carbon and halide group leaves allowing the base to take place of halide on molecule

Front 11

What is the sterochemical result of an Sn2 reaction if there is a stereocenter present?

Back 11

Only backside attack can occur causing an inversion of configuration

Front 12

What is the best solvent for an Sn2 Reaction? Examples?

Back 12

Polar Aprotic Donor
Ex. Acetone, DMSO, DMF, MeCN

Front 13

What is the halide and base type for an E2 Reaction?

Back 13

Primary alkyl halide with a strong, bulky base

Front 14

What is the basic mechanism for an E2 Reaction?

Back 14

Electron pairs on base attack B-hydrogen allowing double bond to form between a & B carbons causing halide to leave from the a-carbon

Front 15

What is the stereochemical result if there is a stereocenter in an E2 Reaction?

Back 15

Anti-elimination always occurs in order to minimize steric strain

Front 16

What is the regioselectivity of a E2 Reaction?

Back 16

Product with most branching at double bond is the most major product formed

Front 17

What is the best solvent for an E2 Reaction? Examples?

Back 17

Polar Aprotic Donor
Ex. Acetone, DMSO, DMF, MeCN

Front 18

What is the alcohol & reactant type for the dehydration of alcohols?

Back 18

A secondary or tertiary alcohol can react with an acid

Front 19

What is the basic mechanism for the dehydration of alcohols?

Back 19

E1 Mechanism: -OH group accepts a proton from acid, carbon-oxygen bond breaks forming carbocation, water attacks B-hydrogen to form alkene

Front 20

What alcohol type proceed by what reactions to convert alcohols to alkyl halides via hydrogen halides?

Back 20

Primary alcohols proceed via Sn2 Reactions
Secondary and tertiary alcohols proceed via Sn1 Reactions

Front 21

What is the basic mechanism for a primary alcohol reacting with a hydrogen halide?

Back 21

Sn2 Mechanism: hydrogen halide protonates alcohol, halide ion attacks a-carbon causing water leaving group to leave and alkyl halide to form

Front 22

What is the basic mechanism for a secondary or tertiary alcohol reacting with an hydrogen halide?

Back 22

Sn1 Mechanism: hydrogen halide protonates alcohol, water leaves as leaving group forming carbocation, halide attacks carbocation forming alkyl halide

Front 23

Through what mechanisms to primary alcohols convert most easily to alkyl halides?

Back 23

HBr/PBr3
HI
SOCl2
Sulfonate Esters: OM/OT/Cl, I, Br

Front 24

Through what mechanisms do secondary alcohols convert most easily to alkyl halides?

Back 24

PBr3
SOCl2
Sulfonate Esters: OM/OT/Cl, I, Br

Front 25

Through what mechanisms do tertiary alcohols convert most easily to alkyl halides?

Back 25

HBr
HCl

Front 26

What alcohol and reactants are used for the conversion of alcohols to alkyl halides via sulfonate esters?

Back 26

Primary and Secondary alcohols with tosylate (OT), mesylate (OM) or triflate (OTfs) and the solvent pyridine

Front 27

What is the basic mechanism for formation of alkyl halides by sulfonate esters?

Back 27

Hydrogen leaves and ester takes place, ester becomes good leaving group and when a-carbon is attacked by halide it is ejected from molecule

Front 28

What is the alcohol type and reactants for alkyl halide formation via thionyl chloride?

Back 28

Primary and secondary alcohols with SOCl2 and pyridine

Front 29

What is the basic mechanism for alkyl halide formation via thionyl chloride?

Back 29

Thionyl cholride reacts with alcohol to form chlorosulfiteester, chloride ion attacks a-carbon forcing leaving group to leave and alkyl chloride forms

Front 30

What is the alcohol type and reactants for alkyl halide formation via phosophorus tribromide?

Back 30

Primary and secondary alcohols with PBr3 and pyridine

Front 31

What is the basic mechanism for alkyl halide formation via phosophorus tribromide?

Back 31

-OH group attacks phosphorus and ejects on bromide and forms bond with phosphorus, bromide attacks a-carbon forcing leaving group out and forming alkyl bromide

Front 32

What are the two possible oxidations for a primary alcohol? What is the oxidizing agent & resulting molecule?

Back 32

Primary Alcohol + weak, anhydrous oxidizing agent forms an aldehyde
Primary alcohol + strong, aqueous oxidizing agent forms a carboxylic acid

Front 33

What are anhydrous oxidizing agents?

