Organic Chem Midterm 2

Front 1

When do alkenes NOT have cis trans isomerism?

Back 1

When either carbon in the double bond is attached to 2 of the same groups

Front 2

What is Z geometry?

Back 2

Higher ranked groups on same side of the double bond

Front 3

What is E geometry?

Back 3

Higher ranked groups on opposite sides of double bond

Front 4

What kind of alkene is more stable?

Back 4

More substituted

Front 5

What is hyperconjugation?

Back 5

Electrons in neighbouring sigma orbitals stabilize vacant antibonding pi orbitals

Front 6

What is an antibonding orbital?

Back 6

Unfilled orbitals resembling p orbitals, carrying partial positive charge due to lack of electrons

Front 7

What does regiospecific mean?

Back 7

Reaction where only one orientation of product occurs

Front 8

What are inductive effects?

Back 8

Shifting of electrons in sigma bonds in response to electronegativity of nearby atoms, stabilizing the vacant p orbital

Front 9

___ reactions have transition states that structurally resemble a ___.

Back 9

- exergonic; reactant

- endergonic; product

Front 10

What is dehydrohalogenation?

Back 10

Loss of HX from an alkyl halide to form a multiple bond

Front 11

What reagents are used in dehydrohalogenation?

Back 11

KOH in ethyl alcohol

Front 12

What is dehydration?

Back 12

Loss of water from an alcohol to form a multiple bond

Front 13

What reagents are used in dehydration?

Back 13

H2SO4 and H2O in THF

Front 14

What is halogenation?

Back 14

Addition of X2 to form 1,2-dihalides

Front 15

What kind of stereochemistry results from halogenation?

Back 15

Anti

Front 16

What is addition of HOX?

Back 16

Creation of a halohydrin (1,2-halo alcohol)

Front 17

What are reagents used to make halohydrins?

Back 17

Br2 or Cl2 in water

Front 18

What reagents are used to create a bromohydrin?

Back 18

NBS in DMSO

Front 19

What is reduction?

Back 19

Reaction that results in gain of electron density for carbon

Front 20

What can cause reduction?

Back 20

- formation of bond between carbon and less electronegative atom

- bond breaking between carbon and a more electronegative atom

Front 21

What is hydrogenation?

Back 21

Addition of hydrogen to a multiple bond to yield a saturated product

Front 22

What stereochemistry does hydrogenation occur with?

Back 22

Syn

Front 23

What reagent is used in hydrogenation?

Back 23

H2 with Pd/C or PtO2

Front 24

What is oxidation?

Back 24

Reaction that results in a loss of electron density for carbon

Front 25

What can cause oxidation?

Back 25

- bond formation between carbon and more electronegative atom

- bond breaking between carbon and less electronegative atom

Front 26

What is an epoxide?

Back 26

Cyclic ether with an oxygen atom in a three member ring

Front 27

Alkenes oxidize to give epoxides on treatment with ____

Back 27

Peroxyacid

Front 28

Treating a base with halohydrin leads to ____

Back 28

Elimination of HX and production of an epoxide

Front 29

What happens when epoxides are treated with hydronium?

Back 29

Opening of the epoxide and creation of a 1,2-diol (glycol)

Front 30

What is the name for two step epoxidation/hydrolysis?

Back 30

Hydroxylation

Front 31

How can hydroxylation be carried out directly?

Back 31

Treatment with osmium tetroxide followed by cleaving with aqueous sodium bisulphate

Front 32

What cooxidant is used with osmium tetroxide?

Back 32

NMO

Front 33

What solvent is used with osmium tetroxide?

Back 33

Acetone and water

Front 34

What stereochemistry does the hydroxylation with osmium tetroxide produce?

Back 34

Syn

Front 35

When ozone adds to a C=C bond, what forms?

Back 35

Molozonide

Front 36

What does molozonide rearrange to form?

Back 36

Ozonide

Front 37

What is produced when ozonides are treated with a reducing agent?

Back 37

Carbonyl compounds

Front 38

What do oxidizing reagents other than ozone do?

Back 38

Double bond cleavage

Front 39

KMnO4 can produce carboxylic acids if _____

Back 39

Hydrogens are present on the double bond

Front 40

What is carbene?

Back 40

Neutral molecule containing a equivalent carbon with 6 electrons in its valence shell; R2C

Front 41

Alkene addition with a carbene yields ____

Back 41

Cyclopropane

Front 42

What does stereospecific mean?

Back 42

Only a single stereoisomer is formed as a product

Front 43

What is the Simmons-Smith reaction?

Back 43

Method for preparing nonhalogenated cyclopropanes, involving a carbenoid instead of a carbene

Front 44

What reagents are used in the Simmons Smith reaction?

Back 44

Diiodomethane with zinc copper alloy

Front 45

What are simple alkene polymers called?

Back 45

Chain growth polymers

Front 46

How do alkenes react to form polymers?

Back 46

Reaction with radical catalysts to undergo radical polymerization

Front 47

What type of radical is more stable?

Back 47

More substituted

Front 48

What happens during propagation in polymerization?

Back 48

Radical from initiation adds to alkene to generate alkene derived radical, forming polymer chain

Front 49

What happens during termination of polymerization?

Back 49

Two radical chains combine

Front 50

What is an oxymercuration intermediate?

Back 50

Reaction initiated by electrophilic addition of Hg2+ ion to alkene, corresponding to Markovnikov addition

Front 51

What is hydroboration?

Back 51

Addition of borage to an alkene to yield an organoborane intermediate, does not follow Markovnikov addition

Front 52

What reagents are involved in hydroboration?

Back 52

BH3 in THF

Front 53

What happens when hydrogen peroxide and hydroxide ions react with an organoborane intermediate?

Back 53

BH2 replaced with OH

Front 54

Treatment of a 1,2-dihaloalkane with _____ produces twofold elimination of HX

Back 54

KOH or NaOH

Front 55

What is a vinylic substituent?

Back 55

Attached to a double bond carbon

Front 56

Vinylic halides give alkynes when treated with ___

Back 56

Strong base

Front 57

What reagents are used in addition of X2 to an alkyne?

Back 57

Dihalide and dichloromethane

Front 58

What is mercury (ii) catalyzed hydration of alkynes?

Back 58

Hydration reaction with Markovnikov orientation resulting in an enol

Front 59

What kind of reaction converts terminal alkynes to methyl ketones?

Back 59

Mercury II catalyzed hydration

Front 60

What is keto enol tautomerism?

Back 60

Proton can travel from OH down a double bond to form a ketone and CH3

Front 61

What is a tautomer?

Back 61

Isomeric compound that can rapidly interconvert by movement of protons

Front 62

What is hydroboration oxidation of alkynes?

Back 62

Borane adds to alkynes giving vinylic borane in non Markovnikov orientation, and oxidation with H2O2 produces an enol

Front 63

How can you get complete reduction of an alkyne to an alkane?

Back 63

Addition of H2 with Pd/C

Front 64

How can you produce a cis alkene from an alkyne?

Back 64

Hydrogenation with Lindlar catalyst

Front 65

How can you produce a trans alkene from an alkyne?

Back 65

Hydrogenation using Na or Li in liquid ammonia

Front 66

What is oxidative cleavage?

Back 66

Cutting a multiple bond and forming carbonyl compounds

Front 67

What reagents can be used to cleave internal alkynes?

Back 67

KMnO4 or O3

Front 68

What are the products formed from cleavage of a terminal alkyne?

Back 68

A carboxylic acid and CO2

Front 69

Reaction of a strong base with a terminal alkyne results in ____

Back 69

Removal of the terminal protons and formation of an acetylide anion

Front 70

What is alkylation of acetylide anions?

Back 70

Acetyl anions react with alkyl halides, yielding new alkyne product

Front 71

How can terminal alkynes be prepared?

Back 71

Alkylation of acetylene

Front 72

Define organohalide.

Back 72

Organic compound containing at least one halogen atom

Front 73

Define alkyl halide

Back 73

Halogen atom bonded to a saturated carbon

Front 74

As you go down the periodic table, what trends are seen in C-X bonds?

Back 74

Bond lengths increase and bond strengths decrase

Front 75

What is allylic bromination?

Back 75

Alkenes react with NBS in the presence of light to produce alkyl halides

Front 76

What is the allylic position?

Back 76

Bonded to an atom bonded to a double bond carbon

Front 77

What is the most stable radical? What is the least stable?

Back 77

Most is allylic, least is vinylic

Front 78

What is delocalization?

Back 78

Allyl radicals can move on the compound and can cause a mixture of products

Front 79

What is the simplest method of deriving alkyl halides?

Back 79

Treating alcohol with HCl HBr or HI

Front 80

What do you use to convert primary/secondary alcohols into a chloro halide?

Back 80

Thionyl chloride

Front 81

What do you use to convert primary/secondary alcohols into a bromo halide?

Back 81

Phosphorus tribromide PBr3

Front 82

What do you use to convert primary/secondary alcohols into a fluoro halide?

Back 82

HF in pyridine

Front 83

What solvent do you use when preparing alkyl halides from alcohols?

Back 83

Ether or pyridine

Front 84

What is a Grignard reagent?

Back 84

RMgX

Front 85

What reagents are used to create a Grignard reagent?

Back 85

Mg in ether or THF

Front 86

What is Gilman reagent?

Back 86

LiR2Cu

Front 87

What is a Suzuki-Miyaura reaction?

Back 87

Coupling reaction for joining aromatic rings

Front 88

What does Sn2 stand for?

Back 88

Substitution nucleophilic bimolecular

Front 89

What is the reaction rate in an Sn2 reaction?

Back 89

Rate of disappearance of reactant (k[RX][OH-])

Front 90

What increases the rate of an Sn2 reaction?

Back 90

- lowering energy of transition state

- having a more unhindered substrate

Front 91

Sn2 reactions do not occur for ___ and ___ halides.

Back 91

Vinylic and aryl

Front 92

What is a nucleophile?

Back 92

Neutral or negatively charged Lewis base

Front 93

What are some trends seen in nucleophiles?

Back 93

- negative charge generally more reactive than neutral

- increases with downward progression in periodic table

- roughly parallels basicity

Front 94

What are the best leaving groups?

Back 94

Groups that can most stably hold a negative charge

Front 95

___ bases are good leaving groups and ___ bases are poor leaving groups.

Back 95

Weak, strong

Front 96

What are characteristics of a good solvent for Sn2 reactions?

Back 96

Polar and aprotic

Front 97

What happens to an Sn2 reaction if a solvent is protic?

Back 97

Hydrogen bonding between the solvent and electrophile resulting in reduced reactivity