Back 33

PDC/CH2Cl
PCC/CH2Cl
CrO3/pyridine

Front 34

What are aqueous oxidizing agents?

Back 34

KMnO4/OH-
NaCr2O7/H2SO4/H2O
K2Cr2O7/H2SO4/H2O
H2CrO4/H2SO4/H2O

Front 35

What is the result of oxidation of a secondary alcohol? What oxidizing agents are used?

Back 35

Ketone is formed through any oxidizing agent aqueous or anhydrous

Front 36

What are the three ways thiols are oxidized into disulfides?

Back 36

I2/base
Br2/CCl4
spontaneously with O2

Front 37

What are the two ways thiols or disulfides are further oxidized into sulfonic acids?

Back 37

KMnO4
conc. HNO3

Front 38

What is a grignard reagent?

Back 38

R-MgBr or R-MgCl or R-MgI

Front 39

What is the basic mechansim of converting an alkyl halide to an alkane or alkene using grignards?

Back 39

Alkyl halide reacts with magnesium to form grignard, grignard reacts with water or alcohol causing MgCl to bond with -OH or -OR leaving only alkane/alkene

Front 40

What solvent is used for grignard reagent reactions?

Back 40

ether solvents (THF, diethyl ether)

Front 41

What is an organolithium reagent?

Back 41

R-Li

Front 42

What is the basic mechanism for converting alkyl halides to alkanes or alkenes using organolithium reagnets?

Back 42

Alkyl halide reacts with Li to form organolithium reagent which reacts with water or alcohol forming LiOH or LiOR and leaving only alkane or alkene

Front 43

What solvent is used in organolithium reagent reactions?

Back 43

Hydrocarbons (hexane)

Front 44

What are the reactants of Williamson Ether Synthesis?

Back 44

An alkoxide reacts with a alkyl halide to form an ether

Front 45

What is the basic mechanism of a Williamson Ether Synthesis?

Back 45

Alkoxide attacks the carbon of alkyl halide and halide leaves forming ester (ROR)

Front 46

What type of alkyl halide is needed for a Williamson Ether Synthesis?

Back 46

methyl or primary

Front 47

What are the reactants need for alkoxymercuration-reduction reaction?

Back 47

Alkene reacts with alcohol solvent and Hg(OAc)2 then reacting with NaBH4/OH- to make an ether

Front 48

What is the basic mechanism of alkoymercuration-reduction?

Back 48

Electrons of double bond attack Hg to form Hg ring which is broken by alcohol attacking more subbed carbon.
Deprotonation of alcohol happens by another alcohol and Hg leave by attack of hydrogen anion

Front 49

What reactants are needed to form an ether by condensation?

Back 49

Two alcohols in a strong acid with heat

Front 50

How is an epoxide made in an acid?

Back 50

An alkene reacts with mCPBA in an concerted mechanism

Front 51

What is the stereochemsitry of expoxidation of alkenes in an acid?

Back 51

Retention of configuration, syn addition

Front 52

How is an epoxide made from a halohydrin?

Back 52

Halohydrin is deprotonated by base and alkoxide attacks internally at halide carbon making it leave and forming epoixde

Front 53

What is the stereochemistry of a epoxide formation in a base?

Back 53

Diaxial conformation is required for O- to do backside attack

Front 54

How is a epoxide ring opened in a base?

Back 54

Alkoxide attacks carbon breaking ring and which then reacts with lewis acid to make -OH & -OR groups

Front 55

What is sterochemistry of epoxide ring opening in acidic conditions?

Back 55

Sn2 so inversion of configuration

Front 56

What is the regioselectivity of epoxide ring opening in basic conditions?

Back 56

Less subbed carbon is attacked to minimize sterics

Front 57

How is an epoxide ring opened in acidic conditions?

Back 57

Epoxide is protonated then conjugate base attacks carbon to open ring and form halohydrin

Front 58

What is sterochemistry of epoxide ring opening in acidic conditions?

Back 58

Inversion of configuration

Front 59

What is the regioselectivity of epoxide ring opening in acidic conditions?

Back 59

More subbed carbon is attacked to minimize electronics

Front 60

How is a grignard used to open an epoxide ring?

Back 60

Grignard reacts attacks ethylene oxide to open ring and form primary alcohol by protonation of O-

Front 61

What are reagents of epoxide/grignard reaction?

Back 61

Diethyl ether, heat, H3O+

Front 62

How does Acetylenic Anion react with alkyl halide?

Back 62

Anion attacks carbon which forces halide to leave thus lengthening carbon chain and adding triple bond